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Roasting method for producing sodium chromate using chrome iron ore

A technology of chromite and sodium chromate, which is applied in the direction of chromate/dichromate, etc., can solve the problems of difficult filtration and washing, pollution of the environment, serious slag belt damage, etc., and achieve clinker performance and filtration and washing performance Effects of improving, increasing utilization, and reducing costs

Inactive Publication Date: 2005-09-14
TIANJIN CHEM RES & DESIGN INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of insoluble chromium generated during roasting and leaching of chromite, difficulty in filtering and washing, serious slag damage and environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0027] Weigh and crush the 200 mesh sieve containing Cr 2 o 3 Add 10g of 53.6% chromite, add 15g of sodium carbonate, 18g of magnesite, and mix well. Roasting at 1150°C for 40 minutes, the clinker is sandy, the transfer rate is 99.65%, and the acid-soluble hexavalent chromium is 0.02%.

example 2

[0029] Weigh and crush the 200 mesh sieve containing Cr 2 o 3 Add 10g of 52.1% chromite, add 8g of sodium carbonate, 20g of magnesite, 10g of returned slag, and mix well. Roasting at 1150°C for 30 minutes, the clinker is sandy, the transfer rate is 99.3%, and the acid-soluble hexavalent chromium is 0.04%.

example 3

[0031] Weigh and crush the 200 mesh sieve containing Cr 2 o 3 Add 10g of 45.3% chromite, add 8g of sodium carbonate, 40g of magnesite, and mix well. Roasting at 1100°C for 60 minutes, the clinker is sandy, the transfer rate is 98.91%, and the acid-soluble hexavalent chromium is 0.048%.

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Abstract

The method for preparing sodium chromate by calcining chromite includes the following steps: pulverizing chromite and sieving with 200 mesh sieve, adding sodium carbonate whose added amount is 80-150% of chromite amount, and adding magnesite, baudisserite, periclase, brucite or synthetic magnesium oxide, magnesium hydroxide and magnesium carbonate and calcining them at 1000-1200 deg.c for 10-60 min. under the condition of oxidation atmosphere, then extracting clinker and dissolving sodium chromate so as to obtain the goal of preparing sodium chromate. The conversion rate of chromite can be up to 97-99.5%.

Description

technical field [0001] The invention belongs to the technical field of inorganic synthesis, and more specifically relates to a process method for roasting chromite ore with calcium-free filler. Background technique [0002] Sodium chromate is prepared from chromite ore, generally by adding an appropriate amount of sodium carbonate to chromite ore, then adding an appropriate amount of limestone, dolomite and slag, and mixing. Roasted at 1100-1200°C in a rotary kiln. The clinker is leached, and the sodium chromate is transferred into the solution to achieve the purpose of preparing sodium chromate. According to the traditional process, when chromite is roasted, the amount of calcium oxide added must be close to the amount calculated by the empirical formula. If the amount of calcium oxide is insufficient, the oxidation rate of chromite will decrease, which will directly affect the chromium yield. But above-mentioned method, owing to have added the filler that contains a larg...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G37/14
Inventor 杨振祥
Owner TIANJIN CHEM RES & DESIGN INST
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