A new method for the treatment of chromite ore processing residues ...
Oct 22, 2007 ... Chromite ore processing residue (COPR), derived from the so-called high-lime processing of chromite ore, contains a significant fraction of a leachable Cr(VI) which is harmful to human being and other organisms. In recent years, the concern over environmental pollution from the waste residue containing...Read More
Evaluation of the treatment of chromite ore processing residue by ...
Jul 15, 2009 ... The effectiveness of the treatment of chromite ore processing residue (COPR) with ferrous sulfate and encapsulation into asphalt were explored separately and in combination. The asphalt treatment was conducted by mixing COPR or ferrous sulfate pretreated COPR with varying amounts of asphalt.Read More
Pyrolysis Treatment of Chromite Ore Processing Residue by ...
Feb 10, 2016 ... The pyrolysis treatment with biomass is a promising technology for the remediation of chromite-ore-processing residue (COPR). However, the mechanism of this process is still unclear. In this study, the behavior of pyrolysis reduction of Cr(VI) by cellulose, the main component of biomass, was elucidated.Read More
Treatment of Hexavalent Chromium in Chromite Ore Processing ...
Jul 15, 2005 ... We investigated a method for delivering ferrous iron into the subsurface to enhance chemical reduction of Cr(VI) in chromite ore processing solid waste (COPSW) derived from the production of ferrochrome alloy. The COPSW is characterized by high pH (8.5−11.5) and high Cr(VI) concentrations in the solid...Read More
Treatment of hexavalent chromium in chromite ore processing solid ...
Environ Sci Technol. 2005 Aug 15;39(16):6208-16. Treatment of hexavalent chromium in chromite ore processing solid waste using a mixed reductant solution of ferrous sulfate and sodium dithionite. Su C(1), Ludwig RD. Author information: (1)Ground Water and Ecosystems Restoration Division, National Risk Management...Read More
Importance of Mineralogy in the Geoenvironmental ... - ASCE Library
Importance of Mineralogy in the Geoenvironmental Characterization and Treatment of Chromite Ore Processing Residue ... and Maryland) included geotechnical, chemical, mineralogical, and leaching analyses of three main chromite ore processing residue (COPR) types [gray-black (GB), hard brown (HB), clayey (C)].Read More
Importance of Mineralogy in the Geoenvironmental ... - ASCE Library
The geoenvironmental characterization of COPR at two deposition sites (New Jersey and Maryland) included geotechnical, chemical, mineralogical, and leaching analyses of three main chromite ore processing residue (COPR) types [gray-black (GB), hard brown (HB), clayey (C)]. Quantitative mineralogical analyses were...Read More
Evaluation of the treatment of chromite ore ... - Europe PMC
The effectiveness of the treatment of chromite ore processing residue (COPR) with ferrous sulfate and encapsulation into asphalt were explored separately and in combination. The asphalt treatment was conducted by mixing COPR or ferrous sulfate pretreated COPR with varying amounts of asphalt. To assess the efficacy of...Read More
Advances towards a Clean Hydrometallurgical Process for Chromite
Jan 28, 2016 ... Therefore, the development of a clean treatment process for chromite has become a significant concern. 2. Chromium Salt Preparation Technology. Chromium-bearing ores are found in many forms, but the economically extractable form is mineral chromite, which is inert and insoluble in water in its spinel...Read More
Chromium steel from chromite ore processing residue — A valuable ...
The primary objective of this study is to demonstrate an efficient and optimum way to recover chromium and iron from chromite ore processing residues (COPR) for the production of chrome steel and stainless steel. In Hudson ... chromite ore processing residue chromium steel reduction thermal treatment beneficial use.Read More
Enhancing the Utilization Potential of a Low Grade Chromite Ore ...
Beneficiation of the ore was undertaken using gravity based methods. Inadequate liberation prevented any significant enrichment at 0.9 mm top size. At 0.3 mm top size, the spiral concentration generated a concentrate with 40.5% Cr2O3 from the coarser fraction. The finer fraction was treated in a shaking table to generate...Read More
Environmental Scenario of Chromite Mining at Sukinda Valley – A ...
