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Development of a fluid treatment strategy to enable combined raw material and freshwater recovery from geothermal fluids
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This study provides background information on the potential of future lithium production from geothermal fluids in Germany. Growing demand and the dependence on poorly diversified overseas sources point toward a high strategic importance of domestic resources. Potentially lower CO2 emissions and reduced areal use during lithium production are additional aspects that need to be considered.
Based on the technology comparison for direct lithium extraction from geothermal fluids and the current state of geothermal energy production in Germany and the French part of the Upper Rhine Graben, different scenarios for the extractable amount of lithium carbonate were calculated. In the most optimistic scenario, taking into account all currently active wells, a maximum production of 7200 t/a of lithium carbonate equivalent is expected. This could cover 5 - 19 % of the annual demand of the planned German battery cell production.
Key parameters for the process design are the usable volume fraction of the geothermal fluid and the extraction efficiency. The uncertainties in resource assessment regarding the size and sustainability of its management are still considerable. To exploit the great potential of this technology, these key issues need to be addressed.
This study assesses the status of currently available extraction technologies for lithium recovery from geothermal waters based on recent scientific studies and identifies potential technical challenges. Available technologies such as liquid-liquid extraction, selective extraction by inorganic sorbents, electrochemical methods, and membrane technologies are evaluated in terms of their applicability and integrability in geothermal energy production. Current research projects have validated various extraction methods at laboratory and, in some cases, prototype scale. Scaling up to an industrial process does not exist yet. Accordingly, information regarding continuous operation as well as site-specific challenges (water chemistry, volume flow, flow rates, etc.) and actual economic viability is lacking. The amount of recoverable lithium depends primarily on the concentration of lithium dissolved in the water, the extraction efficiency and rate, and the amount of extractant used. The interaction of these factors determines the process technology and the size of the extraction infrastructure. Depending on the chosen Li extraction method, physicochemical properties of the water (pH, Eh, T, p, etc.) are altered during extraction, which can increase scaling and corrosion potential.
The current state of the art shows an early to medium technology readiness level while reaching lithium extraction efficiencies of 50 – 90 % in laboratory experiments. Under the disproportionately higher challenges in the ongoing operation of a geothermal power plant, extraction efficiencies at the bottom of this range are considered realistic.
Lithium is the principal component of high-energy-density batteries and is a critical material necessary for the economy and security of the United States. Brines from geothermal power production have been identified as a potential domestic source of lithium; however, lithium-rich geothermal brines are characterized by complex chemistry, high salinity, and high temperatures, which pose unique challenges for economic lithium extraction. The purpose of this paper is to examine and analyze direct lithium extraction technology in the context of developing sustainable lithium production from geothermal brines. In this paper, we are focused on the challenges of applying direct lithium extraction technology to geothermal brines; however, applications to other brines (such as coproduced brines from oil wells) are considered. The most technologically advanced approach for direct lithium extraction from geothermal brines is adsorption of lithium using inorganic sorbents. Other separation processes include extraction using solvents, sorption on organic resin and polymer materials, chemical precipitation, and membrane-dependent processes. The Salton Sea geothermal field in California has been identified as the most significant lithium brine resource in the US and past and present efforts to extract lithium and other minerals from Salton Sea brines were evaluated. Extraction of lithium with inorganic molecular sieve ion-exchange sorbents appears to offer the most immediate pathway for the development of economic lithium extraction and recovery from Salton Sea brines. Other promising technologies are still in early development, but may one day offer a second generation of methods for direct, selective lithium extraction. Initial studies have demonstrated that lithium extraction and recovery from geothermal brines are technically feasible, but challenges still remain in developing an economically and environmentally sustainable process at scale.
The BrineMine Project is a German-Chilean multidisciplinary research project realized by research and industry partners. The focus is developing strategies for raw material and water extraction from geothermal springs (Brine Mining) in Chile. The topics can be separated into a geological/geochemical part and a mechanical engineering part, which are processed in close cooperation by the project consortium. In the first part, the economic potential of the dissolved raw materials in thermal spring waters in Chile is assessed by analyzing existing geochemical data of different sites. This is complemented by hydrogeochemical and geophysical exploration campaigns. The second part focuses on the development, construction and implementation of a prototype for pre-treatment and concentration of geothermal brines. With the comprehensive expertise of the team, a treatment strategy was developed and tested in a geothermal power plant, enabling controlled silica precipitation in order to overcome this limiting factor for geothermal energy production and associated raw material extraction.
In this study, successful milestones of the BrineMine project are presented. The economic potential of elements in Chilean thermal waters is demonstrated. Additionally, the global potential of Brine Mining is outlined. The development of the silica treatment strategy is further described, as well as a possible integration of a prototype into an operating geothermal power plant. Finally, the construction and implementation of a large-scale first-generation prototype are presented with promising field results.
As the demand for electric vehicles (EVs) increases, demand for lithium (Li) is expected to grow over the coming decade. To satisfy the demand for rechargeable batteries, it is imperative to devise solutions for sufficient Li production. Even though commercial Li currently comes from conventional saline salar brine and spodumene ore extractions, efforts to retrieve Li from geothermal brines are increasing in popularity. In this paper, we evaluate the United States’ potential to supply Li from geothermal brines using Systems Dynamics modeling. The main goals are to assess (1) the viability of US Li supply from geothermal brines and (2) the potential supply chain impact of extracting Li from this source. Results show that Li supply from geothermal brines could (1) reach around 4% to 8% of total US Li supply and (2) be economically viable.
