High-purity Carbonate Research Articles

PROSPECTS FOR CREATING A FULL CYCLE OF LITHIUM PRODUCTION IN KAZAKHSTAN – FROM ORE PROCESSING TO LITHIUM BATTERIES

Today, lithium is becoming a new strategic material capable of influencing the sustainable development of the world economy. The results of developments in the production of innovative electrode materials from lithium carbonate on the basis of domestic lithium-containing raw materials with the creation of a full cycle of the technological line of lithium production: from ores to modern lithium batteries are pesented. Analysis of the explored reserves, mineral and material composition of domestic spodumene raw materials and lithium-containing dumps of the Belogorsk GOK indicate the prospects and expediency of their development for the production of the ever-increasing needs of the world market for lithium materials. As a result, the sulfuric acid technology for obtaining high-grade lithium carbonate directly from spodumene was optimized, bypassing the stage of obtaining a technical grade product, in a single technological process for processing spodumene with a reduction in the number of technological operations, excluding the expensive operation of concentrating a lithium sulfate solution by stripping. An efficient technology of purification and post-treatment of technical lithium carbonate to battery quality of 99.95% has been developed, including the processes of causticization of technical lithium carbonate, ultrafiltration and ion-exchange sorption of a solution of lithium hydroxide, followed by precipitation of lithium carbonate by ammonium carbonate. Cathode materials - lithium iron-phosphate , obtained from high-purity lithium carbonate by aerosol pyrolysis (MAP) and the sol-gel method (SGM), showed good electrochemical characteristics. The end result is innovative electrode materials for modern LIBs with significantly increased capacity and stability. The practical implementation of a full cycle of technologies from lithium-containing raw materials to modern lithium batteries opens up prospects for the creation in Kazakhstan of a high-tech lithium cluster according to the Scheme: Spodumene ores → Lithium concentrate → Lithium carbonate → Lithium cathode materials → Batteries.

On the Production of Potassium Carbonate from Cocoa Pod Husks

Cocoa beans are found inside an outer husk; 60% of the cocoa fruit is the outer husk, which is a waste biomass. The husk cannot be used directly as a soil amendment as it promotes the fungal black pod disease, which reduces crop yield. The pods are segregated from the trees, and their plant nutrient value is wasted. This is particularly true for the small acreage farmers in West Africa. Cocoa pod husk is well suited to be used as a biomass source for electricity production. The waste ash is rich in potassium, which can be converted in various chemical products, most notably, high-purity potassium carbonate. This study reviews the information known about cocoa and cocoa pod husk, and considers the socio-economic implications of creating a local economy based on collecting the cocoa pod husk for electricity production, coupled with the processing of the waste ash into various products. The study demonstrates that the concept is feasible, and also identifies the local conditions required to create this sustainable economic process.

Recycling of spent lithium-ion batteries: Selective ammonia leaching of valuable metals and simultaneous synthesis of high-purity manganese carbonate

Recycling of spent lithium-ion batteries (LIBs) has drawn considerable attention in recent years, as an economic solution to the resource shortage. Selective ammonia leaching is recognized as an economical and environment-friendly method, yet it is difficult to separate and reuse the valuable metals from the leachate. In this study, we proposed an NH3–(NH4)2CO3-Na2SO3 leaching system to selectively recover the valuable metals from commercial LiNixCoyMn1−x−yO2 (NCM) and spent NCM. For single-stage leaching, 79.1% of the lithium, 86.4% of the cobalt, and 85.3% of the nickel were selectively leached under optimal conditions, and a mere 1.45% of the manganese was dissolved in the solution. The leaching process in the NH3–(NH4)2CO3-Na2SO3 system was consistent with the surface chemical reaction control model. For multistage leaching, almost all metals (98.4% of the lithium, 99.4% of the cobalt, 97.3% of the nickel) could be leached and a high-purity (>99%) MnCO3 product was simultaneously obtained. The introduction of CO32− not only led to the production of MnCO3 with wide application prospects, but also greatly reduced the consumption of the reducing agent. This study is thus beneficial for recycling of the valuable metals and synthesis of the MnCO3 product from the spent LIBs.

