Method for extracting alumina from coal ash

A fly ash and aluminum hydroxide technology, which is applied in the fields of alumina/aluminum hydroxide, solid waste removal, waste treatment, etc., can solve the problems that silicon and aluminum cannot be separated directly, poor quality of alumina, high sintering temperature, etc. To achieve the effect of alleviating the shortage of resources, low loss rate and low sintering temperature

Active Publication Date: 2011-09-14
北京蔚然欣科技有限公司
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Problems solved by technology

In this way, it not only solves the problem of high sintering temperature and Al 2 o 3 The key problems such as low extraction rate, inability to directly separate silicon and aluminum, and poor quality of alumina have overcome the Bayer process’s strict requirements on the aluminum-silicon ratio (A / S) and ore mineral types, and at the same time achieved low sintering temperature, Short sintering time, can effectively control the activation ratio of aluminum and silicon

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  • Method for extracting alumina from coal ash
  • Method for extracting alumina from coal ash

Examples

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Effect test

Embodiment 1

[0034] (1) Mix the fly ash of the pulverized coal furnace and the solid sodium carbonate at a ratio of 1:0.6 and grind them into a 100-mesh mixed material.

[0035] (2) Calcining the mixed material obtained in step (1) at a temperature of 620° C. for 60 minutes to obtain roasted clinker. The roasted clinker is divided into several equal parts with the same quality for later use; during roasting, the roasting equipment is connected to the gas output pipe and connected to the carbon separation tank, and the recovered carbon dioxide gas is directly used for carbon separation.

[0036] (3) Add an appropriate amount of water to the first portion of roasted clinker, and make the solid-liquid mass ratio 1:6, and leaching for 50 minutes at a temperature of 10°C. After leaching, filter to obtain filter residue and filtrate respectively. After determination, the leaching rate of alumina in the filtrate is 70%, and the leaching rates of other components such as silicon dioxide and iron ...

Embodiment 2

[0044] (1) Mix the fly ash of the pulverized coal furnace and the solid sodium carbonate at a ratio of 1:2.5 and grind them into a 250-mesh mixed material.

[0045] (2) Calcining the mixed material obtained in step (1) at a temperature of 990° C. for 10 minutes to obtain roasted clinker. The roasted clinker is divided into several equal parts with the same quality for later use; during roasting, the roasting equipment is connected to the gas output pipe and connected to the carbon separation tank, and the recovered carbon dioxide gas is directly used for carbon separation.

[0046] (3) Add an appropriate amount of water to the first portion of roasted clinker, and make the solid-to-liquid mass ratio 1:120, and leaching at 85° C. for 5 minutes. After leaching, filter to obtain filter residue and filtrate respectively. After determination, the leaching rate of alumina in the filtrate is 75%, and the leaching rates of other components such as silicon dioxide and iron oxide are a...

Embodiment 3

[0054] (1) Mix the fly ash of the pulverized coal furnace and the solid sodium carbonate at a ratio of 1:2.3 and grind them into a 150-mesh mixed material.

[0055] (2) Calcining the mixed material obtained in step (1) at a temperature of 720° C. for 50 minutes to obtain calcined clinker. The roasted clinker is divided into several equal parts with the same quality for later use; during roasting, the roasting equipment is connected to the gas output pipe and connected to the carbon separation tank, and the recovered carbon dioxide gas is directly used for carbon separation.

[0056] (3) Add appropriate amount of water to the first batch of roasted clinker, and make the solid-liquid mass ratio 1:15, and leaching for 40 minutes under the temperature condition of 20°C. After leaching, filter to obtain filter residue and filtrate respectively. After determination, the leaching rate of alumina in the filtrate was 79%, and the leaching rates of other components such as silicon diox...

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Abstract

The invention discloses a method for extracting alumina from coal ash. The method comprises the following steps: mixing the coal ash with sodium carbonate in a certain proportion and then grinding; and then extracting the high-pure alumina from the coal ash through the steps such as roasting, circular leaching, precipitation and filtration, carbonating, carbon dioxide and auxiliary recovery, washing, calcination and the like. Compared with the other methods for extracting the alumina from the coal ash, the method in the invention has the advantages of high aluminum hydroxide extraction rate, small residue, low energy consumption, simple and direct technology process, low cost, recoverable and recyclable CO2 and used auxiliary raw material and the like, thereby breaking through the bottleneck of complicated technology and high cost in the existing process for extracting the alumina from the coal ash and creating a new way for development and utilization of high added value of the coal ash.

Description

Technical field: [0001] The invention belongs to the technical field of comprehensive utilization of solid waste discharged in the comprehensive production process of power generation, metallurgy and chemical industry, and particularly relates to a method for extracting alumina from fly ash. Background technique: [0002] In recent years, the rapid development of my country's coal power industry has brought about a sharp increase in the discharge of solid waste fly ash. The total amount of fly ash discharged by coal-fired power plants has increased year by year. In 1995, the discharge of fly ash reached 125 million tons, about 150 million tons in 2000, and by 2009, China's fly ash output reached 375 million tons, equivalent to more than twice the total amount of urban domestic waste in China that year. Because fly ash pollutes the environment in various forms, its massive discharge has caused enormous pressure on my country's national economic construction and ecological envi...

Claims

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Application Information

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IPC IPC(8): C01F7/02B09B3/00
CPCY02W30/20
Inventor 潘爱芳马昱昭马润勇
Owner 北京蔚然欣科技有限公司
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