Lithium is becoming increasingly important due to its essential role in lithium-ion batteries. Over 70% of the global lithium resources are found in salt lake brines, but lithium is always accompanied by magnesium. It is a challenge to efficiently separate lithium from magnesium in brines. The state-of-the-art processes for lithium/magnesium separation either consume large quantities of chemicals and generate large amounts of waste, or are energy-intensive. In this study, we develop a sustainable solvent extraction process based on binary extractants to efficiently separate lithium and magnesium. A binary extractant comprised of Aliquat® 336 and Versatic Acid® 10, [A336][V10], was prepared and investigated for removal of magnesium from both a (synthetic) concentrated brine (106 g L-1 Mg and 10 g L-1 Li) and an (synthetic) original brine (15 g L-1 Mg, 80 g L-1 Na and 0.2 g L-1 Li). Through batch counter-current experiments and mixer-settler experiments, it was found that [A336][V10] is able to quantitatively remove magnesium from the original brine in three continuous counter-current extraction stages with as little as about 10% co-extraction of lithium. The loaded organic phase can be stripped and regenerated by water. The whole process (extraction and stripping) does not consume any acid or base, but makes use of the differences in the chloride concentration during extraction and stripping. This process is an environmentally friendly alternative to the state-of-the-art processes and represents a step forward in the sustainable production of Li2CO3 from brines.
Membrane distillation (MD) is an up and coming technology for concentration and separation on the verge of reaching commercialization. One of the remaining boundaries is the lack of available full-scale MD modules and systems suitable to meet the requirements of potential industrial applications. In this work a new type of feed gap air gap MD (FGAGMD) plate and frame module is introduced, designed and characterized with tap water and NaCl–H2O solution. The main feature of the new channel configuration is the separation of the heating and cooling channel from the feed channel, enabling a very high recovery ratio in a single pass. Key performance indicators (KPIs) such as flux, gained output ratio (GOR), recovery ratio and thermal efficiency are used to analyze the performance of the novel module concept within this work. A recovery rate of 93% was reached with tap water and between 32–53% with salt solutions ranging between 117 and 214 g NaCl/kg solution with this particular prototype module. Other than recovery ratio, the KPIs of the FGAGMD are similar to those of an air gap membrane distillation (AGMD) channel configuration. From the experimental results, furthermore, a new MD KPI was defined as the ratio of heating and cooling flow to feed flow. This RF ratio can be used for optimization of the module design and efficiency.
Abstract Hydrogeochemical modelling has become an important tool for the exploration and optimisation of deep hydrogeothermal energy resources. However, well-established software and model concepts are often run outside of its temperature, pressure, and salinity ranges. The core of the model codes are thermodynamic databases which contain a more or less complete subset of mineral phases, dissolved species, and gases occurring in geothermal systems. Although very carefully compiled, they should not be taken for granted at extreme conditions but checked prior to application. This study compares the performance of four commonly used geochemical databases, phreeqc.dat, llnl.dat, pitzer.dat, and slop16.dat. The parameter files phreeqc.dat, pitzer.dat, and llnl.dat are distributed with PHREEQC and implement extended Debye–Hückel and Pitzer equations. Thermodynamic data in slop16.dat represent an implementation of the revised Helgeson–Kirkham–Flowers formalism and were converted to be used with the Gibbs Energy Minimizer ChemApp for this work. Test calculations focussed on the solubility for some of the most common scale-forming mineral phases (barite, celestite, calcite, siderite, and dolomite). The databases provided with PHREEQC performed comparatively well, as long as the range of validity was respected for which the corresponding database was developed. While it is obvious to use pitzer.dat at high salinities instead of phreeqc.dat, the range of validity for high temperature is usually not given in the database and has to be checked manually. The results also revealed outdated equilibrium constants for celestite in slop16.dat and llnl.dat and the lack of adequate temperature functions for the solubility constants of siderite and dolomite in all databases. For those two minerals, new thermodynamic data are available. There is, however, a lack of experimental thermodynamic data for scale-forming minerals in low-enthalpy geothermal settings, which has to be addressed for successful modelling.
Lithium is a key component in green energy storage technologies and is rapidly becoming a metal of crucial importance to the European Union. The different industrial uses of lithium are discussed in this review along with a compilation of the locations of the main geological sources of lithium. An emphasis is placed on lithium’s use in lithium ion batteries and their use in the electric vehicle industry. The electric vehicle market is driving new demand for lithium resources. The expected scale-up in this sector will put pressure on current lithium supplies. The European Union has a burgeoning demand for lithium and is the second largest consumer of lithium resources. Currently, only 1–2% of worldwide lithium is produced in the European Union (Portugal). There are several lithium mineralisations scattered across Europe, the majority of which are currently undergoing mining feasibility studies. The increasing cost of lithium is driving a new global mining boom and should see many of Europe’s mineralisation’s becoming economic. The information given in this paper is a source of contextual information that can be used to support the European Union’s drive towards a low carbon economy and to develop the field of research.
Since the 1980′s, more than 15 geothermal wells have been drilled in the Upper Rhine Graben (URG), representing more than 60 km of drill length. Although some early concepts were related to purely matrix-porosity reservoirs or Hot Dry Rock systems, most projects in the URG are currently exploiting the geothermal resources that are trapped in fracture networks at the base of the sedimentary cover and in the granitic basement. Lessons-learnt from the European EGS reference site at Soultz-sous-Forêts reveal highest natural permeability in the uppermost altered crystalline basement. Here, we present a compilation of related information to examine a more general validity of this hypothesis for the central URG. In this respect, 15 geothermal wells were analyzed concerning their lithologies, temperature distribution with depth, and their hydraulic yields. Among others, permeable fractures in Triassic sediments were observed among others during drilling operations at Soultz-sous-Forêts, Rittershoffen, Cronenbourg (France), Landau, Insheim, Bruchsal and Brühl (Germany). The geothermal wells at Soultz-sous-Forêts, Rittershoffen (France), Landau and Insheim (Germany) also intersect well-connected fracture networks in the uppermost altered granitic basement. Permeable fractures are intersected to a depth of 5 km at Soultz-sous-Forêts (France) and Basel (Switzerland). The compilation of geologic, hydraulic and thermal data of 15 geothermal wells shows permeability variation among the lithologies with the maximum observed at the top of the hydrothermally altered granite. This higher permeability is likely due to the intense fracture density in the fault core of the fracture zone and the large porous and altered damage zone which allow connection with the reservoir.
Water composition during cement hydration can be changed due to migration of ions from the cement matrix to the solution. The storage of various materials together can lead to transfer of various ions and distortion of results. This article is aimed on the influence of storage environment on the Portland cement hydration and hydrated samples composition. Test specimens were prepared and stored in different environments. Storage environments were ultrapure water and solutions having alkaline and acidic pH value. The mechanical properties were measured after 1, 7 and 28 days. Composition of samples stored in different environment was tested by X-ray diffraction and DTA analysis.