Recycling of mixed lithium-ion battery cathode materials with spent lead-acid battery electrolyte with the assistance of thermodynamic simulations

Based on the concept of recycling waste with waste, the mixed cathode materials of spent lithium-ion batteries were recycled with waste electrolyte from spent lead–acid batteries. With the assistance of thermodynamic simulations, the optimized recycling path of the mixed cathode materials was proposed and tested. A higher overall recycling ratio of valuable metals, that is, 94.9% of lithium, 94.5% of cobalt, 94.4% of nickel, and 95.5% of manganese, was achieved by replacing the oxalates/carbonates used in the precipitation process with sulfides and reducing the solubility of lithium carbonate in the lithium precipitation step at room temperature with ethanol. A higher ethanol-to-water ratio yielded a higher precipitation ratio of lithium until the ratio reached 5:1. High-purity lithium carbonate and cobalt (99.9%) were recovered as nanoparticles and nanoribbons, respectively, through precipitation using carbon dioxide in a solution with a 4:1 ethanol-to-water ratio and electrodeposition at E = −0.4 V in a traditional three-electrode system. Furthermore, the poisonous heavy metal (lead) was separated and stabilized as lead sulfide.

Processing of metallic bismuth for the production of bismuth compounds

ABSTRACT The hydrolytic processing of bismuth-containing nitrate solutions resulting in the production of high purity basic bismuth nitrate and carbonate, bismuth nitrate and bismuth oxide was studied. The developed technology is based on the oxidation of metallic bismuth followed by the dissolution of the obtained technical bismuth oxide in nitric acid and its purification from metal impurities by hydrolysis of Bi(NO3)3 in aqueous solution under alkaline conditions or with excess water to produce basic bismuth nitrate. The pilot-plant trials confirmed the viability of the developed technology.

Preparation of High-Purity Lithium Carbonate Using Complexing Ion-Exchange Resins

Sorption of a series of alkaline earth and nonferrous metals (Ca, Mg, Cu, Ni, and Zn) from lithium hydrocarbonate and chloride solutions onto ion-exchange resins of various classes was studied. The highest values of the static exchange capacity were observed in sorption from a LiHCO3 solution onto imino carboxylic ion exchangers Amberlite IRC 748 (Rohm and Haas, the United States), Purolite S930 (Purolite, the United Kingdom), and AXIONIT 3S (AO Aksion RDM, Russia). In sorption from a LiCl solution with рН 1.4, the sorption capacity of all the sorbents tested is 3–7 lower. Sorption treatment of a LiHCO3 solution to remove Na, K, Са, Mg, Al, Si, Ti, Cr, Mn, Fe, Ni, Cu, and Zn impurities under dynamic conditions using AXIONIT 3S imino carboxylic sorbent was performed. The sorption ensures deep removal of Ca, Cu, and Zn impurities from a LiHCO3 solution. A procedure was suggested for preparing high-purity lithium carbonate by ion-exchange purification of a LiHCO3 solution on an imino carboxylic sorbent, followed by thermal decomposition of the purified solution at the boiling point to obtain a lithium carbonate precipitate. Lithium carbonate with the main substance content of 99.90 ± 0.05 wt % was obtained.

Selective dissolution of rare-earth element carbonates in deep eutectic solvents

Dissolution in choline-chloride based deep eutectic solvents (DES) of rare earth elements (REE) from high-purity single carbonate salts of Y, La, Ce, Nd and Sm and from their multicomponent mixtures and also bastnäsite mineral was assessed with a prospect to gain an understanding on the leaching behavior of bastnäsite ores as REE source from DES suspensions. Urea, malonic acid and citric acid were used in different proportions with choline chloride in order to form deep eutectic solvents with desired viscosity and functionality. The results obtained prove promising for use insolvato-metallurgical processes in terms of selective dissolution of the higher-atomic-number (Z) rare earth elements at the expense of the lower-ZREEs and the gangue-originating metal impurities, thus initiating separation among the different REE members from the early hydrometallurgical steps.

Structural, dielectric, electrical and magnetic characteristics of lead-free multiferroic: Bi(Cd0.5Ti0.5)O3[sbnd]BiFeO3 solid solution

