Method for treating gibbsite by using high-concentration alkali liquor under normal pressure

A gibbsite ore and atmospheric pressure treatment technology, which is applied in the direction of alumina/hydroxide, etc., can solve the problems of high energy consumption, large amount of evaporated water of the mother liquor of seed separation, and difficulty in liquid-solid separation

Active Publication Date: 2012-06-20
中铝山东有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method also has the disadvantages of high concentration of lye, difficulty in liquid-solid separation, and a large amount of evaporated water from the mother liquor, resulting in high energy consumption.

Method used

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  • Method for treating gibbsite by using high-concentration alkali liquor under normal pressure
  • Method for treating gibbsite by using high-concentration alkali liquor under normal pressure
  • Method for treating gibbsite by using high-concentration alkali liquor under normal pressure

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Take 550g of 40% sodium hydroxide solution and 300g of gibbsite ore with particle size≤106μm (the molecular ratio in the eluate is α K =5.18), stirring and mixing in the alkali-resistant reactor, heating to 140°C at the same time, and holding the heat for 30 minutes to make the components in the bauxite fully react with the lye to obtain a slurry containing sodium aluminate. Cool the dissolution slurry to about 100°C, and use a magnetic separation classifier for preliminary separation: the separated solid slag is added to 60°C water for leaching, and then further liquid-solid separation is obtained to obtain high-iron red mud, and the leachate enters the desiliconization process; after magnetic separation and separation The solution is seeded with solid sodium aluminate and crystallized by cooling to obtain Na 2 (Al 2 o 3 (OH) 2 )1.5H 2 O solid, the crystallization mother liquor returns to the stripping process to continue stripping bauxite trihydrate, and the sodiu...

Embodiment 2

[0033] In an alkali-resistant reactor, stir and mix 600g of 45% sodium hydroxide solution and 300g of gibbsite ore with a particle size of ≤150μm (the molecular ratio in the eluate is α K =5.64), stir the mixture in the reactor and heat it to 135°C, and keep it warm for 30 minutes to fully react the alumina and sodium hydroxide in the bauxite to obtain a slurry containing sodium aluminate. Lower the elution slurry to about 100°C, and use a magnetic separation classifier for preliminary separation: the separated solid slag is added to the washing water for leaching, and then further separated to obtain high-iron red mud, and the leaching solution enters the desiliconization process; the solution after magnetic separation and separation is used Solid sodium aluminate is used as seed crystal, after cooling and crystallization, the crystallization mother liquor returns to the dissolution process to continue to dissolve bauxite trihydrate, sodium aluminate crystallization is mixed w...

Embodiment 3

[0038] In an open steel reaction kettle, stir and mix 1000g of 39% sodium hydroxide solution and 500g of gibbsite ore with a particle size below 106μm (the molecular ratio in the eluate is α K =4.95), heated to 140°C in the reactor, added 20g of pure Ca(OH) 2 (molar ratio [CaO:SiO 2 ]=1.5), and stir for 20 minutes to fully react each component of bauxite with sodium hydroxide to obtain a slurry containing sodium aluminate. Reduce the slurry to about 100°C, and use a magnetic separation classifier for preliminary separation: the separated solid slag is added to 80°C water for leaching, and then further separated to obtain high-iron red mud, and the leachate enters the desiliconization process; the solution after magnetic separation is used Solid sodium aluminate is used as seed crystal, after cooling and crystallization, the crystallization mother liquor is returned to the dissolution process to continue to dissolve bauxite trihydrate, sodium aluminate crystallization is mixed...

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Abstract

The invention discloses a method for treating gibbsite by using high-concentration alkali liquor under normal pressure. The method comprises the following steps of: stirring and uniformly mixing a high-concentration NaOH solution and high-iron gibbsite in an alkali-resistant reactor, heating to the temperature of between 110 and 140 DEG C under normal pressure, and performing primary separation on digestion slurry by using a magnetic separation grader; leaching the obtained solid slag at the temperature of 65 DEG C by using a small amount of water, and performing further liquid-solid separation to obtain high-iron red mud; performing cooling crystallization on a solution obtained after magnetic separation, returning a mother solution to the digestion process, adding a sodium aluminate crystal into a seed decomposition mother solution, redissolving to obtain a sodium aluminate solution, adding Bayer process red mud, lime and the like into the sodium aluminate solution, and performing desilication twice to obtain a sodium aluminate fine solution with the aluminum-to-silicon ratio of 145 to 180 and the molar ratio alphaK of sodium oxide to aluminum oxide of 1.45 to 1.55; and decomposing the fine solution by a Bayer process under the conventional conditions, and performing liquid-solid separation to obtain aluminum hydroxide particles and the seed decomposition mother solution. The seed decomposition mother solution is not evaporated and is returned to the process after aluminum salt and coarse hydrogen and aluminum are dissolved in the seed decomposition mother solution, so that the defect of large water evaporation amount caused by a large concentration difference is overcome.

Description

technical field [0001] The invention relates to a method for producing alumina, in particular to a method for treating gibbsite ore with high-concentration alkaline solution under normal pressure. Background technique [0002] The main resource of alumina production - bauxite, can be divided into gibbsite type, boehmite type, diaspore type and mixed type. They mainly contain compounds of impurities such as Fe, Ti, Si, etc. For imported bauxite, low-temperature Bayer process at 100-150°C is commonly used in industry, and most of the gibbsite dissolves into the solution, while impurity compounds such as Fe, Ti, and quartz are generally insoluble in 200g / L of caustic solution, but into the red mud. During the dissolution process, due to the existence of aluminum goethite, all the alumina cannot enter the solution, and the dissolution rate is only about 85%, and the iron oxide content in the red mud only accounts for about 60%. For boehmite type, diaspore type and mixed typ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
Inventor 杨会宾李韶辉郑秀芳胡剑姜梅王晓锋徐宏刚
Owner 中铝山东有限公司
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