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A kind of method of high-concentration evaporation and desalting of seed separation mother liquor

A high-concentration technology of separating mother liquor, which is applied in the preparation of alkali metal aluminate/alumina/aluminum hydroxide, can solve the problems of high-concentration evaporation of mother liquor, achieve complete salt discharge, save steam, and ensure evaporation concentration Effect

Active Publication Date: 2017-08-08
开曼铝业(三门峡)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to propose a method for high-concentration evaporation and desalting of the mother liquor of seed separation. By adopting two-step evaporation, negative pressure steamed water, and mixed desalting technology, it solves the problems in the alumina production process. Evaporation of high concentration of seed separation mother liquor

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  • A kind of method of high-concentration evaporation and desalting of seed separation mother liquor

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Effect test

Embodiment 1

[0030] The composition of the stock solution of the species treated in this embodiment is shown in Table 1.

[0031] Table 1: Example 1 kind of evaporation stoste composition

[0032] Element AL 2 o 3

Nk Nc Nt SiO 2

Nc / Nt NS ak Content (g / L) 43.54 108.81 10.72 119.53 0.22 8.97％ 4.29 4.1

[0033] figure 1 The flow chart of the high-concentration evaporation and desalting of seed separation mother liquor is shown.

[0034] First, the composition such as the seed fraction evaporation stoste of table 1 is evaporated in one step, and the seed fraction stoste is evaporated to Nk 260g / L (with Na 2 (concentration of O meter), then carry out flash evaporation with negative pressure, and the vacuum tightness of flash tank is 0.08MPa, and concentration is brought up to Nk 280g / L, and the one-step evaporation mother liquor concentration of this moment is close to the precipitation concentration of salt, and discharge temperature It i...

Embodiment 2

[0040] Table 2: 2 kinds of evaporation stoste components of embodiment

[0041] Element AL 2 o 3

Nk Nc Nt SiO2 Nc / Nt NS ak Content (g / L) 57.02 122.67 7.2 129.87 0.32 5.54％ 5.21 3.54

[0042] First, carry out one-step evaporation of the seed fraction evaporation stock solution whose composition is as shown in Table 2, evaporate the seed fraction stock solution to Nk 280g / L with a conventional six-effect tube type falling film evaporator, and then carry out flash evaporation with negative pressure, and the vacuum degree is controlled at 0.08 MPa, the concentration is increased to Nk300g / L, at this time, the concentration of the mother liquor is close to the precipitation concentration of the salt, and the discharge temperature is 86°C.

[0043] The one-step evaporation mother liquor obtained by flash evaporation and a part of the high-concentration alkali liquor obtained by two-step evaporation are subjected to plate countercurren...

Embodiment 3

[0048] Table 3: 3 kinds of evaporating stoste components of embodiment

[0049] Element AL 2 o 3

Nk Nc Nt SiO 2

Nc / Nt NS ak Content (g / L) 61.62 130.21 11.26 128.81 0.31 8.74％ 5.02 3.60

[0050] First, carry out the one-step evaporation of the seed fraction evaporation stock solution whose composition is as shown in Table 3, evaporate the seed fraction stock solution to Nk 250g / L with a conventional six-effect tube type falling film evaporator, and then carry out flash evaporation with negative pressure, and the vacuum degree is controlled at 0.08 MPa, the concentration is increased to Nk290g / L, at this time the concentration of the mother liquor is close to the precipitation concentration of the salt, and the discharge temperature is 86°C.

[0051] The one-step evaporation mother liquor obtained by flash evaporation and a part of the high-concentration alkali liquor obtained by two-step evaporation are subjected to plate count...

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Abstract

The invention provides a high-concentration evaporation salt elimination method for a seed precipitation solution.The high-concentration evaporation salt elimination method includes the steps of first-step evaporation, wherein the seed precipitation solution is evaporated through a falling-film evaporator to be 250-280 g / L in Nk, then negative pressure is used for flashing, alkali liquor with the concentration Nk of 270-300 g / L is obtained, and then salt elimination and filtering are conducted; a salt elimination solution obtained after salt elimination is press-filtered through a filter press, wherein the filter press is a plate-and-frame filter press; second-step evaporation, wherein the solution is evaporated to be 500-600 g / L in Nk.Based on the traditional aluminum oxide evaporation technology, the two-step evaporation process is provided, most reasonable performance of operation and investment is achieved, the evaporator which is low in steam consumption and small in investment and is made of a conventional material is adopted in first-step evaporation, the water amount is evaporated by 80% or above, the alkali-resisting nickel evaporation which is high in investment and high in steam consumption is adopted for evaporating remaining water in second-step evaporation, and the high-concentration seed precipitation solution is obtained.

Description

technical field [0001] The invention belongs to the field of alumina production, and in particular relates to a method for evaporating high-concentration seed separation mother liquor. Background technique [0002] Evaporation of mother liquid (decomposed seed crystal) is a key link in the alumina production process. It not only determines the energy consumption of alumina, but also has a great impact on the cycle efficiency of the system. In recent years, with the development of tubular falling film evaporators The application in alumina production has greatly reduced the energy consumption of the evaporation process, and the old-fashioned shell and tube evaporator has been basically eliminated. However, due to the existence of various salts (mainly sodium carbonate) in the mother liquor of alumina species ), with the evaporation of the mother liquid concentration of the seed fraction, the precipitation of these salts is very obvious, resulting in serious plugging of the tu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/14
CPCC01F7/14
Inventor 张广麻树春马淑花
Owner 开曼铝业(三门峡)有限公司