This communication provides the detailed description of the synthesis and characterization of a lead-free multiferroic solid solution of Bi(CdTi)O3 and BiFeO3 of a general chemical composition Bi(Cd0.45Ti0.45Fe0.10)O3 (abbreviated as BCTFO). The material has been synthesized via a solvent-free solid-state reaction approach by utilizing high-purity oxides and carbonate in appropriate stoichiometric amount. The structural, morphological, molecular structure, electrical and magnetic characteristics of as-synthesized electronic system were examined by the powder X-ray diffraction, field emission scanning electron microscopy, vibrating sample magnetometer and impedance spectroscopy techniques respectively in different experimental conditions. Analysis of X-ray diffraction data of BCTFO shows a single-phase formation of the material in orthorhombic crystal symmetry with very fine powder (average linear crystallite dimension = 30 nm). Detailed studies of dielectric parameters (dielectric constant, tangent loss and polarization) in a selected frequencies (1 kHz–1.5 MHz) and temperatures (300 K–773 K) clearly exhibit one of the important components of multiferroics (i.e., ferroelectricity). Studies of some components of electrical parameters (dielectric, impedance, electric modulus and conductivity) of complex spectroscopy confirmed the existence of non-Debye type and other type of dielectric relaxation process in the material. The correlation between the real and idealized circuit response at several temperatures has been investigated by using ZSIMP WIN software and impedance data. Study of another component of multiferroics (i.e., field dependent magnetization) of BCTFO shows the significantly higher value of remnant and spontaneous magnetization. Thus, the existence of dielectric polarization and magnetization is single phase (orthorhombic) in a distorted perovskite confirms the multiferroicity of bismuth ferrite modified bismuth cadmium titanate (BCTFO) at room temperature, and hence the material can be used for some multifunctional applications.

Leaching of Metal Ions from Blast Furnace Slag by Using Aqua Regia for CO2 Mineralization

Blast furnace slag (BFS) was selected as the source of Ca for CO2 mineralization purposes to store CO2 as CaCO3. BFS was dissolved using aqua regia (AR) for leaching metal ions for CO2 mineralization and rejecting metal ions that were not useful to obtain pure CaCO3 (as confirmed by XRD analysis). The AR concentration, as well as the weight of BFS in an AR solution, was varied. Increasing the AR concentration resulted in increased metal ion leaching efficiencies. An optimum concentration of 20% AR was required for completely leaching Ca and Mg for a chemical reaction with CO2 and for suppressing the leaching of impurities for the production of high-purity carbonate minerals. Increasing the liquid-to-solid ratio (L/S) resulted in the increased leaching of all metal ions. An optimum L/S of 0.3/0.03 (=10) was required for completely leaching alkaline-earth metal ions for CO2 mineralization and for retaining other metal ions in the filtered residue. Moreover, the filtrate obtained using 20% AR and an L/S of 0.3/0.03 was utilized as Ca sources for forming carbonate minerals by CO2 mineralization, affording CaCO3. The results obtained herein demonstrated the feasibility of the use of AR, as well as increasing pH, for the storage of CO2 as high-purity CaCO3.

Self-sustaining carbon capture and mineralization via electrolytic carbonation of coal fly ash

This study presents a new electrolytic carbonation process to synergize the treatment of different waste streams generated by power plants, including fly ash, brine wastewater, and CO2. The acidity generated by electrolysis of brine electrolyte directly liberates calcium from fly ash. The metal ions balance the OH− produced at the cathode to form hydroxide, which then fixes CO2 into high purity carbonate precipitates. Results show that electrolysis increased fly ash dissolution by 32.4% compared to the control with spontaneous dissolution of fly ash, and the carbonation process captured 89% more CO2 and increased capture capacity from 9.75 to 18.42kg-CO2/t-fly ash in the NaCl electrolyte. The energy expenditure was 19.4–29.3kJ/mol-CO2, lower than that required for sorbent or solvent based post-combustion carbon capture. The process takes advantage of all waste streams generated on site and can consolidate traditionally separated treatment processes to save costs, produce energy and value-added products, as well as generate carbon benefits.

Synthesis of high-purity precipitated calcium carbonate during the process of recovery of elemental sulphur from gypsum waste

We recently showed that the production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste by thermally reducing the waste into calcium sulphide (CaS) followed by its direct aqueous carbonation yielded low-grade carbonate products (i.e. <90mass% as CaCO3). In this study, we used the insight gained from our previous work and developed an indirect aqueous CaS carbonation process for the production of high-grade CaCO3 (i.e. >99mass% as CaCO3) or precipitated calcium carbonate (PCC). The process used an acid gas (H2S) to improve the aqueous dissolution of CaS, which is otherwise poorly soluble. The carbonate product was primarily calcite (99.5%) with traces of quartz (0.5%). Calcite was the only CaCO3 polymorph obtained; no vaterite or aragonite was detected. The product was made up of micron-size particles, which were further characterised by XRD, TGA, SEM, BET and true density. Results showed that about 0.37 ton of high-grade PCC can be produced from 1.0 ton of gypsum waste, and generates about 0.19 ton of residue, a reduction of 80% from original waste gypsum mass to mass of residue that needs to be discarded off. The use of gypsum waste as primary material in replacement of mined limestone for the production of PPC could alleviate waste disposal problems, along with converting significant volumes of waste materials into marketable commodities.

