Rafael Romero

University of Seville | US · Languages and Systems

In this work, the recovery of Cu from large waste printed circuit board (PCB) pieces by biogenic ferric sulphate at high solid to liquid ratio was studied. PCB parts were packed in a column and biogenic ferric was constantly recirculated. A high oxidation reduction potential (ORP) decrease was observed in ferric leaching due to ferric ion consumpti...

Mineralurgical and metallurgical processes generate a large amount of harmful residues. These wastes usually contain a considerable fraction of sulphides and a low percentage of target metals. Due to their characteristics, the main environmental issues concern the acid mine drainage generation and the release of metals. The bio-leaching of these ta...

In the present work, a two-stage biohydrometallurgical process for copper extraction from waste PCBs is developed. The main goal of this study is to check whether to separate the chemical leaching of copper with ferric iron from the regeneration of the leaching agent by bacterial oxidation of the ferrous iron is an efficient route for copper recove...

Water recycling is a common practice in sulphide ore processing plants by flotation. Inherent thiosalts accumulation in process water often causes efficiency drop and environmental issues for wastewater discharging. Passive and active depuration methods have been applied for thiosalts removal and bio-oxidation in packed bed bioreactors can be consi...

Nowadays sulphide ores exploitation is undergoing some troubles, which are hindering the treatment through traditional routes. Bulk flotation followed by a novel hydrometallurgical process can dodge these difficulties. In this work, an integral hydrometallurgical process consists of two ferric leaching steps, followed by a hot brine leaching stage,...

Economic and environmental imperatives force the metallic sulphide processing industry to re-use liquors that normally contain thiosalts; this processing entails difficulties in operation control and losses in metal-extraction performance. Bio-oxidation presents a promising option for thiosalt removal. Hitherto, this method has been tested to treat...

Flotation tailing is a problematic mining waste, because contains sulphides that exposed to oxidising conditions generate acidic drainage and the subsequent metal mobilisation. In this study, a flotation tailing produced within an integral process for the treatment of polymetallic sulphide ores is cleaned and valorised seeking a better use of natur...

A novel procedure to recover lead, silver and gold from polymetallic sulphide ores, cleaner than the traditional hydrometallurgical route (hot brine leaching), is proposed. This process consists of a biooxidation stage, where sulphides are oxidised by the action of extremophiles, followed by an acid washing and a citrate leaching in which lead is r...

Copper smelter flue dust is a residue, rich in zinc, originating from the pyrometallurgical process of copper, and constitutes a potential raw material for zinc production. In order to valorise this waste by hydrometallurgical processes, its leaching with sulphuric acid at constant pH is studied. Experimental conditions (temperature, pH, and pulp d...

BACKGROUND Cu is an indispensable natural resource for society, as its use is widespread and essential for many technologies. Consequently, worldwide production is around 18·10⁶ tn/year, and close to 25% is produced by bioleaching. Bioleaching enables Cu extraction from minerals in atmospheric conditions by virtue of microorganisms’ catalytic activ...

A novel process for the integral treatment of polymetallic sulphide ores is proposed. The process consists of a global flotation, two stages of ferric leaching, the first stage dissolves the sphalerite and the rest of secondary sulphides, and the second dissolves the chalcopyrite with a silver catalyst, and finally a brine leaching to recover lead...

Bio-oxidation provides an intriguing alternative to the treatment of mining effluents that contain polythionates. In this study, a mixed culture, isolated from a tailing pond, has been adapted to operational conditions (3.35 g/L of tetrathionate, pH = 2). An exhaustive study of the influence of temperature on the tetrathionate bio-oxidation in a we...

Oxygen is usually the limiting reagent in bio-leaching processes. For this reason, aeration is a key point to take into account when designing such processes, and the oxygen saturation concentration is an important variable to know. Currently, there is a lack of data or models to accurately predict the concentration at which oxygen saturates under...

Polythionates are formed by the incomplete oxidation of sulphide minerals in the grinding and flotation circuits, and particularly of those containing pyrite. Polythionate levels in the recycling water must be adjusted; otherwise, it can affect metal recoveries. The presence of different species, such as thiosulphate, trithionate, and tetrathionate...

Thiosalts are compounds commonly present in process plant liquor for the concentration of metal sulphide ores by milling and flotation. Since thiosalts are metastable species that are oxidized to sulphuric acid as an end product, they cannot be discharged nor recycled into the process. Therefore, the development of a cost-effective process for the...

