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Purification method for middle-low bauxite

A low-grade bauxite and bauxite technology, applied in chemical instruments and methods, aluminum compounds, alkaline earth metal silicates, etc., can solve the problems of inability to improve the ore aluminum-silicon ratio, low energy consumption, etc. Mild conditions, high desulfurization efficiency, and the effect of improving the ratio of aluminum to silicon

Pending Publication Date: 2018-11-02
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

During the roasting and cooling process, the cyclone separator is used for multi-stage heat exchange, and the heat is recovered to preheat the ore. The energy consumption is low, but the aluminum-silicon ratio of the ore cannot be increased.

Method used

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  • Purification method for middle-low bauxite
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  • Purification method for middle-low bauxite

Examples

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Embodiment 1

[0078] In this embodiment, the medium and low-grade bauxite in a place in Henan is used as raw material to remove impurities by the method for removing impurities of medium and low-grade bauxite according to the present invention. The composition of the bauxite (mass percentage, wt%, the same below) )As shown in Table 1.

[0079] Table 1

[0080]

[0081] The specific impurity removal process is as figure 1 shown, including the following steps:

[0082](1) Grind the bauxite, pass through a 100-mesh sieve to 80%, send it into a fluidized roaster after preheating and roast it at 950°C for 10 minutes, and feed a sufficient amount of air during the roasting process to obtain roasted bauxite Bauxite, wherein the mass fraction of S is 0.01wt%, and the desulfurization rate is 89%; the mass fraction of C is 0.1wt%, and the decarburization rate is 67%; the sulfur-containing flue gas generated during the roasting process is passed into the milk of lime reaction, and then carry out...

Embodiment 2

[0086] In this embodiment, the medium and low-grade bauxite in a place in Henan is used as raw material to remove impurities by the method for removing impurities of medium and low-grade bauxite according to the present invention. The composition of the bauxite (mass percentage, wt%, the same below) )As shown in table 2.

[0087] Table 2

[0088]

[0089] The specific impurity removal process includes the following steps:

[0090] (1) Grind the bauxite to 73% and pass through a 100-mesh sieve. After preheating, it is sent to a fluidized roaster for roasting at 1000° C. for 5 minutes. During the roasting process, a sufficient amount of air is introduced to obtain roasted bauxite. Bauxite, wherein the mass fraction of S is 0.01wt%, and the desulfurization rate is 90%; the mass fraction of C is 0.1wt%, and the decarburization rate is 64%; the sulfur-containing flue gas generated during the roasting process is passed into the milk of lime reaction, and then carry out solid-li...

Embodiment 3

[0094] In this embodiment, the medium and low-grade bauxite in a place in Henan is used as raw material to remove impurities by the method for removing impurities of medium and low-grade bauxite according to the present invention. The composition of the bauxite (mass percentage, wt%, the same below) )as shown in Table 3.

[0095] table 3

[0096]

[0097] The specific impurity removal process includes the following steps:

[0098] (1) Grind the bauxite to 89% and pass through a 100-mesh sieve. After preheating, it is sent to a fluidized roaster for roasting at 1050°C for 30 minutes. During the roasting process, sufficient air is introduced to obtain the roasted bauxite. Bauxite, wherein the mass fraction of S is 0.01wt%, and the desulfurization rate is 96%; the mass fraction of C is 0.1wt%, and the decarburization rate is 75%; the sulfur-containing flue gas generated during the roasting process is passed into the milk of lime reaction, and then carry out solid-liquid sepa...

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Abstract

The invention provides a purification method for middle-low bauxite. The method comprises the following steps: (1),putting bauxite into a fluidization roasting furnace for roasting, and feeding air during roasting, so as to obtain roasted bauxite; (2), mixing the roasted bauxite with alkali liquor for desilicication reaction, and separating solid from liquid to obtain bauxite concentrate and desilicication liquid; and (3), performing desilicication to the desilicication liquid, separating solid from liquid to obtain calcium silicate products and alkali liquor, adjusting the concentration of the alkali liquor and getting back to step (2) for cyclic utilization. According to the invention, silicon, sulphur, carbon and other impurities in middle-low bauxite are removed, so that not only can ore grade be improved, but also resource utilization of refractory ore can be realized; consumption of alkali and lime in dissolution process of aluminium oxide can be reduced; and meanwhile, dischargeof red mud is reduced. The purification method has the advantages that the production cost of aluminium oxide is lowered, solid waste discharge is reduced, the energy consumption during roasting is relatively low, and the method has good economic benefit and is beneficial to environmental protection.

Description

technical field [0001] The invention belongs to the technical field of impurity removal for bauxite, and relates to a method for removing impurities of middle and low grade bauxite, in particular to a method for removing impurities of middle and low grade fluidized roasting. Background technique [0002] my country's bauxite resources are characterized by high aluminum, high silicon and low aluminum-silicon ratio, and ores with an aluminum-silicon ratio below 5 account for more than 70% of the total resources. In recent years, the domestic alumina industry has developed rapidly and consumed a large amount of bauxite. The high-grade bauxite with an aluminum-silicon ratio of more than 7 in my country is on the verge of depletion. Many alumina companies are forced to use low-grade bauxite. There are many impurities in low- and medium-grade bauxite, among which the impurities that have the greatest impact on the production of alumina by Bayer process are mainly silicon, sulfur a...

Claims

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Application Information

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IPC IPC(8): C01F7/06C01B33/24C01F11/46
CPCC01B33/24C01F7/0606C01F11/464C01P2006/80
Inventor 曹绍涛张泽豪陈芳芳张懿
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI