Bayer process dissolving-out method

A Bayer process, sodium ferrite technology, applied in carbon capture, alumina/aluminum hydroxide, cement production, etc., can solve problems such as increased energy consumption, complex process, alkali loss, etc., to achieve short firing time and process flow. Simple, high recovery effect

Inactive Publication Date: 2008-02-06
GUIZHOU BRANCH CHINA ALUMINUM IND
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AI Technical Summary

Problems solved by technology

If this part of the alkali in the red mud is not recycled, it will cause a large amount of alkali loss. If it is recycled, it needs to be processed by

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0014] 1. Preparation of Sodium Ferrite

[0015] Dilute sodium carbonate and iron ore by Na 2 O / Fe 2 o 3 (Na 2 O and Fe 2 o 3 Molecular ratio) is calculated at a ratio of 1:1, mix well, control the sintering temperature in the sintering furnace at 800-1100°C, and the sintering time is 10-60 minutes, and obtain sodium ferrite for later use.

[0016] 2. Pretreatment and dissolution of bauxite

[0017] Alkaline concentration N during pretreatment k 100~450g / L, add sodium ferrite Na according to a certain ratio 2 O Fe 2 o 3 , lime CaO and bauxite, the solid content is 50-300g / L, the amount of sodium ferrite and lime added is based on the silicon in the bauxite to generate iron hydrated garnet (3CaO·Fe 2 o 3 · nSiO2 2 ·(6-2n)H 2 O) to calculate, where the coefficient n is 1 to 2.5. Pretreatment at a temperature of 80-180°C for 0.5-12 hours, after pretreatment, the slurry is subjected to liquid-solid separation, and the solid is eluted under conventional Bayer process ...

Embodiment 1

[0021] Dilute sodium carbonate and iron ore by Na 2 O and Fe 2 o 3 The molecular ratio is 1 to 1, and the sintering temperature is controlled at 1000°C in the sintering furnace, and the sintering time is 30 minutes to obtain sodium ferrite; k Under the condition of 450g / L, sodium ferrite, lime and bauxite are added according to the solid content of 80g / L. 2 o 3 · nSiO2 2 ·(6-2n)H 2 The coefficient in O is n=2.0, the reaction temperature is 90°C, and the reaction time is 12 hours. After the treatment, liquid-solid separation is carried out, and a certain amount of mother liquor for dissolution is added to the solid, and the dissolution is carried out at a temperature of 260°C for 45 minutes. The aluminum-silicon ratio of the dissolved red mud is 0.73, and the sodium-silicon ratio is 0.21.

Embodiment 2

[0023] Dilute sodium carbonate and iron ore by Na 2 O and Fe 2 o 3 The molecular ratio is 1 to 1, and the sintering temperature is controlled at 900°C in the sintering furnace, and the sintering time is 30 minutes to obtain sodium ferrite; k Under the condition of 300g / L, add sodium ferrite, lime and bauxite according to the solid content of 150g / L. 2 o 3 · nSiO2 2 ·(6-2n)H 2 The coefficient in O is n=2.0, the reaction temperature is 100°C, and the reaction time is 8 hours. After the treatment, liquid-solid separation is carried out, and a certain amount of stripping liquid is added to the solid, and the stripping is carried out at a temperature of 260°C for 45 minutes. The aluminum-silicon ratio of the dissolved red mud is 0.71, and the sodium-silicon ratio is 0.19.

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Abstract

The invention provides a dissolving method with Bayer process, relating to a preparation method used in the dissolving process, in which diasporic bauxite is used as a raw material and aluminum oxide is produced with Bayer process. The invention is characterized in that: in the dissolving process, sodium ferrate, lime and the lye is added into bauxite, the amount of sodium ferrate and lime is calculated according to silicon content in bauxite which can be completely changed into molten iron garnet(3CaO.Fe2O3.nSiO2.(6-2n)H2O); the lye concentration NK is 100g/L to 450g/L, aluminium oxide concentration is less than 5g/L, the solid content of the dissolved preparation ore pulp is 50g/L to 300g/L, the temperature is 80 DEG C to 180 DEG C the dissolving time is 0.5 hour to 12 hours., and then the solid and the liquid are separated, the solid is dissolved in the condition of the conventional Bayer process. Through the invention, the existing form of silicate mineral of the dissolved red mud is mainly molten iron garnet instead of the usual sodium-silicon residue. The invention reduces the alumina-silicon ratio A/S and the sodium-silicon ratio N/S of the dissolved red mud. The invention is adapted to process diasporic bauxite source of Chinese high alumina-silicon.

Description

technical field [0001] The invention relates to a Bayer process stripping method, which relates to a pretreatment method in the stripping process of producing alumina by Bayer process using diaspore type bauxite as raw material. technical background [0002] In the Bayer dissolution process of processing diaspore type bauxite, lime is usually added as a dissolution additive at 5% to 8% of the dry ore amount. The addition of lime can increase the dissolution rate of alumina and reduce alkali consumption. , but usually, the aluminum-silicon ratio A / S of the dissolved red mud is 1.3-2.0, and the sodium-silicon ratio N / S is about 0.5. If this part of the alkali in the red mud is not recycled, it will cause a large loss of alkali. If it is recycled, it needs to be processed by sintering method with high energy consumption, which will increase the energy consumption of the whole production process and complicate the process. Contents of the invention [0003] The purpose of the...

Claims

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Application Information

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IPC IPC(8): C01F7/02C04B7/32
CPCY02P40/18
Inventor 李新华尹中林武国宝
Owner GUIZHOU BRANCH CHINA ALUMINUM IND
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