In this paper, the purification of acid mine water and the treatment of electric arc furnace dust (EAFD) are integrated into one process with the aim of recovering the Zn content of both effluent and waste. Zinc recovery can reduce the cost of their environmental management: purified acid mine water is discharged after removing all metals; EAFD cea...

The characterization of mine waste, such as low-grade ores, tailings and dumps, requires the development of methods that predict the behaviour over time and the possible degradation and, consequently, the generation of acid water and the contaminating leachate production. The current predictive techniques are mainly based on static and dynamic leac...

The pathogenesis of Alzheimer Disease (AD) is characterized by accumulation of β-amyloid protein in the brain (in both soluble and insoluble forms) and by the presence of intracellular neurofibrillary tangles (NFTs), leading to neurotoxicity. The exact mechanisms whereby Aβ triggers brain alterations are unclear. However, accumulating evidence sugg...

The development of a nervous system is a key innovation in the evolution of metazoans, which is illustrated by the presence of a common developmental toolkit for the formation of this organ system. Neurogenesis in the Spiralia, in particular the Platyhelminthes, is, however, poorly understood when compared with other animal groups. Here, we charact...

Thiosalts are compounds generated in facilities for complex sulfide ores concentration, during the milling and flotation stages. Thiosalts are metastable species that are oxidized by complex reactions in series to give, eventually, sulfuric acid. As a result, water is acidified and has high oxygen demand therefore it cannot be discharged nor recycl...

Dithiocarb (diethyldithiocarbamate, DEDTC) belongs to the group of dithiocarbamates and is the main metabolite of disulfiram, a drug of choice for the treatment of alcohol dependence. Its therapeutic potential relays on its ability to create an unpleasant aversive reaction following the ingestion of alcohol, and this effect is usually accompanied b...

Photoreception is one of the most primitive sensory functions in metazoans. Despite the diversity of forms and components of metazoan eyes, many studies have demonstrated the existence of a common cellular and molecular basis for their development. Genes like pax6, sine oculis, eyes absent, dachshund, otx, Rx and atonal are known to be associated w...

During the last decade, the field of evolutionary developmental biology (evo-devo) has emerged as a major research discipline in modern biology and an essential approach to understanding evolutionary relationships in the animal kingdom. At the same time, planarians have become a useful and important model with which to address basic questions regar...

Disulfiram is an aldehyde dehydrogenase inhibitor used for the treatment of alcohol dependence and of cocaine addiction. It has been demonstrated that subchronic administration of disulfiram or N,N-diethyldithiocarbamate (DEDTC), the main derivative of disulfiram, to rats can produce central-peripheral distal axonopathy. However, few data regarding...

A stream of effluent from a mine tailings pond, containing zinc, ferrous ions and other metals, required treatment to prevent pollution and recover valuable metals. A solvent extraction (SX) process using Ionquest 290 as extractant was developed to recover the Zn from the effluent. Ferrous ions were bio-oxidized and removed by selective alkaline pr...

Two new species of the genus Microplana are described from the Iberian Peninsula. The new taxa are compared with congeneric species. Distributional records for two other European species, Microplana monacensis (Heinzel, 1929) and Microplana groga Jones et al. 2008, are presented and the presence of Microplana terrestris (Müller, 1774) is confirmed...

J. Neurochem. (2011) 117, 244–252. JNK3 is mainly expressed in the CNS and it plays a crucial role in neuronal death in several neurodegenerative diseases. By contrast, the isoforms JNK1 and JNK2 seem to be involved in brain development. The lack of Jnk3 confers neuroprotection, although mechanisms responsible are unknown. The present study analyze...

Few studies have examined the diversity of freshwater planarians in the Iberian Peninsula and Greece. We have searched extensively for specimens, mainly in the Iberian Peninsula, and have gathered information on their taxonomy and biogeography. Two new species of Dendrocoelum and six new species of Phagocata are described. We also review the status...

The formation of a through-gut was a key innovation in the evolution of metazoans. There is still controversy regarding the origin of the anus and how it may have been either gained or lost during evolution in different bilaterian taxa. Thus, the study of groups with a blind gut is of great importance for understanding the evolution of this organ s...

The flooded packed-bed bioreactor plays a major role in the field of applications of ferrous ion bio-oxidation. The pH is an important variable in the control of this type of reactor, upon which the functionality of biofilm depends.In the present work, five continuous flooded packed-bed reactors have been inoculated with mixed cultures (Acidithioba...

J. Neurochem. (2010) 114 , 1315–1322. Abstract The MAPK family is formed by extracellular signal‐regulated kinases p38 kinase and stress‐activated protein kinases (SAPK/JNK). There are three genes that encode for three JNK proteins. JNK3 is mainly expressed in the central nervous system and has been related to various processes in that tissue. Spe...

Ferrous iron bio-oxidation is negatively affected by the presence of heavy metals. Although the available information relates this phenomenon to purely biological aspects, it is contradictory with respect to tolerance levels, mechanisms and kinetics. This dispersion of results may be due to the empirical nature of the approaches which are based on...

The Silences of the Archives, the Reknown of the Story. The Martin Guerre affair has been told many times since Jean de Coras and Guillaume Lesueur published their stories in 1561. It is in many ways a perfect intrigue with uncanny resemblance, persuasive deception and a surprizing end when the two Martin stood face to face, memory to memory, befor...

Marine planarians were collected extensively from the Iberian Peninsula and Italy. As a result we provide new distributional records of six species of marine triclads, including the description of one new genus and species. The study increases substantially our knowledge of the distribution of this group of animals in Spain and reveals that even re...

Axonal degeneration has been described as the pathological hallmark of peripheral neuropathies induced by DEDTC. In addition, axonal damage has also been observed in the brain of mice treated daily with DEDTC along postnatal development, though with this experimental model there was observed to be axonal recovery after treatment, during the adultho...

Taurine is one of the most abundant free amino acids in the mammalian central nervous system, where it is crucial for proper development. Moreover, taurine has been related with epilepsy, as it can reduce or prevent seizures. It is also a neuroprotectant in other experimental conditions. Glial cultures were analysed to determine the changes in taur...

The main source of copper loss from a smelter is copper in discard slag. Slag can contain Cu in concentrations very much higher than those of many ores. Cu is present in slag entrained in very small drops of matte, white metal and blister copper occluded in fayalitic phase. In this work, the technical viability of the BRISA process, that is based o...

This paper studies the ferric sulphate leaching of converter slag (9% Cu) in order to recover Cu through a process in which bacteria regenerate the leaching agent. For this purpose, the effect of variables such as pulp density, ferric concentration, temperature and size particle have been investigated.As the Cu extraction is limited by the physical...

The pyrometallurgical production of copper generates slags, a residue with a significant content of this metal. Copper can be recovered from the slags by froth flotation after cooling, crushing, and grinding. The obtained Cu-concentrate is sent to the pyrometallurgical process. If grinding is not fine enough for efficient flotation, copper is lost...

The ability to report or modify the embryological processes in living embryos is pivotal for developmental biology research. Planarian embryology has experienced renewed interest as the genetic pathways that drive adult regeneration were found to be involved in the development of embryos. The major drawback to the study of planarian embryology is t...

Acid mine drainage (AMD) from mining operations is one of the most difficult environmental problems faced to the sulphide mining industry. AMD is a contaminated effluent that results from the oxidation of iron-sulphide minerals exposed to air, water and oxidising bacteria. This problem worsens after the mine is closed and abandoned. The Iberian P...

The oxidation of ferrous iron by ferrooxidant bacteria is a potential industrial process in the regeneration of ferric iron, in hydrometallurgical leaching operations and in the removal of H2S in combustible gases. Another field of application is the treatment of acid mine drainage waters. This work discusses about basic criteria for the selection...

In this work a biotechnology for the recovery of copper from slags is shown. This biotechnology is based on the BRISA process and consists of a dynamic leaching with ferric sulphate (ferric leaching stage), where copper is released from slags, and the biological regeneration of the oxidising agent from its reduced form biooxidation stage). The rege...

About 80% of the world’s Cu from ore originates in copper-iron-sulphide ores. Cu-Fe-S minerals are not easily dissolved by aqueous solutions, so the vast majority of copper extraction from these minerals is pyrometallurgical. The pyrometallurgical process involves smelting and converting stages, carried out in furnaces at temperatures higher than 1...

Following a failure of a tailing pond dam at mine in Andalusia, Spain, a huge effluent stream, that contained about 1 g/L Zn and significant amounts of Ferrous, ferric, calcium, copper, aluminium, and manganese cations has to be treated, to prevent pollution of a nature reserve. EGMASA, as the regional government environmental agency, suggested to...

Little is known about the taxonomy and distribution of terrestrial planarians on the Iberian Peninsula. Few studies have tried to investigate the local diversity of these animals, due to both their lack of economic interest and their low abun-dance. In this study we have made extensive searches and collections of terrestrial planarians from the Ibe...

Little is known about the taxonomy and distribution of terrestrial planarians on the Iberian Peninsula. Few studies have tried to investigate the local diversity of these animals, due to both their lack of economic interest and their low abundance. In this study we have made extensive searches and collections of terrestrial planarians from the Iber...

The indirect bioleaching of zinc and lead concentrates offers, in many cases, both economic and environmental advantages via lower cost and more environmentally friendly integrated processes than conventional technologies such as selective concentrates production and smelting or refining processes. The new developments for indirect bioleaching of z...

FIGURE 6. Microplana gadesensis. CRBA 443 - 444. Sagittal section through the head.

FIGURE 7. Microplana gadesensis. CRBA 443 - 444. A – B. Sagittal sections of the copulatory apparatus; anterior to the left.

FIGURE 1. Distributional records of autochthonous terrestrial planarians in the Iberian Peninsula. A. Iberian Peninsula excluding Catalonia. B. Catalonia. Numbers indicate the total number of localities in each area. Arrow points to the type locality of the three new species.

FIGURE 5. Microplana grazalemica. CRBA 438 - A 439. A. Sagittal reconstruction of the copulatory apparatus; anterior to the left. CRBA 440 - 442. B. Sagittal reconstruction of the copulatory apparatus; anterior to the left.

FIGURE 8. Microplana gadesensis. CRBA 443 - 444. A. Sagittal reconstruction of the copulatory apparatus; anterior to the left. CRBA 445. B. Sagittal reconstruction of the copulatory apparatus; anterior to the left.

FIGURE 2. Microplana aixandrei. Holotype. CRBA 435. A. Living animal. B. Sagittal section through the head. C. Sagittal section through front end. D – E. Sagittal sections of the copulatory apparatus; anterior to the left. F. Sagittal reconstruction of the copulatory apparatus; anterior to the left.

FIGURE 3. A. Diagrammatic transverse section through the pharynx of Microplana aixandrei showing the arrangement of the rows of longitudinal and circular muscles. B. Microplana grazalemica. Living animal. Scale bar 1 mm.

FIGURE 4. Microplana grazalemica. CRBA 438 - A 439. A – B. Sagittal sections of the copulatory apparatus; anterior to the left.

The technical viability of the BRISA process for copper concentrates consisting of mixtures of either chalcopyrite and secondary copper sulphides (chalcocite and covellite) or chalcopyrite and sphalerite was studied. The ferric leaching of six concentrates (different in origin, granulometric, chemical and mineralogical composition) was tested in th...

Presence of land planarians of the genus Microplana (Platyhelminthes, Tricladida, Terricola) in Montnegre-Corredor Park

The current treatment of copper ores containing atacamite and secondary copper sulphides consists of heap leaching, by the TL process. Copper recoveries by this treatment are very low (less than 50 % for operating times higher than six months). In order to improve the copper extraction yields, several treatment options are presented in this work, w...

The current treatment of copper ores containing atacamite and secondary copper sulphides consists of heap leaching, by the TL process. Copper recoveries by this treatment are very low (less than 50 % for operating times higher than six months). In order to improve the copper extraction yields, several treatment options are presented in this work, w...

The technical viability of the BRISA process (Biolixiviación Rápida Indirecta con Separación de Acciones: Fast Indirect Bioleaching with Actions Separation) for the copper recovery from chalcopyrite concentrates has been proved. Two copper concentrates (with a copper content of 8.9 and 9.9 wt.%) with chalcopyrite as the dominant copper mineral have...

Thiosalts are reduced sulphur species that are present in the liquid effluents of the sulphide flotation plants of any mining exploitation. This is due to the fact that the sulphur ion is partially oxidized in an alkaline medium and to the use of SO2 as a depressant agent. The conventional treatment that these effluents receive consists of neutrali...

The biogas generated in the anaerobic digestion of biodegradable substances consists of methane and carbon dioxide, with percentage variations that range between 55 and 75% and between 25 and 45%, respectively. In addition, hydrogen sulphide, ammonia and traces of gaseous organics are present in proportions less than 1%. Due to its methane content,...