Factors affecting the precipitation of pure calcium carbonate during the direct aqueous carbonation of flue gas desulfurization gypsum

The mineral carbonation of FGD (flue gas desulfurization) gypsum was carried out through CO2 sorption into ammonia solution containing FGD gypsum. High-purity calcium carbonate was precipitated from DCC (dissolved calcium carbonate) solution which was extracted during the induction period. The factors affecting the preparation of pure calcium carbonate were examined under the following conditions: CO2 flow rate (1–3 L/min), ammonia content (4–12%), and S/L (solid-to-liquid) ratio (5–300 g/L). X-Ray diffraction study revealed that the PCC (precipitated calcium carbonate) was round-shaped vaterite. The induction time for PCC decreased as the CO2 flow rate increased. The maximum formation efficiency for pure PCC was seen to increase linearly with the ammonia content. The formation efficiency for pure PCC was the highest (90%) for S/L ratio of 5 g/L but it decreased as S/L ratio increased. On the other hand, S/L ratio didn't affect the maximum solubility limit of DCC. It is believed that the pure PCC would add an economic value to the FGD gypsum carbonation for industrial CO2 sequestration.

A Novel Method for CO2 Sequestration via Indirect Carbonation of Coal Fly Ash

Coal fly ash is a potential candidate for CO2 mineral sequestration. If calcium is extracted selectively from coal fly ash prior to carbonation (namely indirect carbonation), a high-purity and marketable precipitated calcium carbonate (PCC) can be obtained. In the extraction process, recyclable ammonium salt (i.e., NH4Cl/NH4NO3/CH3COONH4) solution was used as a calcium extraction agent in this study. The influence of time, temperature, agent concentration, and solid-to-liquid ratio on calcium extraction efficiency was explored. NH4Cl/NH4NO3/CH3COONH4 are confirmed to be effective calcium extraction agents for the high-calcium coal fly ash investigated, and about 35–40% of the calcium is extracted into the solution within an hour. The calcium extraction performance is best for CH4COONH4, followed by NH4NO3 and NH4Cl. Increasing temperature from 25 to 90 °C and agent concentration from 0.5 to 3 mol/L only subtly increases calcium extraction efficiency for NH4Cl and NH4NO3, while the positive effect of incre...

Bench-Scale Operation of a Concrete Sludge Recycling Plant

A bench-scale plant for waste concrete sludge recycling was designed, constructed, and operated. Real concrete sludge generated from a pile and pole production plant and groundwater were used for the experiments. The process mainly consists of the extraction of calcium ions from the concrete sludge into the aqueous phase and the crystallization of calcium carbonate from the solution with CO2. The CO2 was supplied from boilers installed in the plant, where heavy oil is combusted. High-purity calcium carbonate (>99%) was obtained in the process, with particle sizes distributed in the range of 3–30 μm (volume-based), peaking at about 10 μm. A net reduction in CO2 emissions can be achieved based on the process power consumption and the amount of product. The effects of operating conditions on process performance data such as calcium extraction rate and calcium carbonate crystallization rate were examined, which can lead to scaling-up of the plant.

Effect of Barium Aluminates on Acid Resistance of Fracturing Proppants

In order to explore the effect of removing siliceous components on acid resistance of fracturing proppants, acid resistance of fracturing proppants in a new silicon-free system was studied in this paper. The fracturing proppants were made by pressureless sintering using high-purity alumina and barium carbonate as the basic raw material. Acid resistance test was carried out in 12 wt% HCl + 3 wt% HF at 65 oC for 30 minutes according to The Petroleum and Gas Industrial Standards of China (SY/T5108-2006) and morphology, structure and chemical analysis of the samples were investigated using X-ray diffraction and scanning electron microscopy. Experiments show that fracturing proppants that contain barium aluminates have better acid resistance. The acid solubility of the samples is less than 3%, especially when the content of barium carbonate is about 10% (mass fraction, the same below), the acid solubility of the sample reaches 0.52% which is far beyond the demands (5%) of the Standards of SY/T5108-2006. Results prove that the removal of siliceous components of raw materials can prominently improve the acid resistance of fracturing proppants. It can provide a new referential thought for improving the acid resistance of fracturing proppants.

