Recovery of chromium by calcium-roasting, sodium-roasting, …
chromium leaching out, which including calcium-roasting, sodium-roasting, acid leaching, alkaline leaching and sub-molten technology. All the mentioned technologies in this paper are shown in Table 1. Chromite resources Chromium is an important national strategic source widely used in many eld, and it accounts 24th in the group VIB in
Preparation of Potassium Dichromate Crystals from the Chromite …
In the present investigation, the oxidizing roasting process of chromite with sodium carbonate to prepare potassium dichromate crystals was studied in the microwave field with air, by heating the chromite and sodium carbonate. The chromite and sodium carbonate heated separately at 1000 °C in the microwave oven (frequency: 2.45 GHz; …
Enhancement of nickel laterite ore bioleaching by
Higher Ni extraction rates were described for pre-treated Indian chromite (FeCr 2 O 4) Ni-laterite bioleaching using ... it appears to be a viable alternative to using a strong acid in the process. Chemical leaching using citric, oxalic, and acetic acids, and a mixture of these acids, was used to evaluate the Ni recovery from a Ni-laterite ore ...
Mineral processing: leaching process of chromium and
In this study, four Saudi Arabian chromite ore samples collected from Wadi Al Hawanet (samples I–III) and Jabal Al Wasq (sample IV) areas were digested in the …
Quantitative mineralogical characterization of chrome ore
The production of chromite ores from the Sukinda valley comprises of predominantly powdery and friable ore types, and during mining, considerable quantities of low-grade ores (Cr2O3: <40wt%) are also handled. The low-grade ores are beneficiated in chrome ore beneficiation plants in order to obtain high-grade concentrates (Cr2O3: >45wt%). During
A Cr6+-Free Extraction of Chromium Oxide from Chromite Ores …
Oxidative alkali roasting of chromite is the state-of-the-art process for manufacturing chromium-containing chemicals, which involves dealing with serious environmental problems arising from handling Cr 6+-containing wastes generated in this process.In this article a new method for the extraction of Cr 2 O 3 from chromite ores is …
A clean and efficient leaching process for chromite ore
Developing a clean and efficient method to process chromite ore. The challenge of the liquid-phase oxidation process is to decompose chromite ore with milder reaction conditions including KOH concentration, temperature and oxygen partial …
Extraction of Cr (VI) from chromite ore processing residue
The effective extracting Cr(VI) from chromite ore processing residue (COPR) is the key to achieve COPR detoxification and recovery. We developed an effective method to extract Cr(VI) from COPR via controlling the phase transformation of Cr(VI)-containing minerals. Characteristic analysis showed that Cr(VI) was mainly incorporated in the …
(PDF) Sulfuric acid leaching of Turkish chromite …
The optimum process conditions of leaching treatment were found to be a temperature of 176 °C, a dichromic acid/chromite mass ratio of 0.12, and a sulfuric acid concentration of 81%.
Processes | Free Full-Text | Recycling of Chrome …
The treatment process flow included the operations of preliminary activation of the tailings in soda ash solution with a concentration of 120 g/dm 3 at 120 °C, S:L = 1:10 and a duration of 90 min, sulfuric …
Effect of Ball Mill Parameters' Variation on the Particles of a
A shrinking-core model was used to control the leaching process via surface chemical reaction. Y. Zhang et al. (Zhang and S. li ZHENG et al., 2010) carried out an experimental study on the MA effect on the alkali leaching of chromite ore. Their study shows that 97% recovery ratio was achieved when the chromium ore was mechanically …
Metals | Free Full-Text | Mechanism of Nickel, Magnesium, and
A new mechanism model for metal extraction from olivine-bearing ore by avoiding silica gel formation during leaching with hydrochloric acid including a carbonation pre-treatment is proposed. This study explains additionally a behavior of metals such as nickel, magnesium, and iron during a carbonation of olivine bearing ore and leaching of a ...
Leaching kinetics of acid-soluble Cr(VI) from chromite ore …
Key words: leaching; kinetics; hydrofluoric acid; hexavalent chromium; chromite ore processing residue 1 Introduction Chromite ore processing residue (COPR) is a solid residue produced by the so-called high lime process. COPR was classified as a hazardous waste for containing 1%−2% hexavalent chromium (Cr(VI)) [1], which is a mutagenic ...
Sulfuric acid leaching of South African chromite. Part 2: …
The alkaline roasting-water leaching process is featured by a high recovery of chromium from SSS slag, however, consumption of an amount of alkali reagent at high roasting temperature is the main drawbacks of this process. Both acidic and alkaline leaching processes have been reported to treat chromite ore as well as second …
Open Access proceedings Journal of Physics: Conference …
3.2 Separation and Purification of Nickel/Cobalt from Pregnant Leach Solution PTHPL will process nickel ore by HPAL technology under the temperature of 240℃~270℃ and Pressure of 3,400kPa~5,600kPa. The composition of raw material ore composition including limonite and saprolite from HPL mine is presented in Table 2 and Table 3.
Leaching of Valuable Elements from the Waste Chromite Ore …
The optimum parameters for COPR leaching were as follows: mechanical ball-milling time of 120 min, sulfuric acid concentration (w/w % H 2 SO 4) of 60%, …
A green method to leach vanadium and chromium from residue
Hydrogen peroxide as an oxidant was applied in leaching of vanadium and chromium in concentrated NaOH solution. Under the optimal reaction conditions (the liquid to solid ratio of 4.0 ml/g ...
Recovery of chromium by calcium-roasting, sodium-roasting
Jiao et. al. investigated the leaching behavior of chromium and magnesium from spent magnesia-chromium refractories by acid leaching combined with alkaline …
A New Method (Ball Milling and Sodium Sulfide) for
1. Introduction. The soda ash roasting process produces Chromite Ore Processing Residue (COPR) containing 1130–8500 mg/kg carcinogenic hexavalent chromium (Cr(VI)) due to the industrial incomplete leaching (Du and Chrysochoou, 2018, Chrysochoou et al., 2009)pared with the lime-based roasting process, soda ash as …
Decomposition mechanism of chromite in sulfuric acid–dichromic …
The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the …
Co-treatment of chromite ore processing residue and pyrolusite …
The production of chromate from the roasted chromite produces millions tons of Chromite Ore Processing Residue (COPR) annually [1], [14]. Due to the industrial incomplete roasting and leaching, about 6 wt% of Cr remain within COPR particles including 1130 − 8500 mg/kg of hazardous Cr(VI) [7].
Comprehensive Recovery of Valuable Metals From Spent
Zhao Q, Liu C, Shi P et al (2014) Sulfuric acid leaching of South African chromite. Part 1: study on leaching behavior. Int J Miner Process 130:95–101. Article CAS Google Scholar Chen G, Wang J, Wang X et al (2013) An investigation on the kinetics of chromium dissolution from Philippine chromite ore at high oxygen pressure in KOH sub …
Recovery of chromium and magnesium from spent magnesia …
Recovery of chromium and magnesium from spent magnesia-chrome refractories by acid leaching combined with alkali precipitation and evaporation ... It is predicted that the supply and demand gap of China's chromite ore will reach 4.3 million tons by 2020 [5]. ... A clean and efficient leaching process for chromite ore. Minerals …
Experimental Study on Sulfuric Acid Leaching Behavior of Chromite …
Utilizing Pakistan chromite as raw material, the rapid leaching of chromium and iron could be realized by the sulfuric acid leaching process on the condition of atmospheric pressure and the addition of oxidant A. And the leaching rate of chromium and iron would be 98.5% and 71.9%, respectively. The sulfuric acid leaching processes with …
Chemistry and Leaching Behavior of Chromite Ore Processing …
This study presents chemical, mineralogical, and leaching characterization of chromite ore processing residue (COPR) derived from the soda ash process, which is …
Effective separation and recovery of iron and chromium from …
In nitric acid pressure leaching (NAPL) for the treatment of limonitic laterite ores, the comprehensive utilization of leach residue is significant for resource recovery and environmental protection.In this work, the recovery and separation of iron and chromium from NAPL residue by metallization reduction roasting−magnetic separation with calcium …
Minerals | Free Full-Text | An Overview of Currently Applied
The majority of South African semi-closed SAFs operate on an acid slag regime (BF < 1). ... Bulut et al. (2009) found that Cr(VI) is fully solubilized after 30 min of leaching regardless of the solution pH ... İ. An efficient process for the beneficiation of a low grade chromite ore. Miner. Process. Extr. Metall. 2010, 119, 142–146. [Google ...
Cleaner Production of Chromium Oxide from Low …
Based on the findings of the work, a novel process for treating low-Fe (II) chromite by sulfuric acid-based leaching is proposed, and a chromium oxide is obtained as a product. No Cr-bearing wastes …
Technospheric mining of scandium from
Specifically, the used nickel laterite residue was a combination of the residues obtained from the acid leaching process and from the partial neutralisation process to remove the iron from the pregnant leach solution. The residue sample was washed, filtered, dried and homogenised at the sample location and was received as …
Microbial Leaching for Recovery of Nickel and Cobalt from Lateritic Ore
Two most common hydrometallurgical processes are high pressure acid leaching (HPAL) and reduction roast-ammoniacal leach (Caron process). ... (nearly 8–10 times that of the ore) that is generated during chromite mining and dumped nearby has found a very little use so far. The mineralogical studies indicated that there was no …