Leiting ShenCentral South University | CSU · School of Metallurgy and Environment
Leiting Shen
Doctor of Engineering、Science(Technology)
About
65
Publications
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Introduction
Leiting Shen is an Associate Professor in the School of Metallurgy and Metallurgy, Central South University. Dr. Shen does research in Nonferrous Metallurgy and its Cleaner Production, Recycling of Critical Metals, and Thermodynamics of Aqueous Solutions. His current projects are "Low-carbon and Green Extractive Metallurgy of Tungsten and Molybdenum",
"Thermodynamic modelling of aqueous solution to enclosed recycle and scaling prevention", and "Recycling of Critical Metals".
Additional affiliations
June 2017 - June 2019
September 2015 - June 2019
September 2013 - June 2015
Publications
Publications (65)
Tungsten, as a strategic and critical raw material, has a wide range of industrial applications, due to its remarkable physical and chemical properties and the difficulty in finding a viable substitution. Tungsten extractive metallurgy produces the intermediate product from tungsten raw materials, intrinsically linking to the tungsten industry acro...
Rhenium is a scarce and highly important metal, which is widely used in high-temperature superalloys and platinum-rhenium catalysts due to its unique physicochemical properties. The substitution of rhenium in its applications is very limited, and there is no suitable substitute without losing essential performance. Furthermore , global extractable...
Calcium sulfate is one of the most common inorganic salts with a high scaling potential. The solubility of calcium sulfate was modeled with the Pitzer equation at a temperature range from 273.15 to 473.15 K from published solubility data, which was critically evaluated. Only two Pitzer parameters, β⁽¹⁾ and β⁽²⁾, with simple temperature dependency a...
To directly obtain solution of (NH4)2WO4 instead of Na2WO4 is the key for developing a cleaner technology of ammonium paratungstate production. In this paper, ammoniacal ammonium carbonate solution was adopted for leaching tungsten from the converted product, a mixture of H2WO4 and CaSO4 obtained by treating scheelite with sulfuric acid. The resear...
Copper slag containing fayalite as the main mineral is normally pretreated by reduction roasting for iron extraction through magnetic separation, and the particle size of iron grain affects iron recovery. The growth kinetics of iron grains in fayalite during reduction roasting were systematically studied in this work. Results showed that the iron g...
Samarium is a rare earth element that exhibits variable valence states of + 2 and + 3. In this work, we present the reduction products obtained through calciothermic reduction of SmF3 at various molar ratios of Ca to SmF3. The crystal structure, morphology, elemental distribution, and chemical valence of the reduction products were characterized us...
Bayer vanadium sludge (BVS), discharged during the Bayer alumina production, is a promising secondary resource for the supply of vanadium. The previous studies found that vanadium can be selectively extracted from BVS in the form of Ba3(VO4)2 using BaCO3 and then be leached in NH4HCO3 solution. However, a large liquid-to-solid ratio is necessary du...
Recovering fluoride from industrial alkaline solutions will benefit the environmental protection and improve product quality. This paper presented a novel approach to fluoride recovery by precipitating the coarse NaF from sodium aluminate solution. The equilibrium concentration of fluoride ion in the sodium aluminate solution was first presented as...
Gibbsite-type bauxite is the main material for alumina extraction by Bayer process globally, while the iron in red mud is difficult to use for the high alumina content. Therefore, the efficient separation of iron and alumina is the premise for the resource utilization of red mud. In this work, the separation of iron and alumina in red mud containin...
Preparation of high modulus solution and high Al/Si residue via leaching SiO2 is a key for large amount utilization of coal gangue based on ferric oxide assisted roasting – alkali leaching silica process. This work focuses on leaching mechanism of SiO2 in activated kaolinite clinker with low modulus sodium silicate solution. The results show that t...
Opal (amorphous silica, SiO2·nH2O), a solid waste byproduct of the alkaline extracting alumina from coal fly ash, exhibits strong adsorption properties and is a secondary/clay mineral in the soil. Combining opal with sand to construct opal/sand aggregates for desertification soil remediation holds the potential for large-scale ecological disposal....
Multi-channel exploitation and utilization of lithium-bearing resources may be the future sustainable development trend of the lithium industry. Lithium-rich bauxite flotation tailings are a potential lithium resource. This study proposed a green and effective lithium extraction process employing sodium bicarbonate solutions to leach lithium-rich b...
