In the past decades the increased use of chromium (Cr) in several anthropogenic activities and consequent contamination of soil and water have become an increasing concern. Cr exists in several oxidation states but the most stable and common forms are Cr(0), Cr(III) and Cr(VI) species. Cr toxicity in plants depends on its valence state. Cr(VI) as being highly mobile is toxic, while Cr(III) as ...
The highest Cr extraction obtained was %. Further test work entailed exploring the effect of solid to liquid ratio using optimized conditions. The results showed a substantial increase of Cr extraction of up to 37%. This represents % decrease in chrome content, from % to %, in UG2 concentrate.
Extraction of Chromium (VI) From Mineral Acid Solutions by ... Email SMS Alerts. Email/SMS alert system is one of the key features and gives update information about the submitted manuscript. Read more... Read more. chrome extraction from ore. Chrome ore Extraction and refining is used in ore extraction process ... This was the earliest method used to extract the mineral from the ore ...
A process for the production of chromium nuggets from chromite ore/concentrate comprises: oxidizing chromite ore/chromium concentrate (1 ) comprising a Cr : Feratio ranging from to in a furnace (2) at a temperature of 900 °C, mixing (7) the oxidized ore (4) with reductant coal (5) and fluxes (lime, silica) (6), pelletizing (8) the mixture, reducing the pellets in a rotary ...
04/08/2021 · The highest Cr extraction obtained was %. Further test work entailed exploring the effect of solid to liquid ratio using optimized conditions. The results showed a substantial increase of Cr extraction of up to 37%. This represents % decrease in chrome content, from % to %, in UG2 .
By exposing chromite ore to aboveground conditions that promote weathering and oxidation, CrIII may be converted to mobile CrVI. Dry milling (grinding) of chromite ore is now known to convert CrIII to CrVI and efforts are required to avoid producing and spreading hexavalent chromium during mining activity.
which chromite penalties are applied will be equal to the TC of treating a chromitecontaining concentrate blended with sufficient mass of zerograde concentrate to reduce the grade of overall chromite values to below penalty levels. It has been reported that concentrates with chromite content of above per cent result in
A process for the production of chromium nuggets from chromite ore/concentrate comprises: oxidizing chromite ore/chromium concentrate (1 ) comprising a Cr : Feratio ranging from to in a furnace (2) at a temperature of 900 °C, mixing (7) the oxidized ore (4) with reductant coal (5) and fluxes (lime, silica) (6), pelletizing (8) the mixture, reducing the pellets in a rotary ...
of chromite due to metasomatism occurs for ores containing about 34% chromite, the amount of Cr 2 O 3 redistributed within the gangue can be even higher than at Vavdos, especially in low grade disseminated ores, where probably about 56% of Cr 2 O 3 can be hosted in the gangue, a value that could rise to 78 wt% for high Cr 2 O 3 Crchlorite ...
A method of obtaining chromite concentrate, comprising: a mechanical ore processing with the subsequent processing of concentrate sulfuric acid; after filtration of the solid residue, containing, wt.%: SiO 2 2,32 and Cr 2 About 3 56,85, subject classifiion and washed in countercurrent or vibrating column and the processing is primarily sodium hydroxide solution.
Chromium pollution due to leaching and weathering of chromite mine overburden in mine seepage water is a serious environmental problem. In an attempt to explore the indigenous chromate resistant and reducing bacteria from chromite mine quarry seepage, 145 aerobic, heterotrophic bacteria were isolated from 14 mine seepage samples derived from chromite mines of Sukinda valley and BaulaNuasahi ...
for converting Cr(VI) to Cr(lll). In essence ... peroxide (H20 2) and concentrated HN03 to extract the residual fraction. The selective extractions were ... RECOVERY OF Cr FROM CHROMITE ORE PROCESSING RESIDUES 2449 I :20 (COPR:H20 2)) at 60°C for 30 min.
Flotation of chromite and serpentine ScienceDirect . Jun 15 2007 · The contact and mixing time with the surfactant was kept constant at 600 s as found appropriate plus a contact of another 600 s when a modifier was also added while the flotation time was 120 s The obtained results in the concentrate were expressed as flotation recovery R in the normal manner 3 Results and discussion 3 1
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 () and high Cr(VI) concentrations in the solid phase (up to 550 mg kg(1)) and dissolved phase (357 mg L(1)). The dominant solidphase ...
Abstract Elevated concentration of hexavalent chromium pollution and contamination has contributed a major health hazard affecting more than 2 lakh mine workers and inhabitants residing in the Sukinda chromite mine of Odisha India Despite people suffering from several forms of ill health physical and mental deformities. More Detail.
· The soils, termed Low Hex and High Hex, contained 105 and 460 mg Cr(VI) kg −1, and g total Cr kg −1, and had pH values of and, respectively. Total cumulative Cr(VI) removed by the extractions was 49 and 386 mg kg −1 by both the batch equilibrations and leaching methods in the Low and High Hex soils, respectively, and no differences were found among the extractants.