We demonstrated an efficient recovery of lithium ions (Li+) from seawater using a continuous flow column packed with an adsorbent, chitosan-lithium manganese oxide (LMO). The effects of Li+ concentration, contact time and recyclability were investigated. The adsorbent showed good removal efficiency of Li+ from seawater. The maximum adsorption capacity was calculated to be 54.65 mg/g. The adsorption process fit-well with the Freundlich isotherm with a correlation coefficient of 0.9924. Kinetics studies showed that the adsorption process was consistent with the pseudo second-order model. The recyclability was tested after extraction of Li+ from the adsorbent using sulfuric acid. The adsorption capacity decreased slightly after recycling the adsorbent for three times. This may be due to the dissolution of Mn2+ and deformation of the chitosan structure. A study of the selectivity of Li+ in seawater showed that the selectivity increased in the order of Li+ > Mg2+ > Na+.
This study focuses on calcium sulfate (gypsum) and calcium carbonate (CaCO3) simple and mixed precipitations. These forms of scaling are still an issue in several industrial applications such as cooling towers and water desalination, either by thermal-based or membrane-based processes.
CaCO3 precipitation has been studied by the degassing method while the gypsum simple and mixed precipitations have been studied by the double decomposition method, and by following 4 parameters simultaneously, namely: pH and total alkalinity serve to detect the CaCO3 precipitation, calcium ion concentration allows following the gypsum germination, and the quartz crystal microbalance (QCM) response gives information about the salts seeding, especially gypsum. A kinetic study of CaCO3 and
CaSO4・2H2O mixed precipitation resulted in a different form to that of the simple precipitation. Indeed, even though the pH remains the key parameter to detect CaCO3 precipitation either under simple or mixed precipitation forms, as the QCM response was found not to be a good parameter to detect the CaCO3 germination in a mixed system, especially when it precipitates after calcium
sulfate, the QCM response remains a specific parameter to gypsum crystals because even after the appearance of the first CaCO3 crystals, gypsum germination continues with faster kinetics. Gypsum germination time in co-precipitation is higher than that corresponding to the simple precipitation (CaSO4-H2O system) because of the competition between the different coprecipitating ions.
Highly saline geothermal fluids typically contain a complex mixture of metals that are responsible for precipitation of various minerals during the operation of geothermal plants. This has resulted in significant clogging of the production well at the geothermal site Groß Schönebeck (Germany).
Databases distributed with PHREEQC may give widely different results for concentrated solutions. Only the database that uses Pitzer’s interaction coefficients provides both correct solubilities and mean activity coefficients. The applicability of this database for predicting scaling by mineral precipitation is extended by fitting interaction coefficients for the Na-K-Mg-Ca-Ba-Cl-CO2-HCO3-SO4-H4SiO4 system from isopiestic and solubility data at high temperatures. The pressure dependence of equilibrium constants is calculated from the reaction volume, in which the apparent molar volume of the solutes is derived from density measurements. The apparent volumes are a function of temperature, pressure, and ionic strength, and incorporate complicated changes of the partial molar volumes of the water molecules.Fugacity coefficients for CO2 can be obtained reliably with the Peng-Robinson equation of state for gases. The CO2 ion interaction parameters given by Harvie et al. (1984) for 25 °C are also valid for calculating the CO2 solubility at high temperatures, pressures and salinities.PHREEQC input files are available for download, comparing experimental and calculated solubilities of (Na, K, Mg, Ca, Ba) minerals of chlorides, sulfates and carbonates, and of amorphous silica and CO2 in concentrated solutions.
Thermodynamic data are an essential input for relevance of geochemical modeling and more particularly to assess the behavior of radionuclides and other pollutants in the performance assessment of a radioactive waste repository. ThermoChimie (http://www.thermochimie-tdb.com/), the thermodynamic database developed by Andra, meets the requirements of completeness, accuracy and consistency for numerous radionuclides and chemotoxic elements and various major components of a geological repository: solid phases constitutive of the host-rock, bentonites, concretes, and corresponding secondary minerals with respect to their long term evolution. ThermoChimie developments are also dedicated to evaluating specific conditions of the near field of radioactive waste, in particular regarding temperature increase and release of organic ligands or soluble salts. ThermoChimie database is extracted into compatible formats with different geochemical codes, allowing an overall consistency between different models using it in support.
The development of Thermoddem, a thermodynamic database devoted to geochemical modelling for environmental studies in general and, more specifically, to chemical systems involving waste materials, is discussed here. Concerns are also focused on taking into account some specific needs for modellers by proposing different output formats and some important information concerning the solid phases, the transformation path, paragenesis and insights into crystallographic details. This additional information aims to avoid considering phases that may not be “active” under current environmental conditions. The database is especially devoted to environmental applications, ranging from waste material management to pollutant behaviour, including the context of deep underground disposal. Selection rules and conventions are illustrated through the example of the Fe-water system, while a second example details the relationships between low and high ionic strength media, from the point of view of thermodynamic databases. Technical aspects concerning the development of a management information system for Thermoddem and its availability on the web (http://thermoddem.brgm.fr) are also provided.
Geothermal power plants produce large amounts of high-temperature fluids from variable depths. These fluids can be enriched in lithium to up to 240 mg/L, rendering them an exploitable resource, not yet processed at industrial scale. The pressure on Li demand is expected to increase in the future, making the technical degradability of new Li resources indispensable. We examine Li-extraction methods from aqueous solutions systematically, dealing with evaporation, direct precipitation, membrane-related processes, solvent extraction, sorption, and ion exchange. Sorption and ion-exchange techniques are regarded to be the most promising methods with a high potential for the feasible lithium extraction. Therefore, Li sorption on different inorganic sorbents, in particular for the implementation into operating geothermal power plants, is evaluated. Inorganic sorbents, such as lithium–manganese oxide, titanium oxide, aluminum hydroxide, iron phosphate, clay minerals, and zeolite group minerals besides other sorbents, e.g. zirconium phosphate, tin antimonate, antimony oxide, tantalum oxide, and niobium oxide, are regarded. Promising inorganic sorbents for an environmentally friendly, efficient, and selective Li extraction are lithium–manganese oxide, iron phosphate, or zeolite. To evaluate the effectiveness of these sorbents to large-scale industrial Li2CO3 (or LiOH) production, we highlight their potential advantages and disadvantages in the application under geothermal operating conditions.