The technical viability of the BRISA process (Biolixiviación Rápida Indirecta con Separación de Acciones: Fast Indirect Bioleaching with Actions Separation) for secondary copper sulphides has been proved. One concentrate and two ores with chalcocite and covellite as the dominant copper minerals have been leached with ferric sulphate at 12 g/L of fe...

In this paper, oxygen transfer in the ferrous iron biooxidation process in a packed-bed reactor is studied. The reactor consists of a polymethyl methacrylate column randomly packed with siliceous stone particles with inlets for liquid medium and air at the bottom from where they flood the reactor. The aim of this work is to determine the parameters...

The biooxidatíon of ferrous iron in solution has industrial applications in the regeneration of ferric iron as a leachíng agent for non-ferrous metallic sulphides and in the treatment of acid mine drainage. The aim of this work was the study of several variables (pH, temperature, particle size, bacterial support material and type of air distributor...

The biooxidation of ferrous iron is a potential industrial process in the regeneration of ferric iron, in hydrometallurgical leaching operations and in the removal of H2S in combustible gases. Another field of application is the treatment of acid mine drainage water. The aim of this work was the design of a continuous reactor for a high efficiency...

Two leaching systems have been investigated to recover copper from a mixed atacamite, secondary copper sulphides mineral: heap leaching and BRISA process. The mineral contains 3.13% Cu, 0.32% C1, a copper as sulphide/copper as oxide ratio of 1.75, and a composition of the different particle size fractions quite close to each other. The treatment of...

The biooxidation of ferrous iron in solution has industrial applications in the regeneration of ferric iron as a leaching agent of non-ferrous metallic sulphides and in the treatment of acid mine drainage. The aim of this work was the design of a continuous reactor for a high efficiency ferrous iron biooxidation. Basic criteria of design have been...

Simulation programs have been devel oped to study the effect of recycling the electric arc furnace dust leaching residues to the furnace. Residues from sulfuric acid and sodium hydroxide leaching have been tested. Results enable the furnace-leaching response to be defined in accord with the recycling rate and conditions for zero stabilization to be...

In this paper the biological ferrous iron oxidation in flooded packed bed reactors is studied. Bacterial oxidation of ferrous iron is a potential industrial process for the treatment of acid mine drainage and in the regeneration of ferric iron as a leaching agent in hydrometallurgical processes.The aim of this work is the development of a reactor c...

The Indirect Bioleaching with Effects Separation process (IBES process) has been applied to a chalcopyrite/sphalerite concentrate from Rio Tinto. In this paper the chemical stage of the process (ferric sulphate leaching) has been studied in agitated batch reactors. Two stages of ferric sulphate leaching are required at atmospheric pressure: primary...

The selection of the operating conditions of a continuous silver catalyzed IBES (Indirect Bioleaching with Effects Separation) process for a chalcopyrite–sphalerite concentrate from Rio Tinto is presented. The data generated from the batch tests have been used to estimate the operating parameters for the continuous system. In order to obtain metal...

The indirect bioleaching with effect separation process has been applied to a chalcopyrite–sphalerite concentrate from Rio Tinto. In this paper the biooxidation of the ferrous iron generated in the chemical stage (ferric sulphate leaching) and the recovery of the silver used as a catalyst have been studied. The ferrous iron in leaching liquors can...

Bioleaching of sulphide minerals is a hydrometallurgical process whereby the leaching of sulphides is catalysed by microorganisms get their energy for growth from oxidation of inorganic substances. From Them, Thiobacillus ferrooxidans has the ability to oxidize sulphur and sulphur compounds as well as ferrous iron in solution. In recent years, biol...

The kinetics of bioleaching of sulphide concentrates by Thiobacillus ferrooxidans can be improved by performing separately the two operations relating the two effects involved in the indirect contact mechanism, (1) chemical leaching and (2) biological oxidation of the Fe2+ produced in the chemical stage (IBES: Indirect Bioleaching with Effects Sepa...

Hydrometallurgical treatment of pyrite ashes, using acidic-oxidant low-cost leaching agents (like acidic mine waters), yields leaching liquors suitable for copper and zinc recovery. The leaching curves obtained show the dependence of the total extraction level and the liquor characteristics on the system used for pyrite roasting. Soluble copper and...

Some methods to obtain good yields in Au and Ag extraction from pyrite ashes by cyanidation are analyzed. Two essential factors exert a negative influence on the process: the cyanicide agent presence (especially soluble copper) and the residual sulfide without roasting, whose oxidation in an alkalne medium causes the appearance of reduction agents...