International Journal of Environmental Engineering and Management ... Odisha is endowed with vast mineral deposits like coal, chromite, iron ore, manganese ore, bauxite etc.India is the second largest producer of chromites in the world and 98% of total chromite reserves of the country are available in Odisha. Chromite is...Read More
Conversion of Chromium Ore Processing Residue to Chrome Steel
weathered and mixed COPR, commonly referred to as chromium contaminated soils, in Hudson. County, NJ. Several technologies were developed for treating of chromium contaminated media including, but not limited to, stabilization, vitrification, electro-kinetic treatments, separation, soil washing, and bioremediation.Read More
Threshold value of Chromite Ore. - Indian Bureau of Mines
Aug 23, 2017 ... RESEARCH & DEVELOPMENT ON BENEFICIATION BY IBM. Study 3: Upgradation of Low Grade Dumped Chrome Ore. Chrome ore assaying 35 to 40% Cr2O3 are treated in the chrome ore beneficiation plant of. M/s OMC to produce chromite concentrates assaying around 48-50% Cr2O3. Ores assaying.Read More
CPY Document - IARC Monographs
CHROMIUM AND CHROMIUM COMPOUNDS. 69. Ferrochromium Is produced by treatment of chromite ore in electric furnaces using coke as a reducing agent. Worldwide production figures for all grades of fer- rochromium are summarized in Table 8. Tabié 8. World production offerrochromium (ail grades, in thousands.Read More
Chromium processing | Britannica.com
In 1893 Henri Moissan smelted chromium ore and carbon in an electric furnace and produced ferrochromium; this has remained the basis of the modern .... The low-carbon ferritic stainless steels cannot be hardened by heat treatment; ferritic varieties containing 17 to 18 percent chromium are used in automobile trim and in...Read More
Treatment of Alkaline Cr(VI)-Contaminated Leachate with an ...
A well-publicized case of this occurred in Glasgow, United Kingdom, where poorly controlled disposal of a cementitious industrial by-product, chromite ore processing residue (COPR), has resulted in extensive contamination by Cr(VI)-contaminated alkaline leachates. In the search for viable bioremediation treatments for...Read More
Calcium polysulfide treatment of Cr(VI)-contaminated soil
Mar 19, 2010 ... ical parameters in bench scale studies. The only peer-reviewed literature identified was on the use of CPS to treat chromite ore processing residue (COPR) [10–12]. X-ray absorption near edge structure (XANES) analyses in COPR studies showed that while dis- solved Cr(VI) was successfully treated, solid...Read More
Chromium in South Africa - SAIMM
Feb 2, 1986 ... SYNOPSIS. The locations of potential reserves of chromite ores throughout the world are discussed. Reference is made to the marked changes in international trade in chromite ores during the past ten to fifteen years, and to the change in locality of ...... ore treated by the various beneficiation processes. 42.Read More
from chromite ore processing residue through acid treatment
Chromite ore. Processing residue. Chromium. Acid treatment. Leaching. 1. Introduction. Historical processing of chromite ore involved mixing dry- milled ore with lime (CaO) and soda ash (Na2CO3), followed by roasting at high temperatures to promote oxidation of the trivalent chromium, Cr(III), within the ore. Hexavalent...Read More
Chromium (Cr) - Chemical properties, Health and Environmental ...
chemical properties, health and environmental effects of chromium. ... Chromium ores are mined today in South Africa, Zimbabwe, Finland, India, Kazakihstan and the Philippines. A total of 14 million tonnes of chromite ore is ... Respiratory symptoms may include coughing and wheezing, shortness of breath, and nasal itch.Read More
Treatment of Platinum Flotation Products
recover pgms and non-ferrous metals from low- sulfide pgm-bearing ores has considerably simplified the treatment, decreased the operating costs and improved the environmental conditions. Our investigations involved flotation concen- trates of low-sulfide platinum-bearing chrome ores from South Africa. The ore had the...Read More
Calcium polysulfide remediation of hexavalent chromium ...
Dec 20, 2017 ... Past disposal of high-lime chromite ore processing residue (COPR) from a chemical works in S.E. Glasgow, UK, has led to continuing release of toxic and ... which have demonstrated the effectiveness of the treatment in quantitatively and rapidly reducing Cr(VI) to Cr(III) over the pH range (8-12.5) typically...Read More
Optimal design of a secondary milling circuit for treating chromite ...
... were carried out to investigate the optimal design of a secondary milling circuit configuration. The optimal design consisted of a conventional hydrocyclone to de-slime the feed, followed by gravity separation with a spiral concentrator circuit to separate the ore into lights (silicates-rich) and heavies (chromite-rich) fractions.Read More
chrome ore washing plant screening plant
We can supply the whole line of Chrome ore washing plant, including: 1. trommel screen / vibrating screen ...Chrome Ore Washing Plant,Screening ... chrome ore washing effluent treatment plant Overview. thunderbird wash plants used Xinhai Mining. ... chrome ore washing plant screening plant chromite ore ... Chat Online...Read More
Chromium stability of treated chromite ore processing residue by co ...
Co-pyrolysis process with biomass is a new kind of method for the treatment of chromite ore processing residue(COPR),through which Cr(Ⅵ) can effectively be converted into Cr(Ⅲ).However,due to the high chromium content in the treated product,its chromium stability should be studied.In this study,the chromium safety in...Read More
Transport of hexavalent chromium in the vadose zone by capillary ...
