The present disclosure generally relates to processes for the reduction of transition metals using alkali metals to produce reduced transition metals.

The present disclosure generally relates to processes for the reduction of transition metals using alkali metals to produce reduced transition metals.

A method and system for recovering a high yield of low carbon ferrochrome from chromite and low carbon ferrochrome produced by the method. A stoichiometric mixture of feed materials including scrap aluminum granules, lime, silica sand, and chromite ore are provided into a plasma arc furnace. The scrap aluminum granules are produced from used aluminum beverage containers. The feed materials are heated, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxide in the chromite to produce molten low carbon ferrochrome with molten slag floating thereon. The molten low carbon ferrochrome is extracted, solidified and granulated into granules of low carbon ferrochrome. The molten slag is extracted, solidified and granulated into granules of slag.

The present invention discloses a treatment method for resource recycling of hexavalent chromium-containing residues, belonging to a field of a clean treatment and resource recycling of chromium-containing residues. This method comprises steps as follows: 1) adding water to the hexavalent chromium-containing residues and mixing uniformly; 2) adding mineralizers to a solution obtained in step 1) and stirring sufficiently to obtain a mixed liquid; and the mineralizers are sodium chlorate, sodium perchlorate and hydrochloric acid; 3) treating the mixed liquid by a hydrothermal method or direct heating; 4) after the heating treatment, naturally cooling a solid-liquid mixture to room temperature for holding; 5) separating solid residues and a chromium-containing supernatant, and washing filtered residues with water and then drying; and 6) recycling a chromium-containing solution for returning to a work section, or for a treatment of recycling chromium. This method may achieve full-residue utilization with simple process, low cost, quick effect, large treating capacity and complete detoxification, and has relatively high social benefit and economic benefit.

The present invention discloses a treatment method for resource recycling of hexavalent chromium-containing residues, belonging to a field of a clean treatment and resource recycling of chromium-containing residues. This method comprises steps as follows: 1) adding water to the hexavalent chromium-containing residues and mixing uniformly; 2) adding mineralizers to a solution obtained in step 1) and stirring sufficiently to obtain a mixed liquid; and the mineralizers are sodium chlorate, sodium perchlorate and hydrochloric acid; 3) treating the mixed liquid by a hydrothermal method or direct heating; 4) after the heating treatment, naturally cooling a solid-liquid mixture to room temperature for holding; 5) separating solid residues and a chromium-containing supernatant, and washing filtered residues with water and then drying; and 6) recycling a chromium-containing solution for returning to a work section, or for a treatment of recycling chromium. This method may achieve full-residue utilization with simple process, low cost, quick effect, large treating capacity and complete detoxification, and has relatively high social benefit and economic benefit.

A method for processing fines bearing iron or other metals, such as manganese, bauxite, boron, chromium, iron-nickel and/or ferrous slags, from various possible sources, possibly with the addition of self-reducing agents and other minerals for chemical adjustment, with particle size up to 6.3 mm (through ? inch sieve), directly into the intense mixer, with a set of binders in specific proportions, aiming to optimize physical and metallurgical properties of the briquettes with minimal binder addition, thus not compromising the quality of steel or other metal products. The binders are starch, sodium silicate and a base such as sodium hydroxide. The mixture with adjusted moisture content goes through a conventional briquetting roller press. The green briquettes then undergo drying with forced air at around 150? C. for a short time, or at ambient temperature for a longer time. The briquettes obtained have excellent metallurgical properties, and sufficient physical resistance for handling and transport, without the high and undesirable economic and environmental costs of the hot briquetting process.

A method of chromite reduction using cryolite (Na.sub.3AlF.sub.6) as an additive. The cryolite used may be pure cryolite or an impure mixture containing cryolite, such as the bath material produced as waste or as a by-product of aluminum smelting processes. In one embodiment, the reduction product is re-melted at a higher temperature to form larger metallic particles. In another embodiment, the chromite ore is granulated with cryolite particles and carbon reductant particles before being reduced.

A method of chromite reduction using cryolite (Na.sub.3AlF.sub.6) as an additive. The cryolite used may be pure cryolite or an impure mixture containing cryolite, such as the bath material produced as waste or as a by-product of aluminum smelting processes. In one embodiment, the reduction product is re-melted at a higher temperature to form larger metallic particles. In another embodiment, the chromite ore is granulated with cryolite particles and carbon reductant particles before being reduced.

This invention relates to a method for controlling exothermic reactions between metal chlorides of Zn, V, Cr, Co, Sn, Ag, Ta, Ni, Fe, Nb Cu, Pt, W, Pd, and Mo, and Al and the use of the method for preparation of metallic alloys and compounds based on base metals Zn, V, Cr, Co, Sn, Ag, Ta, Ni, Fe, Nb Cu, Pt, W, Pd, and Mo. The method provides for a mixture of precursor chemicals including at least one solid base metal chloride to be mixed and reacted exothermically with a control powder based on Zn, V, Cr, Co, Sn, Ag, Ta, Ni, Fe, Nb Cu, Pt, W, Pd, and Mo and then reacting the resulting intermediates with an Al scavenger. Reduction is carried out in a controlled manner to regulate reaction rates and prevent excessive rise in the temperature of the reactants and the reaction products.

The present invention discloses a detoxification treatment method for extracting and recycling chromium from hexavalent chromium-containing residues, comprising steps as follows: 1) adding water to the hexavalent chromium-containing residues and mixing uniformly; 2) adding sodium sulfate, sodium chlorate and sulfuric acid to a solution obtained in step 1) and stirring, sufficiently to obtain a mixed liquid; 3) treating the mixed liquid by a hydrothermal method or direct heating; 4) after the heating treatment, naturally cooling a solid-liquid mixture to room temperature for holding; 5) separating solid residues and a chromium-containing supernatant, and washing filtered residues with water and then drying; 6) precipitating the supernatant and the water used for washing the filtered residues with a precipitant CaCl.sub.2, then centrifugally washing, dewatering and drying the precipitates; and 7) recycling a chromium-containing solution for returning to a work section, or for a treatment of recycling chromium. This method may achieve full-residue utilization with simple process, low cost, quick effect, large treating capacity and complete detoxification.