Investigation of Drying Conditions for High-Purity Sodium Carbonate

Sodium carbonate, a primary standard of volumetric analysis, is used as a standard of hydrochloric acid and sulfuric acid in Japan, and is certified in different countries by using different drying conditions. The drying conditions for reference materials have a significant effect on the titration results due to changes in the acidimetric factor. The drying conditions for sodium carbonate were investigated by thermogravimetry-mass spectrometry (TG-MS), gravimetric titration, mass and pH measurements. In TG-MS analysis, about 29 mg of sodium carbonate was heated from room temperature to 700°C. The loss through heat was 2.1%, and the amount of water content detected was 1.8%. Most of the weight lost through heat was caused by releasing water, which was produced at about 100°C, and carbon dioxide was released at about 100°C and 600°C. The weight of sodium carbonate dried at different temperatures was decreased, which also indicates the decomposition of sodium carbonate under high-temperature conditions. Sodium carbonate samples dried at 100°C to 700°C for 1 h were gravimetrically cross-titrated with each other using 1.5 mol/L hydrochloric acid as an intermediate titrant. The effective purity of sodium carbonate was significantly increased at over 400°C. In addition, the pH value of carbonate-free solutions of sodium carbonate dried at different temperatures prepared by precipitation as a barium carbonate was increased, especially at over 500°C. It was concluded that suitable drying conditions were 200°C∼400°C, and the optimum condition was approximately 300°C for 2 h.

Water-resistant lime-magnesian clinker

A technological scheme has been developed for producing water-resistant lime-magnesian clinker and powders based on high-purity dolomites, dolomitized magnesite, lime, chalk, calcium carbonate, and magnesium without additives impairing the physicochemical properties of refractory materials. The hydration resistance of clinkers and granular materials containing free CaO is determined by their high density, which is equal to 95–98% of the theoretical density. The properties of such clinkers and powders give reason to expect the production of functional lime-magnesian refractories whose properties in some cases are not inferior to periclase-based analogs.

An assessment of calibration strategies for the quantitative and semi-quantitative analysis of calcium carbonate matrices by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS)

Calibration procedures for the analysis of natural calcium carbonate-rich materials by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are herein evaluated. Calibration lines were constructed using: (a) commercially available glass reference materials; (b) high-purity calcium carbonate powder spiked with the analytes of interest, and (c) natural geological reference materials. The analytes initially considered were Ba, Cd, Fe, Mg, Mn, Pb, Sr, U and V, although some low concentrations, or lack of reference data, particularly for Cd and U, precluded a complete assessment. Calcium and indium were evaluated as internal standard candidates; data were subsequently corrected using calcium as this was the more reliable internal standard. The analysis of geological reference materials using glass calibration lines shows a systematic offset in measured versus reference, or accepted, values; future derivation of a `correction factor' may therefore be possible. The preferred calibration strategy, for the LA-ICP-MS analysis of calcium carbonate samples, uses selected natural geological reference materials.

Use of Soft Limestone for Road-Base Construction in Belize

The results of a highway experiment, constructed in May 1978 in northern Belize, designed to investigate the suitability of locally occurring calcareous materials, known as marls, for road bases are discussed. The marls comprise high-purity carbonate materials containing mainly siltsized particles and fall outside the grading, plasticity, and strength specifications normally required for road bases. Three marls, each with slightly different characteristics, were substituted as road base for crushed stone. One of the marls was also stabilized with ordinary portland cement. Detailed monitoring was then undertaken periodically to determine their performance. The road pavement was constructed on an embankment to ensure good drainage. A good quality surface dressing seal has been maintained. After 19 years of traffic, measured at 1.3 million equivalent standard axles, the marl road bases have performed at least as well as the crushed stone. The cement-stabilized marl road base performed exceptionally well. Stabilization would enable the use of more plastic marls.

Determination of lead concentration and lead isotope ratios in calcium supplements by inductively coupled plasma mass spectrometry after high pressure, high temperature digestion

The presence of lead as a contaminant in calcium supplements has aroused considerable public health interest in recent years. In this investigation lead and lead isotope ratios were determined by ICP-MS in ten brands of calcium supplements after high pressure/temperature digestion. Calcium supplements (200 to 250 mg) were digested in 2 mL of nitric acid at 230 °C and at a pressure of 1770 psi (1.2 × 104 kPa). Lead concentrations were determined by matrix-matched lead standards prepared in a high-purity calcium carbonate matrix. Good recoveries of lead and calcium were obtained for certified animal bone reference material. High levels of Pb (8 to 28 μg Pb per g of calcium) were found in calcium supplements that contain dolomite or bone meal. Chelated and refined calcium supplements had lower Pb levels (0.8 to 0.9 μg Pb/g Ca). Application of lead isotope ratios to distinguish the origin of calcium sources was also explored.