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Desiliconizing additive for producing aluminum oxide in alkali process and preparation method thereof

An additive and alumina technology, applied in the preparation of alkali metal aluminate/alumina/aluminum hydroxide, purification of aluminate/alumina/aluminum hydroxide, etc., can solve the problem of removing silica and difficult to handle low Grade bauxite resources, loss of aluminum and sodium, etc.

Inactive Publication Date: 2012-06-27
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the above production process, a certain amount of silicon dioxide will enter the solution system as a harmful substance; in the existing industry, processes such as dissolution desilication, medium pressure desilication, and additive deep desilication are generally used; Calcium, red mud, calcium aluminate, calcium aluminum carbonate, etc. are used as desiliconization additives; usually, the aluminum-silicon ratio of the obtained desiliconization product is 2.0, and the sodium-silicon ratio is about 1.3, resulting in a great loss of aluminum and sodium ; so it is difficult to deal with low-grade bauxite resources; and the existing desiliconization additives cannot effectively remove silica under the condition that the concentration of sodium oxide is higher than 300g / L; Silicon, while reducing the loss of sodium and aluminum, and improving the range of bauxite available in the alkaline production of alumina process, is one of the most important issues that people pay attention to in the process of alkaline production of alumina using bauxite as raw material

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1) Dissolve a certain amount of ferric chloride in water, add a theoretical amount of sodium hydroxide and precipitate completely to obtain ferric hydroxide;

[0023] 2) Combine the prepared ferric hydroxide with calcium oxide and sodium carbonate according to the hydrated calcium salt 3CaO·Fe 2 o 3 ·CaCO 3 12H 2 The theoretical molar ratio of O is mixed, and water is added to make the liquid-solid weight ratio in the reaction solution 15:1. At a reaction temperature of 25° C. and a reaction time of 10 hours, the desiliconization compound for the production of alumina by the alkaline method of this embodiment is obtained. Additive (calcium ferrite hydrate, its molecular formula is 3CaO·Fe 2 o 3 ·CaCO 3 12H 2 O).

[0024] The desiliconization additive (calcium ferrite hydrate) of the present embodiment is used for the desilication of the production of alumina by alkaline method:

[0025] In the silicon-containing solution of Alkali production of alumina that need...

Embodiment 2

[0027] 1) Dissolve a certain amount of ferric chloride in water, add a theoretical amount of sodium hydroxide and precipitate completely to obtain ferric hydroxide;

[0028] 2) Combine the prepared ferric hydroxide with calcium oxide and calcium sulfate according to the hydrated calcium salt 3CaO·Fe 2 o 3 ·CaSO 4 12H 2 The theoretical molar ratio of O is mixed, and water is added to make the liquid-solid weight ratio in the reaction solution 15:1. At a reaction temperature of 80° C. and a reaction time of 12 hours, the desiliconization compound for the production of alumina by the alkaline method of this embodiment is obtained. Additives (calcium sulfoferrate hydrate, whose molecular formula is 3CaO Fe 2 o 3 ·CaSO 4 12H 2 O)

[0029] The desiliconization additive (calcium thioferrate hydrate) of the present embodiment is used for the desilication of alumina produced by alkaline process:

[0030] In the silicon-containing solution of Alkali production of alumina that ne...

Embodiment 3

[0032] 1) Dissolve a certain amount of ferrous chloride in water, add a theoretical amount of sodium hydroxide and precipitate completely to obtain ferric hydroxide;

[0033] 2) Combine the prepared ferric hydroxide with calcium oxide and sodium carbonate according to the hydrated calcium salt 3CaO·Fe 2 o 3 ·CaCO 3 12H 2 The theoretical molar ratio of O is mixed, and water is added to make the liquid-solid weight ratio in the reaction solution 20:1. At a reaction temperature of 30° C. and a reaction time of 14 hours, the desiliconization compound for the production of alumina by the alkaline method of this embodiment is obtained. Additive (calcium carbon ferrate hydrate).

[0034] The desiliconization additive (calcium ferrite hydrate) of the present embodiment is used for the desilication of alkaline production of alumina:

[0035] In the silicon-containing solution of Alkali production of alumina that needs to be desiliconized: the concentration of sodium oxide is 200g / L...

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Abstract

The invention relates to a desiliconizing additive for producing aluminum oxide in an alkali process. The molecular formula of the desiliconizing additive is 3CaO Fe2O3 CaR 12H2O in which R is SO4<2->. The preparation method of the desiliconizing additive comprises the following steps of: (1) reacting iron salt as a raw material with sodium hydroxide or potassium hydroxide as a precipitant to prepare ferric hydroxide, wherein the iron salt is ferric chloride, ferrous chloride, ferric nitrate, ferrous nitrate, ferric sulfate or ferrous sulfate; (2) mixing and reacting the ferric hydroxide prepared in the step (1) with calcium oxide and calcium sulfate in the theoretical molar ratio of hydrated calcium salt 3CaO Fe2O3 CaR 12H2O when R is SO4<2->, maintaining a liquid-solid weight ratio at (10-40):1, a reaction temperature at 20-100 DEG C and reaction time for 10-20 hours, and finally, preparing the desiliconizing additive for producing aluminum oxide in the alkali process. The desiliconizing additive disclosed by the invention can effectively realize removal of silicon dioxide in an alkaline medium.

Description

[0001] The patent application of the present invention is a divisional application filed on November 2, 2007 with the application number 200710176781.X and the title of the invention "Desiliconization Additive for Alkali Production of Alumina and Its Preparation Method". technical field [0002] The invention relates to a desiliconization additive and a preparation method thereof, in particular to a method for effectively reducing the concentration of silicon dioxide in the solution and reducing the content of sodium and aluminum in the desiliconization product during the production of alumina using bauxite as a raw material by the alkaline method A desilication additive for the production of alumina by an alkaline process, a preparation method and use thereof. Background technique [0003] Alkaline production of alumina is to use alkali (sodium hydroxide or sodium carbonate) to treat bauxite ore, so that the alumina in the ore is converted into sodium aluminate solution; imp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/06C01F7/46
Inventor 洪涛郑诗礼张懿
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI