Method for preparing chromate by alkaline roasting carbon ferrochrome

A carbon ferrochromium and chromate technology, applied in chromate/dichromate and other directions, can solve problems such as chromate pollution, achieve reduced slag emissions, low acid-soluble chromate content, and reduced slag emissions. The effect of less slag

Inactive Publication Date: 2011-05-04
HUNAN JOYFLY TECH DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is: to solve the problems existing in the above-mentioned prior art, and to provide a me...

Method used

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  • Method for preparing chromate by alkaline roasting carbon ferrochrome
  • Method for preparing chromate by alkaline roasting carbon ferrochrome
  • Method for preparing chromate by alkaline roasting carbon ferrochrome

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Embodiment 1

[0020] Embodiment 1: get the weight 5g of the carbon ferrochrome powder that grinds finely through 300 mesh sieves, mix with heavy 6.2g sodium carbonate mortar, place in muffle furnace, under air atmosphere, be heated up to with the speed of 300 ℃ / min 600°C, keep warm at 600°C for 0.5h, cool naturally, stir and leach with 200ml of deionized water at 30°C for 1h, filter, the recovery rate of chromium is 90.7%. The leaching slag is dried, ground and passed through a 300-mesh sieve, mixed with a 0.65g sodium carbonate mortar, and roasted at 600°C for 0.5h. After leaching, the chromium slag contains 0.02% chromium, and the total recovery rate of chromium is over 99.9%.

Embodiment 2

[0021] Embodiment 2: get the heavy 5g of carbon ferrochrome powder that grinds through 300 mesh sieves, mix with heavy 12.1g potassium carbonate mortar, place in muffle furnace, under air atmosphere, be heated up to with the speed of 300 ℃ / min 1200°C, heat preservation at 1200°C for 2h, cooling naturally, stirring and leaching with 200ml deionized water at 30°C for 1h, filtering, the recovery rate of chromium was 91.1%. The leaching slag is dried, ground and passed through a 300-mesh sieve, mixed with a 1.3g potassium carbonate mortar, and roasted at 1200°C for 4 hours. After leaching, the chromium slag contains 0.01% chromium, and the total recovery rate of chromium is over 99.9%.

Embodiment 3

[0022] Embodiment 3: get the weight 5g of the carbon ferrochrome powder that grinds through 300 mesh sieves, mix with heavy 10.1g potassium carbonate mortar, place in muffle furnace, under air atmosphere, be heated up to with the speed of 300 ℃ / min 800°C, keep warm for 2h, then rise to 1000°C, keep warm for 1h, cool naturally, stir and leach with 200ml deionized water at 30°C for 1h, filter, the recovery rate of chromium is 94.7%. The leaching slag is dried, ground and passed through a 300-mesh sieve, mixed with a 0.98g potassium carbonate mortar, and roasted at 1100°C for 1 hour. After leaching, the chromium slag contains 0.006% chromium, and the total recovery rate of chromium is over 99.9%.

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Abstract

The invention relates to a method for preparing chromate by alkaline roasting carbon ferrochrome, comprising the steps of: after milling the carbon ferrochrome into 300 meshes, mixing the carbon ferrochrome with 80-150% of alkali in a theoretical amount; roasting for 0.4-5h in an air atmosphere under 600-1200 DEG C, cooling, and leaching the chromate by water wherein the primary extraction rate is between 90% and 98%; if the leached residues contain much chromium, mixing the chromium residues with 80-200% of the alkali in the theoretical amount; roasting for 0.5-2h at the air atmosphere under 600-1200 DEG C, cooling, and leaching the chromate by water, wherein the total recovery rate of the chromate can reach up to more than 99.9%, and the content of the chromium contained in leached residues is lower than 0.05%; after simple treatment, discharging. The method is simple in process, low in equipment requirements and little in slag discharging amount; the method can solve the problem of severe pollution in production of the chromate; the prepared chromate products have high purity and can be easily and continuously prepared.

Description

technical field [0001] The invention relates to a method for preparing chemical products, in particular to a method for preparing chromate with less pollution and high product purity. Background technique [0002] The traditional chromate production method is generally to use chromite as raw material, add calcareous filler (limestone and dolomite), mix it with soda ash and some returned slag, and oxidize and roast it in a rotary kiln at 1100-1200 ° C. After roasting The clinker is cooled and leached to obtain a sodium chromate solution, and then neutralized and purified to obtain pure chromate. Due to the introduction of a large amount of calcareous fillers in the above method, not only the amount of slag discharge increases (reaching 2.5-3 tons / ton of product), but also the water-insoluble matter of hexavalent chromium is easily generated, which reduces the dissolution rate of chromium and increases the chromium content. The toxicity of the slag makes the chromium slag ext...

Claims

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Application Information

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IPC IPC(8): C01G37/14
Inventor 彭忠东胡国华
Owner HUNAN JOYFLY TECH DEV
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