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Method for removing sodium sulfate in aluminum oxide production process

A production process, technology of alumina

Active Publication Date: 2008-05-21
GUIZHOU BRANCH CHINA ALUMINUM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The Research Institute of Shandong Aluminum Company has conducted research on the desulfurization of lime and sodium sulfate-containing solution. The results show that only at a lower solution concentration can there be a good desulfurization effect, and the desulfurization product will take away alumina, resulting in the loss of alumina. loss

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The main component of crystallization containing sodium sulfate in the alumina production process (percentage by weight): Na 2 SO 4 43.4%, Na 2 CO 3 31.3%, Na 2 O8.7%, Al 2 o 3 3.2%; reducing agent coal powder contains 62% fixed carbon; limestone powder is chemically pure CaCO 3 .

[0025] Contain crystals by Na 2 SO 4 The content of calcium carbonate and carbon powder are mixed evenly in a ratio of 1:1.3:2 (molecular ratio), formed into balls, heated to 650°C in a muffle furnace, kept for 90 minutes, then cooled to 200°C and taken out, which is clinker. Clinker composition: S 2- 6.74%; SO 4 2- 3.67%; S T 7.96%. SO 4 2- The reduction rate is 84.7%.

[0026] Take 10 grams of the above-mentioned sintered clinker, add 80 grams of water (80 ml), keep the temperature at 65 ° C, stir and dissolve for 30 minutes, filter the residue, wash and dry. Residue composition: S 2- 16.4%; SO 4 2-1.45%. The residue sulfur removal rate is 65.9%.

Embodiment 2

[0028] The main component of crystallization containing sodium sulfate in the alumina production process (percentage by weight): Na 2 SO 4 43.4%, Na 2 CO 3 31.3%, Na 2 O8.7%, Al 2 o 3 3.2%; reducing agent coal powder contains 62% fixed carbon; limestone powder is chemically pure CaCO 3 .

[0029] Contain crystals by Na 2 SO 4 The content of calcium carbonate and carbon powder are mixed in a ratio of 1:1.3:2 (molecular ratio), packed in a porcelain crucible, covered, heated to 850°C in a muffle furnace, kept for 30 minutes, and then cooled When it is taken out at 200°C, it becomes clinker. Clinker composition: S 2- 6.88%; SO 4 2- 2.98%; S T 7.87%. SO 4 2- The reduction rate is 87.4%.

[0030] Take 10 grams of the above-mentioned sintered clinker, add 50 grams of water (50ml), keep the temperature at 30°C, stir and dissolve for 50 minutes, filter the residue, wash and dry. Residue composition: S 2- 16.1%; SO 4 2- 1.11%. The residue sulfur removal rate is 69...

Embodiment 3

[0032] The main component of crystallization containing sodium sulfate in the alumina production process (percentage by weight): Na 2 SO 4 43.4%, Na 2 CO 3 31.3%, Na 2 O8.7%, Al 2 o 3 3.2%; reducing agent coal powder contains 62% fixed carbon; limestone powder is chemically pure CaCO 3 .

[0033] Contain crystals by Na 2 SO 4 The content of calcium carbonate and carbon powder are mixed evenly in a ratio of 1:1:2 (molecular ratio), formed into balls, heated to 800°C in a muffle furnace, kept for 60 minutes, then cooled to 250°C and taken out, which is clinker. Clinker composition: S 2- 6.79%; SO 4 2- 3.24%;S T 7.87%. SO 4 2- The reduction rate is 86.3%.

[0034] Take 10 grams of the above-mentioned sintered clinker, add 100 grams of water (100 ml), keep the temperature at 50° C., stir and dissolve for 40 minutes, filter the residue, wash and dry. Residue composition: S 2- 14.9%; SO 4 2- 1.3%. The residue sulfur removal rate is 62.3%.

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Abstract

The invention discloses a method for removing sodium sulfate in the production process of alumina, relating to a technology for removing sodium sulfate from crystals containing sodium sulfate after evaporation of sodium aluminate solution. It is characterized in that the process of removing sodium sulfate is to reduce the crystalline Na2SO4 in the alumina production process with carbon in the presence of calcium carbonate, so that sulfur can be removed as calcium sulfide, and sodium can be recycled into sodium carbonate. The method of the invention can make the removal rate of sulfur in the sodium sulfate reach more than 60%, and the sodium can be recovered in the form of sodium carbonate.

Description

technical field [0001] The invention discloses a method for removing sodium sulfate in the production process of alumina, relating to a technology for removing sodium sulfate from crystals containing sodium sulfate after evaporation of sodium aluminate solution. Background technique [0002] In the process of alumina production, the sulfur brought in by pyrite and colloidal pyrite in the raw material bauxite, and the sulfide brought in by fuel oil and coal will all react with the sodium aluminate solution to form sulfide , Thiosulfate, sulfate, etc. are continuously accumulated in the production process. The accumulation of sulfur in the production process will reduce the decomposition rate of species; the accumulation of sulfide to a certain extent will cause the concentration of soluble iron in the solution to increase and affect product quality; the sulfur of sulfide and thiosulfate will intensify the damage to steel corrosion; sulfur eventually turns into sodium sulfate...

Claims

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Application Information

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IPC IPC(8): C01F7/46C01D7/00
Inventor 白万全刘汝兴
Owner GUIZHOU BRANCH CHINA ALUMINUM IND
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