Lithium (Li) is a strategic metal - especially for batteries in electric vehicles - for which worldwide demand is constantly increasing. Presently, several investigations are examining if a part of lithium could be extracted from deep European geothermal fluids. Among the data from geothermal and hydrocarbon wells found in the literature review carried out by BRGM and EIFER, only six areas stand out with deep fluids containing high Li concentrations from 125 to 480 mg/l in Italy, Germany, France and the United-Kingdom. Except the UK fluid, which has a relatively low salinity (TDS = 19 g/l) and reservoir temperature (around 52 °C), these deep Li-rich fluids are Na-Cl brines (TDS ≥ 56 g/l) with high concentrations of Na (> 18 g/l) and Cl (> 25 g/l) and high temperatures (≥ 120 °C and up to 380 °C in Italy). If high TDS and temperature values seem to be key factors for triggering high Li concentrations in such fluids, these two factors alone cannot be sufficient. Indeed, our study confirms that Li concentrations not only depend on temperature and fluid salinity, but also on the type of reservoir rock and its mineralogical constituents, as demonstrated by the good results obtained using two different Na-Li thermometric relationships existing in the literature. One fits well with the brines from low to high temperature (120–250 °C) reservoirs in deep tectonic sedimentary basins over a crystalline basement (France, Germany) and the other with the fluids from ultra-high temperature (≥ 300 °C) reservoirs in volcano-sedimentary environment (Italy). If the high chloride concentrations values in these brines mainly depend on the fluid origin (evaporated seawater or freshwater, halite dissolution, primary neutralization fluids or parent-geothermal fluids in high-temperature and -pressure volcanic environments, water mixing, etc.), the other aqueous major species are mostly controlled by hydrothermal water-rock interaction processes. At these temperatures (≥ 120 °C), the fluid-rock interaction processes are generally dominated by plagioclase and K-feldspar dissolution, followed by albitization of these minerals, dissolution of white micas and biotite, precipitation of illite, and chloritization. According to the two Na-Li thermometric relationships, existing mineralogical and isotopic data, this study suggests that the main sources of Li are white micas and biotite dissolution. Among the European areas, it shows that the Upper Rhine Graben (URG) along the French/German border is probably the most promising zone. For the URG geothermal brines, the main source and control of lithium, at about 225 °C, at reservoir depth, is probably the up to 450-m-thick micaceous continental sandstone of Triassic Buntsandstein. A minor contribution from the granite basement can also not be excluded. Though the Li concentration values of these brines (≥ 150 mg/l) seem to be favourable for geothermal Li exploitation, it is essential to make an as accurate as possible estimate of the Li resource of these brines, design the Li extraction process, and examine the economic conditions of its exploitation.
Raw material extraction from geothermal fluids often comprises concentrating and cooling steps, which increases the risk of silica scaling formation. However, existing silica removal strategies do not consider the impact on raw material extraction. In this study, the applicability and element-selectivity of three silica removal techniques (seed-induced, lime and caustic precipitation) were tested in batch experiments using synthetic and naturalgeothermal fluid samples. Increasing the pH-value to 10.5 and the Ca/Si ratio > 1.25 was found to mitigate silica scaling effectively via formation of calcium-silicate-hydrate phases (C-S-H phases). The developed silica removalprocess does not affect the raw materials and is therefore suitable for brine mining purposes.
Lithium extraction from high Mg/Li brine is a key technical problem around the world. Based on the principle of rocking-chair Lithium-Ion Batteries, cathode material LiMn2O4 is applied to extract lithium from brine, and a novel lithium-ion battery system of “LiMn2O4 (anode)|supporting electrolyte|anionic membrane|brine|Li1−xMn2O4 (cathode, 0<x<1)” is constructed. Gratifyingly, this system has strong adaptability for different brines. Concretely, for treating a low Li⁺ brine, the Mg/Li declined from 147.8 in brine to 0.37 in obtained anolyte and the Li⁺ in anolyte concentrated to 1.2 g·L⁻¹. For treating a high Li⁺ brine, the Mg/Li ratio decreased from the initial 58.8 in brine to 1.7 in obtained anolyte, the rejection rate of other impurities such as Mg²⁺, SO4²⁻ and B2O3 exceeded 97.8% and the Li⁺ recovery in brine could reach 83.3%. Furthermore, the dissolution rate of manganese per cycle is <0.077% and the intercalation capacity maintained 91% of the initial intercalation capacity after 100 cycles. Therefore, the electrochemical separation system introduced a new perspective for the lithium industry, which shows a high selectivity of lithium, great stability environmentally friendly.
Over the past few decades, the demand for lithium resources has increased significantly with the rapid development and extensive application of lithium-ion batteries. Extracting lithium from salt lake brine is of significance because of its abundance in brines. Numerous endeavours have addressed the challenges of magnesium/lithium separation from salt lake brines having high Mg/Li ratios with the aim of efficiently and sustainably recovering lithium resources. This review focuses on the latest advances in magnesium/lithium separation and lithium recovery from salt lake brines, including extraction, adsorption, membrane, and electrochemical methods as well as reaction-coupled separation technology. The features and adaptabilities of various methods are analysed from the viewpoint of the chemical structures of related materials, reaction mechanisms, properties, and applications. Among the available techniques, adsorption methods have great potential to be widely used. However, membrane methods have attracted attention owing to their low energy consumption and high separation rates; the advantages and limitations of nanofiltration, electrodialysis, bipolar membranes, and membrane capacitive deionisation are therefore summarised in this review. As representative electrochemical methods, the lithium ion capturing system and the rocking-chair battery system are reviewed, and the roles of various electrode materials in lithium recovery are analysed. Recently, reaction-coupled separation technology has emerged as an advantageous method for magnesium/lithium separation and lithium extraction. The ability of this technology to realise highly efficient magnesium/lithium separation while simultaneously preparing high-value magnesium-based functional materials from magnesium resources is discussed. The development of such methods that can comprehensively utilise the magnesium and lithium resources in salt lake brine is essential for resource sustainability.
