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A method for recycling middle-leaf filter residue in alumina production

A technology of alumina and filter residue, applied in the direction of alumina/aluminum hydroxide, etc., can solve the problems of loss of alumina, calcium oxide, and increase in the amount of red mud, and achieve the effect of reducing emissions, good economic benefits and environmental benefits

Active Publication Date: 2017-05-17
河南华慧有色工程设计有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most of the leaf filter residue solids are discharged into the red mud at present, losing alumina and calcium oxide, and increasing the amount of red mud at the same time

Method used

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  • A method for recycling middle-leaf filter residue in alumina production

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] In the leaf filtration process of an alumina plant, the separation and sedimentation test of the leaf filter residue slurry was carried out, and the liquid phase N k 164g / l, Al 2 o 3 183.88g / l, α k 1.47, the solid content is 30g / L, and a polyacrylamide polymer additive is added according to the solid content of the leaf filter residue 0.03‰, the sinking speed is fast, and the compression performance is good. The supernatant was clear, and the liquid-solid weight ratio of the underflow after 60 minutes of sedimentation and compression was 2.0; the added polyacrylamide was a prepared polyacrylamide solution with a concentration of 3.46‰.

[0024] Production of hydrated lime milk with a solid content of 150g / l and an effective calcium content of 66%; according to the chemical formula of calcium aluminate 3CaO.Al 2 o 3 .6H 2 O, after dealumination α k Calculate the amount of milk of hydrated lime as 3.3. Under the condition of reaction temperature of 80°C, after react...

Embodiment 2

[0026] In the leaf filtration process of an alumina plant, the separation and sedimentation test of the leaf filter residue slurry was carried out, and the liquid phase N k 164g / l, Al 2 o 3 183.88g / l, α k 1.47, the solid content is 100g / L, and a polyacrylamide polymer additive is added according to the solid content of the leaf filter residue at 0.05‰. The sinking speed is fast and the compression performance is good. It takes 16 seconds for the settled mud layer interface to pass through 450ml-350ml in the 500ml measuring cylinder. The supernatant was clear, and the liquid-solid weight ratio of the underflow after 60 minutes of sedimentation and compression was 3.0; the added polyacrylamide was a prepared polyacrylamide solution with a concentration of 3.46‰.

[0027] Production of hydrated lime milk with a solid content of 211g / l and an effective calcium content of 83.26%; according to the chemical formula of calcium aluminate 3CaO.Al 2 o 3 .6H 2 O, after dealumination ...

Embodiment 3

[0029] In the leaf filtration process of an alumina plant, the separation and sedimentation test of the leaf filter residue slurry was carried out, and the liquid phase N k 170g / l, Al 2 o 3 187.88g / l, α k 1.49, the solid content is 80g / L, a polyacrylamide polymer additive is added according to the solid content of the leaf filter residue 0.08‰, the sinking speed is fast, and the compression performance is good. It takes 11 seconds for the interface of the settled mud layer in the 500ml measuring cylinder to pass through 450ml-350ml, The supernatant was clear, and the liquid-solid weight ratio of the underflow after 60 minutes of sedimentation and compression was 3.0; the added polyacrylamide was a prepared polyacrylamide solution with a concentration of 3.46‰. Without any other additives, there is no sedimentation effect within 30 minutes.

[0030] Production of hydrated lime milk with a solid content of 250g / l and an effective calcium content of 60%; according to the chemi...

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Abstract

The invention provides a recycling method for leaf filter residues in aluminum oxide production and relates to an improvement in an aluminum oxide production method. The recycling method is characterized in that during the recycling process, leaf filter residue slurry is subjected to solid-liquid separation, and separated feed liquid is returned to a coarse liquid tank; after bottom current obtained after solid-liquid separation is subjected to dealuminization and filter pressing, filter liquid is conveyed to a decomposition mother solution or evaporation stock solution tank, and filter cakes are returned to a lime stock bin. According to the recycling method for the leaf filter residues in aluminum oxide production, compounds of aluminum oxide and calcium oxide in the leaf filter residues can be effectively recycled, the compounds become an effective additive of aluminum oxide products and for aluminum oxide dissolved matter, aluminum oxide is recycled, emissions of red mud are reduced, and therefore good economic benefits and environmental benefits are achieved.

Description

technical field [0001] The invention discloses a method for recycling filter residue in alumina production, and relates to an improvement of an alumina production method. Background technique [0002] At present, in the leaf filtration process of crude liquid in alumina production, milk of lime or a part of fly ash are used as filter aids. The leaf filter residue slurry is the mixed slurry of the semen of the recoil filter cloth and the hanging mud on the filter cloth. The leaf filter residue slurry is usually discharged to the filter cake tank, and its solid content is 30‐100g / l. The main components are semen, red mud and alumina Compounds with calcium oxide. [0003] Lime is a dissolution additive in alumina production. The main principle is that lime reacts in sodium aluminate solution to generate calcium aluminate, which eliminates the influence of titanium minerals during the ore dissolution process, transforms part of sodium silicate slag into hydrated garnet and redu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02
CPCC01F7/02
Inventor 樊大林周风江左会敏车洪生张志斌
Owner 河南华慧有色工程设计有限公司