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A method for preparing sandy alumina

A technology of alumina and aluminum hydroxide, applied in the field of aluminum metallurgy, can solve the problems that boehmite technology cannot be industrialized, it is difficult to meet the problems of sandy alumina, and the decomposition rate of boehmite is low, and it is beneficial to aluminum Electrolysis, easy industrial implementation, saving effect of roasting energy consumption

Active Publication Date: 2017-01-04
CENT SOUTH UNIV
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  • Abstract
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Problems solved by technology

But at high temperature, the decomposition rate of boehmite precipitated in supersaturated sodium aluminate solution is low; adding organic matter can increase the decomposition rate of boehmite, but the particle size is fine, which is difficult to meet the requirements of sandy alumina
Thereby, present kind of analyzing boehmite technology also can't be industrialized
[0006] In summary, when the species is analyzed to produce aluminum hydroxide, there is a contradiction between improving the product decomposition rate and product quality; although the roasting energy consumption is low when the boehmite is precipitated, the species decomposition rate is low and the product quality is low. Poor, these make the seed sorting process is still the bottleneck of improving the efficiency of alumina production

Method used

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  • A method for preparing sandy alumina
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Embodiment 1

[0035] The preparation method of sandy alumina of the present invention, technological process such as figure 1 As shown, take 40ml supersaturated sodium aluminate solution (Na 2 O=162g / L, Al 2 o 3 =187.2g / L, α k =1.42), add 50ml sodium bicarbonate suspension (NaHCO 3 =45g / L), stirred at 30°C for 60min to obtain activated aluminum hydroxide seeds.

[0036] 900ml supersaturated sodium aluminate solution (Na 2 O=162g / L, Al 2 o 3 =187.2g / L, α k=1.42) into the seeding tank, add the active aluminum hydroxide crystal seed prepared above while stirring, start a section of seeding, a section of seeding adopts constant temperature decomposition, the decomposition temperature is 45 ° C, and end a section of seeding after 40 hours of decomposition , filter the slurry after seed separation to obtain a section of seed separation mother liquor and aluminum hydroxide. Aluminum hydroxide is washed to obtain a decomposed aluminum hydroxide. The average particle size d of the aluminum...

Embodiment 2

[0040] The preparation method of sandy alumina of the present invention, technological process such as figure 1 As shown, take 50ml supersaturated sodium aluminate solution (Na 2 O=151g / L, Al 2 o 3 =188.9g / L, α k =1.31), add 50ml sodium bicarbonate suspension (NaHCO 3 =35g / L), stirred at 25°C for 30min to obtain activated aluminum hydroxide seeds.

[0041] Add 900ml of supersaturated sodium aluminate solution into the seeding tank, add the above-prepared activated aluminum hydroxide seed crystals while stirring, start a section of seeding, and use cooling to decompose for a section of seeding, decompose at 50°C for 10 hours and then drop to 45°C, decompose for another 30 hours, filter the slurry after the seed separation, and obtain a section of seed separation mother liquor and aluminum hydroxide. Aluminum hydroxide is washed to obtain a decomposed aluminum hydroxide. The average particle size d of the decomposed aluminum hydroxide 50 =12.1μm, Na in the product 2 The ...

Embodiment 3

[0045] The preparation method of sandy alumina of the present invention, technological process such as figure 1 As shown, take 30ml supersaturated sodium aluminate solution (Na 2 O=165g / L, Al 2 o 3 =180.6g / L, α k =1.50), adding 50ml concentration of 10% hydrogen peroxide, stirred at 30°C for 60min to obtain active aluminum hydroxide seed crystals.

[0046] Add 900ml of supersaturated sodium aluminate solution into the seeding tank, add the above-prepared activated aluminum hydroxide seed crystals while stirring, start a section of seeding, and decompose at a constant temperature for a section of seeding at 55°C for 40 hours Finally, a section of seed separation is completed, and the slurry after seed separation is filtered to obtain a section of seed separation mother liquor and aluminum hydroxide. Aluminum hydroxide is washed to obtain a decomposed aluminum hydroxide. The average particle size d of the decomposed aluminum hydroxide 50 =25.6 μm; the decomposition rate of...

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Abstract

The invention discloses a method for preparing sand-shaped aluminum oxide. The method for preparing the sand-shaped aluminum oxide includes steps that 1) using supersaturated sodium aluminate solution as decomposition stock solution, and adding seed crystal to perform primary seed precipitation to obtain primary seed precipitation mother liquor and primarily decomposed aluminum hydroxide; 2) taking the primarily decomposed aluminum hydroxide and sodium aluminate solution to perform secondary seed precipitation to obtain secondary seed precipitation mother liquor and boehmite; 3) washing the boehmite and roasting to obtain the sand-shaped aluminum oxide. The sand-shaped aluminum oxide prepared by the method is featured with high decomposition rate, less impurity content, high product quality and the like, and meanwhile, the alpha-Al2O3 in the product is less, and the aluminum electrolysis is facilitated.

Description

technical field [0001] The invention relates to a method for preparing sandy alumina, which belongs to the technical field of aluminum metallurgy. Background technique [0002] Sandy alumina is the raw material for modern aluminum electrolysis, and the average particle size of the product is required to be d 50 Mainly distributed between 60 ~ 80μm, with γ-Al 2 o 3 Main phase, α-Al 2 o 3 Phase is less than 5%. Sand-like alumina is decomposed by supersaturated sodium aluminate solution seed crystals (hereinafter referred to as seeds) to obtain coarse-grained aluminum hydroxide, and then calcined at a temperature of 950-1100 ° C. The technical key lies in the production of qualified aluminum hydroxide with lower impurity content and coarser particle size during the sorting process. [0003] At present, my country's alumina enterprises mainly adopt a one-stage seed separation process, that is, adding a large amount of aluminum hydroxide seeds to the first tank, and then co...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/14
Inventor 刘桂华李小斌齐天贵张闻彭志宏周秋生
Owner CENT SOUTH UNIV
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