Coal fly ash (CFA) is an increasingly prevalent byproduct that necessitates more resourceful and eco-friendly processing methods. Extracting aluminum from CFA is a crucial aspect of promoting sustainable development in the alumina industry. In this paper, a technique for comprehensive extraction of silica and alumina from circulating fluidized bed-...
Efficient removal of silica is the key to alumina extraction from coal fly ash (CFA) by the Bayer process, due to the easy formation of sodium aluminosilicate hydrates during alkaline digestion. Considering the main mineral of well-crystallized mullite in CFA, mechanical activation was used in this work to improve the silica removal during reductio...
Bayer vanadium sludge(BVS) is a hazardous waste due to its high contents of V, P, As, and F. Full or partial utilization of this sludge could not only minimize the potential environmental risk but also promote resource recycling. In this work, a cleaner and cost-efficient process was proposed to selectively extract vanadium from BVS by employing Ba...
Due to the existence of large auxiliary material consumption, huge wastewater discharge, and high production cost in present tungsten extractive metallurgy practice, a novel technology featuring sulfuric acid conversion-ammonium salts leaching was proposed. Based on the complete conversion of tungsten minerals in sulfuric acid solution, this paper...
Large amounts of by-products, including coal gangue, circulating fluidized bed (CFB) slag, and coal fly ash (CFA), are generated during mining, washing and burning of high alumina coal (HAC). The stockpile of these by-products of HAC will cause the pollution of air, water and soil. Meanwhile, the unbalanced regional distribution of bauxite and alum...
Economical recovery of iron from high-iron red mud will benefit the comprehensive utilization of the mud, but current practice is restricted by poor magnetism and mutual embeddedness of ultrafine iron-bearing minerals. This work determined the effect of surface magnetization on iron recovery from ultrafine goethite and red mud by magnetic separatio...
Opal (SiO2·nH2O, amorphous silica), the by-product of alumina extraction from coal fly ash (CFA), has a strong adsorption capacity and is also an important component of clay minerals in soils. The combining of opal with sand to form artificial soils is an effective disposal strategy for large-scale CFA stockpiles and reduction of environmental risk...
A novel technology of hematite involved roasting-alkaline leaching-Bayer digestion process was proposed to extract alumina from high-alumina coal gangue (HACG), however the resource utilization of silica was not yet resolved. In this work, the alkaline leaching behavior of silica solid solutions in the product obtained by roasting the mixture of HA...
An understanding of the mechanisms of reactive Al and AlN in a sodium aluminate solution contributes to the safe and effective utilization of secondary aluminum dross (SAD). This study demonstrates that the slurry temperature increased exponentially with an increase in the SAD dosage. Synergistic kinetic phenomena in the form of a large dosage and...
Effective enrichment of organics by foam flotation will notably contribute to the removal of organics from the Bayer liquor. The present study shows that the removal efficiency increased with increasing concentration of sodium laurate (SL) and sodium stearate (SS). Over 29% SS removal with a concentration ratio of 2.92 was obtained from the Bayer l...
This paper systematically investigated the leaching behavior of bauxite lithium-rich beneficiation tailings in caustic solution, together with their phase and morphological changes. The main chemical compositions (mass percent) of bauxite flotation tailings were 40.56% Al2O3, 34.00% SiO2, 4.34% K2O, 3.31% TiO2, 1.83% Fe2O3, 0.37% MgO, and 0.59% Li2...
Rich foam is often formed in Bayer liquors, providing a promising short green process for the removal of organics by foam flotation. In this study, foam flotation of sodium oxalate (SO), sodium benzoate (SB), sodium citrate (SC), and sodium stearate (SS) was investigated using sodium dodecyl sulfate (SDS) as a frother and collector in a synthetic s...
The properties of low-modulus (m≤1) sodium silicate and pre-desilication solutions in alkali systems were studied by measuring their electrical conductivity, viscosity, and surface tension. The results show that the property of high concentration pre-desilication solution is similar to that of sodium silicate solution. The electrical conductivity o...
This paper describes a novel process, hematite involved roasting − alkaline leaching − Bayer digestion, to extract silica and alumina from high-alumina coal gangue (HACG). The phase transformations during roasting were investigated through X-ray diffraction, X-ray photoelectron spectroscopy, scanning electronic microscope, and energy-dispersive spe...
Aluminum-anodizing sludge (AAS), generated during the treatment of acidic waste-water in aluminum-anodizing process, is a kind of solid waste usually stockpiled due to low utilization. The recovery of aluminum and calcium from AAS through physicochemical process was systematically investigated in this paper. Phase analysis of AAS indicates that the...
Lithium is one of the secondary mineral elements occurring in bauxite. The behavior of lithium-bearing bauxite in the digestion process was investigated, and the effect of digestion conditions on the extraction rates of lithium was studied. The results demonstrate that the mass ratio of the added CaO to bauxite, the KOH concentration, and the diges...
Hydrogen can be used as an energy carrier for renewable energy to overcome the deficiency of its intrinsically intermittent supply. One of the most promising application of hydrogen energy is on‐board hydrogen fuel cells. However, the lack of a safe, efficient, convenient, and low‐cost storage and transportation method for hydrogen limits their app...
Iron recovery from copper slag generated during copper production by the pyrometallurgical method has been widely investigated to achieve resource utilization. Liberation and enrichment of metallic iron from reductively roasted copper slag were explored in this work. Results show that metallic iron, quartz solid solution, and cristobalite solid sol...
Copper slag (CS) with Fe-bearing fayalite and magnetite is the main waste generated during the pyrometallurgical processing of metallic copper. In this paper, the solid-state reduction kinetics of fayalite with and without addition of 10 wt.% metallic iron were studied using the isothermal method. The phase transformation of fayalite was verified b...
The adsorption–desorption behavior of La3+, Eu3+, and Y3+ by Mg(OH)2-pretreated TP207 resin in sulfate solution has been investigated. The effects of the reaction duration, pH value, flow rate, and adsorption mechanism were studied in detail. The results show that the highest adsorption capacity is obtained at solution pH of 4.0. The adsorption aff...
To prevent scaling and to recycle aqueous solutions in industrial processes, the thermodynamic properties of the CaSO4–H2SO4–H2O system are studied by thermodynamic modeling with the Pitzer model. The published solubility data of calcium sulfate hydrates in sulfuric acid solutions were collected and reviewed critically. Then, the CaSO4–H2SO4–H2O sy...
Improving metal-slag separation in pyrometallurgical processes is increasingly important. Due to the harsh conditions, direct observations of the molten phases behavior in the settler of the Outotec Flash Smelting Furnace (FSF) are not possible and the ways to improve metal settling can only be studied by simulation and modeling. This study focuses...
Fluoride molten-salt electrolytic slag is an important secondary resource for recovery of rare earth elements. In this study, the recovery of rare earths from this source was systemically investigated using borax roasting followed by hydrochloric acid leaching. Increasing the roasting temperature, reaction time and borax dosage promoted the recover...
Tungsten is considered as a strategic and critical raw material, due to its remarkable physical and chemical properties, wide industrial applications and non-substitutability. Ammonium paratungstate is the main intermediate product extracted from tungsten ores with metallurgical processes, intrinsically linking to the tungsten industry across all s...
The reaction behaviors of silicate species in (NH4)2WO4−(NH4)2CO3−NH3−H2O system are crucial to developing a green
manufacture technique for ammonium paratungstate. In order to efficiently remove silicon from the system, the reaction behaviors of
silicate species were systematically investigated by thermodynamic analysis. The thermodynamic analysis...
The thermodynamics of tungsten ore decomposition in mineral acid and alkaline solutions were studied. The published thermodynamic data of tungsten minerals were collected and assessed. The Gibbs energies of CaWO4 (−1538.43 kJ/mol), FeWO4 (−1053.91 kJ/mol), MnWO4 (−1206.08 kJ/mol), H2WO4 (−1003.92 kJ/mol), and Na2WO4 (−1455.58 kJ/mol, aq) at 25 °C w...
Complete conversion of scheelite in H2SO4 solution plays a key role in exploration of cleaner technology for producing ammonium paratungstate. In this work, the factors influencing scheelite conversion were investigated experimentally to model its kinetics. The results indicated that the conversion rate increases with increasing temperature and red...
Complete wolframite conversion in sulfuric acid is significant for expanding the applicability of the sulfuric acid method for producing ammonium paratungstate. In this paper, the conversion of wolframite in treating a mixed wolframite–scheelite concentrate by sulfuric acid was studied systematically. The results show that the conversion of wolfram...
Questions
Question (1)
How to accurately determine the total content of carbon in ammonia-ammonium carbonate mixed solution? When I am doing the experiment, I find it is difficult to accurately determine the total contents of ammonium and carbon in the mixed NH3-(NH4)2CO3 solution, especially for the total carbon content. So I want to find a method to analyse their contents. Thanks~