Due to the abundant reserves and increasing demand, the extraction and separation of lithium from salt-lake brines have attracted great interest worldwide. This review aims to summarize the major developments in lithium recovery from brines, starting from an overview of lithium demand and consumption, available resources and processing methods, and challenges of processing brines, followed with the advancements in solvent extraction, ion-sieve adsorption, electrochemical approaches, and membrane technology, successively. The paper focuses on the principles, mechanisms, operations, and comparison of the various approaches. Other promising techniques, such as the modification of ion-sieves, rocking-chair batteries, and liquid-membrane electrodialysis, also are discussed in the depth of mechanisms. These processes present excellent performance in the separation of Li ⁺ /Mg ²⁺ or Li ⁺ /Na ⁺ . Finally, insights into the directions and prospects of lithium extraction from brines are presented. It can be concluded that only by integrating the advantages of various recent technologies will it be possible to develop an efficient, low cost, environmentally sustainable, and scalable process for lithium extraction from brines.
The presence of silica in coal seam gas (CSG) reverse osmosis (RO) brine complicates the membrane distillation (MD) process due to silica polymerization and metal silicate formation at high water recovery. This study reported that direct contact MD (DCMD) of CSG RO brine at electrical conductivity (EC) of 17.8 mS/cm achieved 90% brine recovery (overall recovery of 95%) with distillate flux decline of 16%, and distillate EC of 15 μS/cm over 150 h of operation. A series of experiments were conducted using synthetic solutions to evaluate the effect of CSG RO brine water quality on silica fouling in DCMD process. Results showed that CaCO3 formation was fast and did not co-precipitate with dissolved silica, while magnesium and silica were co-precipitated as magnesium silicate compounds. Results also revealed that polymerized silica formed a non-porous layer on the membrane surface. This fouling layer not only significantly reduced distillate flux but also led to a dramatic increase of distillate EC. Further study on silica fouling mitigation suggested that rapid cooling and filtration/clarification could be adopted for removal of silica from MD brines containing high silica concentration. It also showed that disodium ethylenediaminetetraacetic acid (Na2EDTA) was effective to hinder the formation of CaCO3 and magnesium silicate in MD.
We report a three-stage bench-scale column extraction process to selectively extract lithium chloride from geothermal brine. The goal of this research is to develop materials and processing technologies to improve the economics of lithium extraction and production from naturally occurring geothermal and other brines for energy storage applications. A novel sorbent, lithium aluminum layered double hydroxide chloride (LDH), is synthesized and characterized with X-ray powder diffraction, scanning electron microscopy, inductively coupled plasma optical emission spectrometry (ICP-OES), and thermogravimetric analysis. Each cycle of the column extraction process consists of three steps: 1) loading the sorbent with lithium chloride from brine; 2) intermediate washing to remove unwanted ions; 3) final washing for unloading the lithium chloride ions. Our experimental analysis of eluate vs. feed concentrations of Li and competing ions demonstrates that our optimized sorbents can achieve a recovery efficiency of ~91% and possess excellent Li apparent selectivity of 47.8 compared to Na ions and 212 compared to K ions, respectively in the brine. The present work demonstrates that LDH is an effective sorbent for selective extraction of lithium from brines, thus offering the possibility of effective application of lithium salts in lithium-ion batteries leading to a fundamental shift in the lithium supply chain.
The Geysers, the world’s largest geothermal power complex, has been the subject of numerous books, articles, technical papers, theses, conferences, and workshops. As with Larderello, there is a visitor’s center complete with displays and artifacts depicting the history and development of the field, and the general public can tour a part of the field and see a power plant. It is impossible, and unnecessary, to recount here all of the details of The Geysers’ history; we will summarize the highlights and refer the interested reader to more complete documents.
A new multi-channel spiral-wound membrane distillation (MD) module with a membrane surface area of 27.5m² was developed, constructed and characterized. For comparison, a set of different conventional single-channel direct contact membrane distillation (DCMD) module prototypes is introduced and experimentally evaluated, as well. Furthermore, a comprehensive assessment on DCMD module design and operation as well as methods for comparative thermodynamic MD module evaluation has been conducted. The methodical core of this work specifically addresses an integrative method for the derivation of the thermal energy demand of DCMD systems, comprising specifications of the external heat recovery system. A new strategy for the optimization of energy demand in DCMD is identified, which aims on the formation of parallel temperature profiles by adjusting the flow streams on the evaporator and the condenser channel. Suitable methods for a comparative analysis of different MD performance results are suggested and fundamental MD specifications are derived and applied to evaluate a set of different DCMD prototypes. The methods involve the analysis of the permeate output rate, flux and thermal energy consumption with respect to feed flow rate conditions. The optimization of flux and thermal energy consumption is identified to rely on conflicting requirements, which cannot be satisfied at the same time. The optimal combination of flux and thermal energy consumption depends on the projected scenario and may not be identified by a technical assessment alone. Economic considerations must be included. As final outcome, a method of specifying MD results by a representation of flux versus thermal energy consumption is suggested in order to allow a meaningful evaluation and to achieve global comparability among different MD configurations and other thermal separation technologies.
Extraction of Lithium (Li+) from synthetically prepared sea bittern using di-2-ethyl hexyl phosphoric acid (D2EHPA) and tri-n-butyl phosphate (TBP) as organic extractants has been studied. The equilibrium studies conducted shows synergistic effect between D2EHPA and TBP. The equilibrium constant values for Li+, Na+ and K+ ions were found to be 95.4×10−5 m3/kmol, 4.6×10−5 m3/kmol and 3.69×10−5 m3/kmol respectively. Hollow fiber supported liquid membrane experiments with low concentration of Li+, Na+ and K+ ions in feed phase, showed high flux for Li+ ions. However at significantly high concentrations of Na+ and K+ in feed phase, the flux of Li+ ions reduced. The model predictions were found in good agreement with the experimental data.
