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Process of preparing sodium chromate product without calcium

A preparation process, calcium sodium chromate technology, applied in chromate/dichromate and other directions, can solve the problems of high cost, large slag output, difficult to handle, etc., and achieves low production cost, low environmental pollution, and equipment. small investment

Inactive Publication Date: 2007-11-07
张天成
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, the production of sodium chromate in our country adopts calcium roasting, that is, dolomite, slaked lime, soda ash and chromite are mixed first, then calcined in a roasting brick kiln, and sodium chromate is produced by crushing, filtering and leaching. The disadvantages are high cost, high energy consumption, and a large amount of slag, generally 2.5-3 tons of slag per ton of sodium chromate
And the slag is difficult to handle and highly polluting
Most foreign countries use calcium-free roasting technology, but the process is complicated and the investment is high. In recent years, there have been calcium-free technology in China, which is to use chromite and alkali mixed firing, but this processing method adds oxidants, and it is easy to sinter in the kiln.

Method used

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  • Process of preparing sodium chromate product without calcium

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Send 1,000 kg of 150-mesh chromite powder into the rotary kiln and calcinate at 1250°C for 30 minutes; the calcined chromite powder is transferred out and mixed with 720 kg of soda ash; the mixed chromite and soda ash mixture is re- Send it to the rotary kiln for calcination and slaking; then sort out the unreacted materials in the mixture after calcination and slaking and mix them with chromite for repeated use; crush the slags of the slaking good materials into small particles of 3 meshes; The material is soaked in water, stirred, precipitated, and the slag is removed to obtain a sodium chromate solution; the chromium slag after the material is leached and precipitated can be mixed with chromite ore and reused.

Embodiment 2

[0017] Send 1,000 kg of 200-mesh chromite powder into the rotary kiln and calcinate at 1300°C for 90 minutes; transfer the calcined chromite powder and mix it with 800 kg of soda ash; mix the chromite and soda ash mixture again Send it to the rotary kiln for calcination and slaking; then sort out the unreacted materials in the mixture after calcination and slaking and mix them with chromite for reuse; crush the slags of the slags into 8-mesh small particles; The material is soaked in water, stirred, precipitated, and the slag is removed to obtain a sodium chromate solution; the chromium slag after the material is leached and precipitated can be mixed with chromite ore and reused.

Embodiment 3

[0019] Send 1,000 kg of 160-mesh chromite powder into the rotary kiln and calcinate at 1260°C for 40 minutes; transfer the calcined chromite powder and mix it with 750 kg of soda ash; mix the chromite and soda ash mixture again Send it to the rotary kiln for calcination and slaking; then sort out the unreacted materials in the mixture after calcination and slaking and mix them with chromite for repeated use; crush the slags of the slags into 5-mesh small particles; The material is soaked in water, stirred, precipitated, and the slag is removed to obtain a sodium chromate solution; the chromium slag after the material is leached and precipitated can be mixed with chromite ore and reused.

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Abstract

The present invention discloses process of preparing sodium chromate product without calcium, and sodium chromate solution is prepared through calcining, hot mixing, calcining to cure, sorting, crushing and leaching. The preparation process has low investment, simple operation, no sintering step, less slag, low power consumption, low production cost, less environmental pollution and other advantages.

Description

technical field [0001] The invention relates to a preparation process of sodium chromate, in particular to a preparation process of hot-mixed calcium-free sodium chromate. Background technique [0002] At present, the manufacture of sodium chromate in our country adopts calcium roasting, which is to mix dolomite, slaked lime, soda ash and chromite ore first, then calcinate in a brick kiln, and then produce sodium chromate through crushing, filtration and leaching. The disadvantages are high cost, high energy consumption, and a large amount of slag, generally 2.5-3 tons of slag per ton of sodium chromate. And the slag is difficult to handle and highly polluting. Most foreign countries use calcium-free roasting technology, but the process is complicated and the investment is high. In recent years, there have been calcium-free technology in China, which is to use chromite and alkali mixed firing, but this processing method adds oxidants, and it is easy to sinter in the kiln. ...

Claims

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Application Information

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IPC IPC(8): C01G37/14
Inventor 张天平张天成
Owner 张天成
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