Method for crystal seed precipitation of sodium aluminate solution

A sodium aluminate and solution technology, applied in the field of sodium aluminate solution seed crystal decomposition, can solve the problems of complex process, high cost, no obvious effect of decomposition rate, etc., and achieves the advantages of improving particle size distribution, increasing energy consumption, and improving decomposition rate. Effect

Active Publication Date: 2013-03-20
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These methods can effectively improve the decomposition rate, but the process is complicated and the cost is high
4) The use of additives, in industry, this type of method is effective for improving product quality, but has no obvious effect on improving the decomposition rate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] The composition of the decomposed stock solution is: the concentration of caustic alkali is Na 2 o k 170g / L, carbon alkali concentration Na 2 o c 5g / L, SiO 2 The concentration is 0.60g / L, and the caustic ratio is 1.45. Decomposition conditions: the seed coefficient is 3.72; the initial temperature of decomposition is 60°C, and the temperature is lowered at a uniform rate, and the temperature is lowered to 40°C in 40 hours. At this time, the caustic ratio of the sodium aluminate solution is 3.05, and the decomposition rate is 52.46%; then, the temperature is continuously raised After 12 hours, the temperature was raised to 65°C, and the decomposition was completed. At this time, the caustic ratio of the sodium aluminate solution was 3.44, and the decomposition rate was 57.85%. In the case of other conditions being the same, a comparative experiment without heating up in the later stage was carried out, that is, the initial temperature was 60°C, and the temperature ...

Embodiment 2

[0014] The composition of the decomposed stock solution is: caustic alkali concentration Na 2 o k 158g / L, carbon alkali concentration Na 2 o c 5g / L, SiO 2 The concentration is 0.70g / L, and the caustic ratio is 1.25. Decomposition conditions: the seed crystal coefficient is 1.0; the initial temperature of decomposition is 80°C, and the temperature is lowered at a uniform rate, and the temperature is lowered to 50°C in 40 hours. At this time, the caustic ratio of the sodium aluminate solution is 2.24, and the decomposition rate is 44.20%; then, the temperature is continuously raised After 5 hours, the temperature was raised to 60°C, and the decomposition was completed. At this time, the caustic ratio of the sodium aluminate solution was 2.53, and the decomposition rate was 50.59%. In the case of other conditions being the same, a comparative experiment without heating up in the later stage was carried out, that is, the initial temperature was 80°C, and the temperature was l...

Embodiment 3

[0016] The composition of the decomposed stock solution is: caustic alkali concentration Na 2 o k 167g / L, carbon alkali concentration Na 2 o c 5g / L, SiO 2 The concentration is 0.62g / L, and the caustic ratio is 1.30. Decomposition conditions: the seed crystal coefficient is 4.0; the initial temperature of decomposition is 70°C, and the temperature is lowered at a uniform rate, and the temperature is lowered to 40°C in 36 hours. At this time, the caustic ratio of the sodium aluminate solution is 2.93, and the decomposition rate is 55.63%; The measure of post-insulation is to raise the temperature to 50°C within 1 hour, and keep it at this temperature for 20 hours until the decomposition is completed. At this time, the caustic ratio of the sodium aluminate solution is 3.52, and the decomposition rate is 63.07%. In the case of other conditions being the same, a comparative experiment without heating up in the later stage was carried out, that is, the initial decomposition tem...

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Abstract

The invention discloses a method for crystal seed precipitation of a sodium aluminate solution, comprising the following steps of: 1), mixing a sodium aluminate solution with Al(OH)3 crystal seeds, starting to stir and precipitate at 60 DEG C to 80 DEG C, wherein the causticity ratio of the sodium aluminate solution is 1.25 to 1.60 and the crystal seed coefficient is 1.0 to 4.0; 2), cooling the precipitation system to 40-50 DEG C; and 3), continuously heating the precipitation system within 5 hours to 20 hours, wherein the heating amplitude is 5 DEG C to 25 DEG C, and the final temperature is not higher than 65 DEG C. By adoption of the method provided in the invention, the crystal seed precipitation process of the sodium aluminate solution is effectively reinforced, and the technical and economical indexes of yield in the precipitation, cycle efficiency of aluminium oxide production, and the like are improved.

Description

technical field [0001] The invention relates to a method for decomposing sodium aluminate solution seed crystals. Background technique [0002] my country is currently the world's largest producer and consumer of alumina. In 2011, the actual output of alumina in my country reached 34.07 million tons, of which more than 90% of the output was prepared by decomposition of sodium aluminate solution seed crystals. The decomposition of sodium aluminate solution seed crystals is a key link that affects the production efficiency and product quality of alumina. Strengthening the decomposition process of sodium aluminate solution seed crystals has always been one of the hot issues in the research of alumina production technology, mainly including two aspects: improving product quality and increasing decomposition rate. [0003] In terms of improving product quality, with the goal of producing sandy alumina, there are currently two main schools in the world: one is the two-stage decom...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/14
Inventor 李小斌刘桂华阎丽杨帅帅彭志宏周秋生齐天贵
Owner CENT SOUTH UNIV
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