A better understanding of silica dissolution–precipitation reactions at high pH aqueous solutions allows for promotion of favorable (e.g., pozzolanic) reactions and mitigation of deleterious (e.g., alkali-silica) reactions in concrete. In this paper, the kinetics and products of silica glass dissolution are studied as a function of solution pH, temperature, and availability of calcium. It was observed that dissolution rate versus time increases linearly with pH and reaches a maximum at pH = 14, with slower dissolution at higher alkalinities. In solutions with similarly high pH, but saturated with portlandite, glass dissolution is significantly slower. This is due to formation of a dense, low porosity, and strongly bonded C–S–H layer on the surface of glass, which serves as a barrier against diffusion of OH− and alkali ions towards the substrate glass. This protective layer forms only when Ca is abundant and portlandite saturation can be maintained on a local scale.
The solubility of calcium hydroxide and the aqueous speciation of Ca(II) in alkaline medium at various temperatures and background electrolyte concentrations were characterized by solubility measurements applying ICP-OES and potentiometric detection methods. Contrary to suggestions from previous literature, the (dissolved) Ca(OH)2(aq) was found to be the dominant solution species above pH ∼ 13, although the well-known CaOH+(aq) is also formed to a much smaller extent. The solubility product, as well as the formation constants for the species CaOH+ and Ca(OH)2 were found to be (8.8 ± 0.2) × 10−5 M3, (1.5 ± 0.1) M−1 and (4.7 ± 0.1) M−2, respectively, at 25 °C, at 1 M ionic strength and expressed in terms of concentrations. The most important implication of this model is that the total concentration of the dissolved calcium(II) cannot be decreased below ca. 2 × 10−4 M at any base concentration, even if this is increased to the solubility limit of the caustic. This statement was further validated via precipitation titrations. The standard enthalpies and entropies of the reactions were also calculated from temperature-dependent solubility measurements.
Silica fouling patterns in a sodium–silica system and the effect of pH on residual dissolved silica concentrations are reported. The unique chemical affinity between sodium and silica (SO4) prevented silica scale deposition on the membrane surface during reverse osmosis (RO) desalination. It was found that high concentrations of sodium in solutions depressed silica solubility to 81–84 mg L−1 for a maximum NaCl salinity of 60–65 g L−1. Using a range of membrane examination techniques, it was found that no silica scale formed on the RO membrane surfaces from NaCl solutions free from cations such as Ca, Al and Fe. This was considered to be the result of sodium ions acting as a barrier between polymeric silica and the membrane surface.
This paper is the first to present the main geochemical characteristics of the native brines collected from all the geothermal wells penetrating the granite basement underlying the sedimentary cover, in the Upper Rhine Graben. These deep wells (from 2580 to 5000 m) were only drilled in four geothermal sites (Soultz-sous-Forêts and Rittershoffen in France; Landau and Insheim in Germany). The Na–Cl geothermal brine samples collected from the granite returned TDS values ranging from 99 to 107 g/l with pH values close to 5, along with Cl and Br concentrations and δD, δ18O and δ34S values that indicate a multiple origin with mixing between primary brine formed by advanced evaporation of seawater (probably until the stage of halite precipitation) and dilute meteoric water, plus contributions from halite dissolution following successive marine transgression-regression cycles from the Triassic to the Oligocene. Chemical, isotopic and gas geothermometers indicate concordant reservoir temperatures close to 225 ± 25 °C for all the fluids, even though the maximum temperature so far measured on site is 200 °C. An exhaustive literature review has indicated that only the geothermal brine from the deep Cronenbourg well (2870 m) ending in the Buntsandstein has similar chemical and isotopic compositions (apart from Br and Ca) to the fluids from the granite, with an identical estimation of reservoir temperature from geothermometry. Geothermal brine from the deep Bruchsal well (2540 m), drilled down to the junction of the Buntsandstein and the Saxo-Thuringian formations, has a higher TDS value (120–125 g/l) with its chemical and isotopic compositions giving a lower estimation of reservoir temperature (190 ± 25 °C). By contrast, geothermal brine from the Bühl well (2655 m) ending in the Buntsandstein has an even higher TDS value of about 201 g/l and a lower temperature-at-depth estimation of 110 ± 25 °C, close to the temperature measured on site (115 °C). The above results indicate that the geothermal fluids collected from the granite probably originate from Triassic sedimentary formations located at great depth (≥ 4 km) with temperatures close to 225 ± 25 °C in the centre of the Rhine Graben, but that their different TDS and Cl/Br values reflect the presence of several distinct geothermal reservoirs. Many discrepancies due to high-temperature water-rock interactions are revealed on comparing the chemical and isotopic compositions of the hot brines with those of cooler brines from Bühl and the Landau Eocene–Oligocene oilfield wells, among others. The hottest brines are much enriched in K, Ca, SiO2, Li, Rb, Cs, As, Sr, Ba, Mn, Nd, U and in metals such as Zn, Pb, Cu, Co, Cd, Sb, but are depleted mainly in Mg, SO4 and B and have much lower isotopic Li and B signatures. The He isotopic signatures of the gases associated with these fluids (R/Ratm. = 0.128 at Bruchsal and 0.252 at Insheim) confirm that the thermal anomalies are mainly crustal and not mantle-derived (1.46% and 2.88% of mantellic He, respectively, for the two sites). Thus it is concluded that the thermal anomalies are associated mainly with the convective circulation of hot fluids along probable NE–SW faults between the graben's deep sedimentary centre and the fractured granite basement at its edges. Moreover, the western part of the Upper Rhine Graben (the Landau, Insheim, Soultz, Rittershoffen and Cronenbourg sites) seems to be hotter than the eastern part (Bruchsal and Bühl). According to the U-Th isotope system, the minimum transit time of these deep geothermal brines would be about 1000 years.
A model for the CaO-SiO2-H2O system at 25°C is proposed, and based upon this, more complex systems including the effect of SO42-, Cl-, CO32-, Na+ and K+ on phase relations and solubilities in the title system have been calculated by thermodynamic modelling. At sea-water concentrations of NaCl, mixed sea-water-pore fluid compositions enhance the solubility of calcium from Ca(OH)2 and C-S-H but do not otherwise affect the stabilities of these phases. Carbonate and sulfate, on the other hand, react strongly with cement substances both with and without sodium being present; the complex solubility and reaction paths are quantified. Comparison of calculated reactions with literature data are made where possible; generally good agreement is obtained.
