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Method for calcium-free calcination production of sodium chromate and chromium-containing cast iron as co-product

A calcium-free roasting and sodium chromate technology, applied in the direction of chromate/dichromate, etc., can solve the problems of large energy loss and low roasting efficiency, and achieve product quality improvement, comprehensive utilization rate improvement, and production capacity increase big effect

Inactive Publication Date: 2013-07-31
INNER MONGOLIA CHROMIUM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a clean multi-stage calcium-free roasting method for producing sodium chromate and co-production of chromium-containing cast iron, so as to solve the problems of low roasting efficiency and large energy loss in the existing calcium-free roasting production of chromium salts

Method used

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  • Method for calcium-free calcination production of sodium chromate and chromium-containing cast iron as co-product
  • Method for calcium-free calcination production of sodium chromate and chromium-containing cast iron as co-product

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] The following is an example of the production of sodium chromate and co-production of chromium-containing cast iron by oxygen-enriched roasting, wherein the composition of the chromium ore used is as shown in table 1

[0019] The chromite composition that adopts in the embodiment 1 of table 1

[0020] Cr 2 o 3

FeO

MgO

Al 2 o 3

SiO 2

CaO

V 2 o 5

Na 2 o

44.01%

25.64%

9.87%

16.23%

2.09%

1.0%

0.16%

0.01%

[0021] see figure 1 The process of producing sodium chromate and co-producing chromium-containing cast iron by oxygen-enriched roasting includes:

[0022] A roasting process: 3.4 tons of chromite (ground to 200 mesh with a pass rate greater than 95%) and 1 ton of soda ash (Na 2 CO 3 content: 98.62%) and mixed evenly; put it into a rotary kiln for roasting at a temperature of 1100-1200 ° C, and feed 0.42 tons of oxygen, and the material stays in the kiln for 150 minutes withou...

Embodiment 2

[0037] This example is an example of the production of sodium chromate and the co-production of chromium-containing cast iron by the air roasting process, wherein the composition of the chromium ore used is shown in Table 5.

[0038] The chemical composition of chromite in table 5 embodiment 2

[0039] Cr 2 o 3

FeO

MgO

Al 2 o 3

SiO 2

CaO

V 2 o 5

Na 2 o

44.5%

26.2%

11.2%

14.4%

2.6%

0.7%

0.16%

0.01%

[0040] The process of air roasting to produce sodium chromate and co-production of chromium-containing cast iron includes:

[0041] A roasting process: 3.4 tons of chromite (ground to 200 mesh with a pass rate greater than 95%) and 1.2 tons of soda ash (Na 2 CO 3 content: 98.62%) and mix evenly; put it into a rotary kiln for roasting at a temperature of 1100-1200 ℃, and let in air so that the material does not form a wall, and clinker is obtained. The clinker processing method obtained...

Embodiment 3

[0056] Comprehensive utilization of the three slags.

[0057] Mix the calcium-free chromium slag with the chromite block at a ratio of 1:3.55, and then add semi-coke, silica, etc. into the reduction furnace for smelting. The ratio of raw materials is shown in Table 9:

[0058] Table 9 uses the three-stage roasting filter slag to carry out the batching ratio of high-carbon ferrochrome smelting

[0059]

[0060] A total of 21 batches of products were obtained in this group of tests, and about 20 batches of materials were fed into each batch, and an average of 4.9 tons of high-carbon ferrochromium was obtained per batch, and 6.0 tons of electric furnace slag was produced.

[0061] Wherein, the chrome ore composition used is as shown in table 10:

[0062] Table 10 Chemical composition of chromite for smelting chromium-containing cast iron test

[0063] Cr 2 o 3

[0064] Among them, the blue carbon composition includes 80% C, 14% ash, 5% volatile matter, and the ...

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Abstract

The invention discloses a method for calcium-free calcination production of sodium chromate and chromium-containing cast iron as a co-product. The method comprises the following steps of 1, first-stage calcination by mixing chromite and soda ash according to a certain ratio to obtain a first-stage mixed material, wherein a soda ash use amount is 35-60% of the theoretical alkali use amount, putting the first-stage mixed material into a rotary kiln, carrying out oxidizing calcination, and carrying out impregnation and filtration of the calcined clinker to obtain a first-stage sodium chromate alkali solution and filter residues, and 2, treating the filter residues, and carrying out second-stage calcination and third-stage calcination of the filter residues by the step 1 to obtain second-stage calcination filter residues, third-stage calcination filter residues, a second-stage calcination sodium chromate alkali solution and a third-stage calcination sodium chromate alkali solution, wherein the third-stage calcination filter residues can be used for co-production of chromium-containing cast iron. The method does not adopt any auxiliary materials in calcination, and effectively avoids ring forming of the rotary furnace. The calcination residues obtained by the method does not contain hexavalent chromium compounds and thus chromium residue harmlessness and recycling are realized. Through co-production of high-carbon chromium iron, a chromium comprehensive use ratio is improved by more than 95%. Through smelting, produced electroslag does not contain hexavalent chromium so that thorough detoxification of chromium residues is realized.

Description

technical field [0001] The invention belongs to the field of chromium salt production and relates to a method for producing sodium chromate and co-producing chromium-containing cast iron by three-stage calcium-free roasting. Background technique [0002] The chromium salt industry is one of the most competitive resource raw material industries in the world. Chromium salt products are used in metallurgy, pigments, leather, dyes, spices, metal surface treatment, welding electrodes, coinage, catalysts, printing and dyeing, medicine and other industries has wide application. With the deepening of my country's reform and opening up and the rapid development of the economy, the demand for chromium salt products is increasing day by day, and the development prospect of the chromium salt industry is broad. [0003] However, the traditional chromium salt production process with a history of more than one hundred years severely restricts the development of chromium salt enterprises d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/14C21B13/00
Inventor 张轶
Owner INNER MONGOLIA CHROMIUM
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