Method of removing oxalate from Bayer-process washing liquid

A Bayer method and lotion technology, applied in the field of oxalate removal, can solve the problems of loss of valuable elements, high cost, and high energy consumption for oxalate removal, and achieve rapid response, compact equipment, and stable removal effect

Inactive Publication Date: 2018-01-12
臧海伟
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problems of high energy consumption, high cost, and loss of valuable elements in the prior art for removing oxalate, the present invention provides a method for removing sodium oxalate from the washing liquid produced by the Bayer process

Method used

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  • Method of removing oxalate from Bayer-process washing liquid
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  • Method of removing oxalate from Bayer-process washing liquid

Examples

Experimental program
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Effect test

Embodiment 1

[0023] Example 1 Sodium oxalate was removed from the Bayer process lotion.

[0024] Such as figure 1 As shown in the flow chart, the C 2 O 4 2- Transfer 500 ml of a sample of Bayer lotion with a concentration of 12 g / L to a 1000 ml stainless steel reactor. The temperature of the lotion itself is about 70 ℃, without heating, prepare a sufficient amount of solid alkali, add it to the lotion, stir and mix. Evenly, make Na 2 O k The concentration is 250 g / L, and the final volume of the reaction system is about 580 ml. The sodium oxalate precipitate was separated by filtration to obtain 8.5 g of solid.

Embodiment 2

[0027] Example 2 The effect of removing sodium oxalate.

[0028] The reaction solution in the reaction kettle of Example 1 and Comparative Example 1 before the start of the reaction, and the reaction solution after 30 minutes and 60 minutes of reaction was collected from the reaction kettle to determine Na 2 O T , AO, Na 2 O k With Na 2 C 2 O 4 The results are shown in Table 1 below. The results show that although the conventional lime milk removes sodium oxalate, although it can be effectively removed, the valuable element aluminum is almost completely lost; and with the extension of the causticizing time, the oxalate has reverse dissolution. The method of the invention not only can effectively remove sodium oxalate, but also does not occur the phenomenon of oxalate reverse dissolution, and there is no loss of aluminum, which is a valuable element. The solid filter residues obtained in Example 1 and Comparative Example 1 were subjected to XRD analysis, and the analysis results a...

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Abstract

The invention provides a method of removing oxalate from Bayer-process washing liquid. The method comprises the following steps: adding NaOH into washing liquid so as to crystallize and separate out sodium oxalate; then performing solid-liquid separation to obtain sodium oxalate, wherein the concentration of C2O4<2-> in the washing liquid is 5-15g / l, the concentration of Na2OK in the reaction liquid is 200-300g / l, and the added NaOH is solid or solution. The method provided by the invention effectively reduces the loss of alkali and aluminum oxide, lowers the cost of removing sodium oxalate and obtains a relatively pure sodium oxalate product; the use of lime is avoided, the volume of residues is reduced, and the working conditions are improved; moreover, it is unnecessary to particularlycontrol the alkali liquid in a low-concentration range. The method of removing sodium oxalate provided by the invention is applicable to the technology of producing aluminum oxide from various types of bauxite by a Bayer process, and has a wide application range.

Description

Technical field [0001] The invention belongs to the field of metallurgical engineering, and specifically relates to a method for removing oxalate from a lotion for producing alumina by the Bayer process. Background technique [0002] The bauxite used in the production of alumina by the Bayer process often contains a certain amount of organic carbon. These organic carbons can be divided into two categories: humic acid and asphalt. The latter is insoluble in alkaline solution and all discharged with red mud; while humic acid organic matter generates various sodium humic acid under the action of alkali and high temperature, and then gradually Converted into easily soluble sodium oxalate and sodium carbonate. Sodium carbonate in the solution is removed by a special process, but sodium oxalate accumulates continuously in the solution, and when it reaches supersaturation, it will precipitate with aluminum hydroxide when the temperature is low, and then dissolve in the solution when th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/47
Inventor 臧海伟
Owner 臧海伟
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