Geothermal power plants use geothermal fluids as a resource and create waste residuals as part of the power generation process. Both the geofluid resource and waste stream are considered produced fluids. The chemical and physical nature of produced fluids can have a major impact on the geothermal power industry and influence the feasibility of power development, exploration approaches, plant design, operating practices, and reuse/disposal of residuals. In general, produced fluids include anything that comes out of a geothermal field and must subsequently be managed on the surface. These fluids vary greatly, depending on the reservoir being harnessed, plant design, and life cycle stage in which the fluid exists, but generally include water and fluids used to drill wells, fluids used to stimulate wells in enhanced geothermal systems, and makeup and/or cooling water used during operation of a power plant. Additional geothermal-related produced fluids include many substances that are similar to waste streams from the oil and gas industry, such as scale, flash tank solids, precipitated solids from brine treatment, hydrogen sulfide, and cooling-tower-related waste.
The paper presents investigations on the process performance of different membranes with and without backing structure in direct contact membrane distillation. Influences of backing structures and their orientation are identified. An integrated membrane and backing model was developed. Laminates with different backing designs were examined over a wide range of operating conditions and compared to results for the same membranes without backing. Experimental results and model predictions for flux and thermal efficiency are compared. The model predictions agree well with the experimental results. An influence on the effective area for diffusion, an increase in effective diffusion path length in the membrane and the formation of a complex network of thermal resistances are considered to be the main effects, leading to a significant reduction in process performance due to backing structures. The backing was identified to be one of the key components for further improvement in MD applications. An integrated assessment of membrane properties in combination with backing structures was carried out by analysing membranes with different thicknesses and different pore sizes. The experimental observations show good agreement with theoretical considerations. A combined analysis of specific flux and thermal efficiency leads to comprehensive understanding of the process and its potential for optimisation.
Hydraulic and hydrochemical data from several hundred wells mostly drilled by the oil and gas industry within the four deep carbonate and siliciclastic reservoirs reservoirs of the Upper Rhine Graben area in France and Germany have been compiled, examined, validated, and analyzed with the aim to characterize fluids and reservoir properties. Due to enhanced temperatures in the subsurface of the Upper Rhine Graben the present study on hydraulic and hydrochemical properties has been motivated by an increasing interest in deep hydrogeothermal energy projects in the Rhine rift valley.The four examined geothermal reservoir formations are characterized by high hydraulic conductivity reflecting the active tectonic setting of the rift valley and its fractured and karstified reservoirs. The hydraulic conductivity decreases only marginally with depth in each of the reservoirs, because the Upper Rhine Graben is a young tectonically active structure. The generally high hydraulic conductivity of the reservoir rocks permits cross formation advective flow of thermal water.Water composition data reflect the origin and hydrochemical evolution of deep water. Shallow water to 500 m depth is, in general, weakly mineralized. The chemical signature of the water is controlled by fluid-rock geochemical interactions. With increasing depth, the total of dissolved solids (TDS) increases. In all reservoirs the fluids evolve to a NaCl-dominated brine. The high salinity of the reservoirs is partly derived from dissolution of halite in evaporitic Triassic and Cenozoic formations, and partly from the fluids residing in the crystalline basement. Water of all four reservoirs is saturated with respect to calcite and other minerals including quartz and barite.This article is protected by copyright. All rights reserved.
Scaling formation in surface installations of geothermal power plants can substantially affect power production by impairing heat transfer and reducing pipe diameters. In addition, the mineral deposits can incorporate naturally occurring radioactive nuclides into the crystal lattice during precipitation and have to be regarded as a potential hazard to health and environment. A profound understanding of formation mechanisms should facilitate the prevention of scaling in the future. Therefore fluid samples and scalings from the geothermal power plant at Soultz-sous-Forêts were investigated in detail. The fluid shows a total salinity (TDS) of 92 g/l and can be classified as Na-(Ca)-Cl-type. Considerations of the saturation state reveal a slight oversaturation with respect to barite (BaSO4) and celestine (SrSO4). X-Ray diffraction measurements together with scanning electron microscopic observation reveal that the scalings consist of barite-celestine solid solution ((Ba, Sr)SO4) interlayered with very fine layers of galena (PbS). The mineralogical composition was confirmed by X-ray fluorescence analysis showing a bulk composition of Ba (31.7–34.6 %), Sr (10.8–12.1 %), Pb (6.2–12.4 %) and S (13.1–14.5 %) for the sulfates, and Pb (66.6 %) and S (11.7 %) for the sulfidic part of the scalings. Other metals/metalloids like Sb (5.6 %), Cu (4.2 %), As (2.3 %) and Fe (2.0 %) were found to be present in minor amounts in the sulfides. Sulfur isotope studies show strong fractionation between the sulfate (δ34S =+15 ‰) and sulfide (δ34S = –12 ‰) phases. This indicates that bacterial sulfate reduction occurs, initiating sulfide precipitation from sulfate-rich fluids. The layered structure of the scalings can be correlated well with the operation state of the plant. Accordingly, sulfate layers precipitate under regular operation conditions, whereas sulfides were formed during start and shut-off phases of the plant.
This study investigated the silica scaling and cleaning behavior in forward osmosis (FO) and how it compared with that in reverse osmosis (RO). The comparison between FO and RO modes shows that, under the hydrodynamic conditions tested, the flux decline rates under silica scaling are very similar in the two modes, but the flux recovery is close to 100% in the FO mode while it is only around 80% in the RO mode. Cellulose acetate (CA) and polyamide (PA) membranes were used to study the effects of membrane materials on silica scaling and cleaning. It is found that the flux decline rates for both membranes are similar, but the flux recovery of the CA membrane is 30–40% higher than that of the PA membrane. AFM force measurements indicate that membrane surface roughness increases the adhesion force between the PA membrane and a silica gel layer, significantly decreasing the cleaning efficiency of the PA membrane. Results from dynamic light scattering and energy-dispersive X-ray spectroscopy indicate that silica scaling is initiated as monosilicic acid deposits on the membrane surface, followed by polymerization/condensation that forms an amorphous silica gel layer at the interface between the membrane and silica particles.