Oct 13, 2015 ... Importance of mineralogy in the geoenvironmental characterization and treatment of Chromite Ore Processing Residue. Journal of Geotechnical and Geoenvironmental Engineering 136(3): 510-521 Crossref. Di Palma, LD, Gueye MT, Petrucci E. 2015. Hexavalent chromium reduction in contaminated soil: a...Read More
Chromium - Wikipedia
Sodium chromate is produced industrially by the oxidative roasting of chromite ore with calcium or sodium carbonate. The dominant species is therefore, by the law of mass action, determined by the pH of the solution. The change in equilibrium is visible by a change from yellow (chromate) to orange (dichromate), such as...Read More
factors affecting the reducibility of sintered chromite ... - Pyro.co.za
Sintered pellets have shown a superiority over lumpy ore and briquettes made of the same chromite grade. The good ... mium depends on the grade of chromite, the method of chromite pre-treatment and the smelting process (e.g. ... grinding) and oxidation degree (weathered ore) of chromite raw materials on reducibility. 2.Read More
Potential Toxic Effects of Chromium, Chromite Mining and ...
Chromium-III oxidation to Cr-VI occurs under favourable. pH and moisture conditions with the presence of manganese oxides, alkali oxides or calcium compounds, during bush fires, water treatment, waste incineration and chromite ore dry grinding and smelting. Chromium-VI can have long residence times in surface water,...Read More
Maria Chrysochoou - Google Scholar Citations
Ettringite-induced heave in chromite ore processing residue (COPR) upon ferrous sulfate treatment. D Dermatas, M Chrysochoou, DH Moon, DG Grubb, M Wazne, ... Environmental science & technology 40 (18), 5786-5792, 2006. 88, 2006. A comparative evaluation of hexavalent chromium treatment in contaminated soil by...Read More
Hexavalent Chromium Reduction in Solution and in Chromite Ore ...
Apr 5, 2013 ... Chromite ore processing residue (COPR), the solid waste product from the high-temperature alkaline processing of ferrochromite (FeO·Cr2O3), ... The combined treatment of tartaric acid, IPOH, Mn2+, and a strong acid to lower the pH of COPR-enriched soils would be effective in field applications of this...Read More
Comparative study of alkali roasting and leaching of chromite ores ...
Aug 13, 2015 ... temperatures has been investigated for the treatment of titanium oxide minerals and chromium ores. The present work is focussed on studying the physico-chemical changes that occur during the alkali roasting of ilmenite mineral concentrates and chromite ores, using sodi- um and potassium hydroxides.Read More
Chromite Mining - Lakehead University Faculty Sites
Chromite Market Demand. 4. Exploration in Ontario. 5. Cliffs Natural Resources Inc. 7. MINING PROCESS. 8. Cliffs Proposal – Ore Extraction. 8. Cliffs Proposal – Ore Processing. 10. Cliffs Proposal – Waste Management. 10. ENVIRONMENTAL IMPACTS. Scope. 11. Acid Mine Drainage. 12. Heavy Metal Contamination. 13.Read More
Remediation of chromite ore processing residue using solidification ...
Sep 18, 2014 ... Disposal of Chromite Ore Processing Residue (COPR) is a major concern from an environmental point of view because it consists mainly of Cr(VI) in addition to Cr(III). Cr(VI) is more soluble and mobile when compared to Cr(III). The study primarily concentrated on treatment of COPR using solidification and...Read More
Treatment of Cr(VI)
Introduction. South Africa holds approximately three- quarters of the world's viable chromite ore resources1,2,3 and dominates the global production of ferrochrome(FeCr)4. FeCr is a relatively crude alloy of predominantly iron and chromium, used mainly in the production of stainless steel. There are currently fourteen.Read More
Toxicological Profile for Chromium
CHROMIUM. 351. 5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL. 5.1 PRODUCTION. Tables 5-1 and 5-2 list the facilities in each state that manufacture ... Chromite ore and foundry sand; chromium chemicals, ferroalloys, and metal; and stainless steel represent ..... disposed of in landfills after proper treatment.Read More
Independent Technical Experts Report on the ... - Sylvania Platinum
Feb 27, 2011 ... Samancor Chrome to treat its current tailings risings and its existing tailings dams using the Sylvania ... direct current (DC) furnace technology to treat high chrome low grade PGE concentrates ... The information in this report (and the appendices) relating to exploration results, mineral resources and ore.Read More
CLU-IN | Contaminants > Chromium VI > Treatment Technologies
Jan 22, 2018 ... Following earlier field trials that indicated the effectiveness of calcium polysulfide (CaSx) application in reducing Cr(VI) associated with chromite ore processing residue, another field trial was conducted in 2009 to identify the most effective CaSx delivery mechanism into the subsurface. The methods...Read More
Evaluation of ettringite-related swelling mechanisms for treated ...
Sep 17, 2014 ... Abstract Accelerated one-dimensional unconfined swell tests were conducted for ferrous sulfate chromite ore process- ing residue (COPR) field-treated samples. The field-treated samples were subjected to wet and dry cycles over 100 days to accelerate the lithification of the samples. Parallel laboratory.Read More