Method for producing sodium chromate through calcium-free enriched oxygen or pure oxygen roasting

A sodium chromate and oxygen-enriched technology, which is applied in the direction of chromate/dichromate, etc., can solve the problems of introducing impurities, high production cost, poor process indicators, etc., and achieve less slag discharge, high chromium conversion rate, The effect of rapid roasting reaction

Inactive Publication Date: 2017-03-15
GANSU JINSHI CHEM
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Problems solved by technology

[0002] At present, there are generally poor process indicators and high production costs in the production of chromium salt calcium-free roasting rotary kilns at home and abroad.
However, the current technology for the production of chromium salts by calcium-free roasting uses catalysts such as chromic anhydride, monazite or manganese ore in the roasting materials to achieve the purpose of improving roasting efficiency, but adding additives is easy to introduce impurities into the subsequent return slag

Method used

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  • Method for producing sodium chromate through calcium-free enriched oxygen or pure oxygen roasting

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Experimental program
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Effect test

Embodiment 1

[0033] According to the mass ratio of chromite: soda ash: return slag = 25:15:60, the batching is put into the kiln tail of the rotary kiln. The residence time of the material in the kiln is about 3 hours. Coal-injection combustion, oxygen-enriched air (oxygen content 40-50%) is blown into the high-temperature zone of the kiln head, and the blast volume is 5.8 tons of oxygen-enriched air according to the ton of coal burned (the blast volume is measured by pressure gauges and flow meters). After roasting, the water-soluble sodium chromate of the clinker is 14.8%, and there is no ring formation in the kiln, and the calculated chromium conversion rate is 88.6%. After crushing and wet leaching, the final calculated slag discharge is 0.66 tons per ton of product.

[0034] Compared with the traditional calcium-free roasting production process (the blast at the kiln head is air), the amount of coal injection per ton of product is 1.0 tons, the residence time of the material in the ro...

Embodiment 2

[0036] According to the mass ratio of chromite: soda ash: return slag = 25:15:60, the batching is put into the kiln tail of the rotary kiln. The residence time of the material in the kiln is about 2.5 hours. Coal-injection combustion, pure oxygen (oxygen content greater than 95%) is blown into the high-temperature zone of the kiln head, and the blast volume is 2 tons of pure oxygen according to the ton of coal burned (the blast volume is measured by pressure gauges and flow meters). After roasting, the water-soluble sodium chromate of the clinker is 15.2%, and there is no ring formation in the kiln, and the calculated chromium conversion rate is 90.4%. After crushing and wet leaching, the final calculated slag discharge is 0.62 tons per ton of product.

[0037] Compared with the traditional calcium-free roasting production process (the blast at the kiln head is air), the amount of coal injection per ton of product is 1.0 tons, the residence time of the material in the rotary k...

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Abstract

The invention discloses a method for producing sodium chromate through calcium-free enriched oxygen or pure oxygen roasting, mainly aims to solve problems that conventional calcium-free roasting rotary kiln production in China and outer countries is relatively low in chromium conversion rate, long in kiln material reaction time, relatively high in roasting temperature and the like, and aims to achieve the purposes that through enriched oxygen roasting (or pure oxygen roasting), the reaction velocity is increased, the chromium conversion rate is increased, the energy consumption is reduced, the waste residue discharge is reduced, the production efficiency is improved and the cost is lowered.

Description

technical field [0001] The invention relates to the field of chromium salt production, in particular to a method for producing sodium chromate by calcium-free oxygen-enriched or pure oxygen roasting. On the basis of the original calcium-free roasting process, according to the roasting reaction mechanism, oxygen-enriched roasting is carried out in the roasting high temperature zone. Or pure oxygen, to speed up the conversion rate of roasting reaction, to increase the reaction rate and roasting conversion rate, reduce the amount of coal injection and slag discharge, improve production efficiency, and reduce production costs. Background technique [0002] At present, there are generally poor process indicators and high production costs in the production of chromium salt calcium-free roasting rotary kilns at home and abroad. The current technology for calcium-free roasting to produce chromium salts uses catalysts such as chromic anhydride, monazite or manganese ore in the roasti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/14
CPCC01G37/14
Inventor 韩登仑张忠元谢希智杨昆山毛雪琴
Owner GANSU JINSHI CHEM
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