Solubility of quartz at depth is the major control on the amount of silica in solution in hot spring pools. Hot waters ascending rapidly to the surface become supersaturated with respect to quartz because of rapid cooling, separation of steam, and sluggish deposition of quartz and other crystalline SiO 2 phases. The silica content of boiling water discharged at the surface can be used to estimate underground temperature of last equilibrium with quartz, provided correction is made for steam forming during solution ascent. Using such correction, curves are presented showing dissolved silica measured in water discharged at the surface versus underground temperatures of last equilibrium with quartz. The method was applied to three wet-steam wells, and good agreement was obtained between the estimated and measured maximum temperature at depth.
In order to assess the current status of international geothermal power generation, the author has reviewed the Country Update (CU) papers submitted to the World Geothermal Conference 2000 in Japan from nations generating or planning to generate electricity. Salient facts in these papers have been synthesized and summary descriptions of geothermally-related activities written. Finally, following a brief discussion, conclusions are drawn and appropriate tables and graphs presented. The CU reviews revealed that: (1) geothermally-fueled electric power is being generated in 21 nations as of February 2000; (2) the installed capacity has reached 7974 MWe, which is a 16.7% increase since 1995; the total energy generated during the last 5 years has been at least 49,261 GWh; about 1165 wells more than 100 m deep have been drilled, and at least 13,621 person-years of professional geothermists’ time has been expended in the nations that reported this statistic.
The solubility of calcite at 10°, 25° and 60°C and at CO2 partial pressures of ∼ 1 kPa was investigated in the systems NaClC̄aCO3C̄O2H̄2O, KClC̄aCO3C̄O2H̄2O, CaCl2C̄aCO3C̄O2H̄2O, NaClC̄aSO4C̄aCO3C̄O2H̄2O and KClC̄aSO4C̄aCO3C̄O2H̄2O up to high ionic strenghts. Experimentally the total carbon dioxide content, total alkalinity and total Ca content in the solutions were measured and correspond to a calcite solubility in the range of . The evaluation of the Ca2+ and CO2−3 activity coefficients with Pitzer equations in the system NaClC̄aCO3C̄O2H̄2O at 25°C yields a mean value of pKsp(calcite) = 8.47 ± 0.09 which is in good agreement with literature data. A comparison between measured and calculated data, using the geochemical code PHREEQE, shows in the system NaClC̄aCO3C̄O2H̄2O relatively small deviations in comparison with the other solutions.
The Brönsted–Guggenheim–Scatchard Specific Ion Interaction Theory (SIT) has been employed for the pKw values of highly concentrated aqueous solutions of NaCl (Im≤6.00 mol kg−1), KCl (Im≤4.57 mol kg−1), CsCl (Im≤10.02 mol kg−1), KBr (Im≤4.71 mol kg−1), KI (Im≤6.96 mol kg−1), NaClO4 (Im≤13.66 mol kg−1), (CH3)4NCl (Im≤12.82 mol kg−1) and NaCF3SO3 (Im≤6.41 mol kg−1) at 25 °C. No systematic deviation from linearity was observed at very high ionic strengths (in some cases up to 10 mol kg−1). The intercept of the SIT plots, pKw0 (even with the inclusion of data points at the highest ionic strength) was found to be 14.00±0.04. Systematic downward deviation from linearity can only be identified in the I(m) >6 mol kg−1 range for NaClO4 and (CH3)4NCl containing systems (i.e., background electrolytes that are thought to be inert or “non-interacting”). Δɛ values obtained as the sum of ɛ(OH−,M+) and ɛ(H+,A−) calculated from the osmotic coefficients of HA and MOH solutions are always somewhat larger than those determined from the linear sections of our SIT plots for the given MA salt. The specific ion interaction coefficient ɛ(OH−,(CH3)4N+) has been estimated and, as expected for a non-complexing cation, it was found to be significantly larger, than those obtained for the other alkaline metal ions studied. On the basis of these results, it is possible that linear SIT behavior holds for equilibria other than the autoprotolysis of water, up to very high, i.e., hydrometallurgically relevant ionic strengths.
Increasing demand for lithium metal is expected to rise above the current production levels. Most lithium production is currently from mining and recovery of pegmatite ores. Recent research has emphasized recovery from brine sources such as geothermal water and seawater. A novel liquid-membrane-extraction process is investigated here for the recovery of lithium metal from these natural resources. Different carriers and combinations of carriers were tried for lithium selectivity. A carrier combination of LIX54 (main component is α-acetyl-m-dodecylacetophenone) and TOPO (tri-octyl phosphine oxide) had a synergistic effect for lithium extraction and was found to be most effective. This combination was used to extract lithium in a supported liquid membrane (SLM) process. Variables considered were pH, carrier concentrations, initial lithium concentration, type of organic solvent and stripping phase, and presence of sodium and potassium ions in the feed and flow rates of both aqueous phases. The optimal extraction efficiency of the system was higher than 95% for a model feed solution containing Na+, K+, and Li+ at pH greater than 12.5. The permeability of the system was maintained at a constant value for a maximum period of 2 days and dropped below 50% after 4 days. Empirical mathematical models for lithium extraction were derived from the results of SLM experiments.
Gelation of strongly basic silico−alkaline solutions was promoted by appropriate additions of calcium ions. The structure of the aggregates formed in the precursor sols and the resulting gels were studied, within a wide length scale, using small-angle X-ray, small-angle neutron, and elastic light scattering. The study of the kinetics of aggregation was performed in situ. The experimental results demonstrate that gels are composed of aggregates exhibiting a fractal structure, large particles formed in the solutions just after calcium addition and, in some cases, small primary particles remaining in the solution phase. The structural features of the gels are strongly dependent on the concentration of calcium ions. Reaction limited aggregation and diffusion-limited aggregation of primary silicate species are the predominant mechanisms of aggregation and gel formation in solutions with low and high calcium concentration, respectively.