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Method for recycling acid in process of producing alumina from fly ash by acid method

A technology for fly ash and alumina, which is applied in the removal of alumina/aluminum hydroxide, chlorine/hydrogen chloride, solid waste, etc., achieves the effects of simple process, low production cost, and easy control of the production process

Inactive Publication Date: 2010-10-20
CHINA SHENHUA ENERGY CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

None of the above patents has carried out further experimental research on acid recovery, just a brief introduction

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  • Method for recycling acid in process of producing alumina from fly ash by acid method

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Take the fluidized bed fly ash and crush it to 150 mesh, add water to make a slurry with a solid content of 30wt%, magnetically separate it on a vertical ring magnetic separator with a magnetic separation field strength of 15,000 Gs, and magnetically separate it three times until the pulverized coal The content of iron oxide in the ash is 0.8wt%. After pressing with a basket filter press, a filter cake with a solid content of 34.5 wt% was obtained. Put the filter cake into an acid-resistant reactor, add 22wt% hydrochloric acid for acid dissolution, the molar ratio of HCl in hydrochloric acid to alumina in ash is 5:1, the reaction temperature is 150°C, the reaction time is 2 hours, and the reaction pressure is 1.0 MPa. The aluminum chloride solution obtained by acid dissolution is passed into a resin column to remove iron. The resin column is in a single column mode. The resin used is D001 (Anhui Wandong Chemical Plant), the treatment temperature is 60 ° C, and the flow ...

Embodiment 2

[0028] The main process conditions for preparing metallurgical grade alumina with circulating fluidized bed ash are the same as in Example 1. Wherein the acid dissolution step adds hydrochloric acid concentration to be 26.5wt%.

[0029] The hydrogen chloride gas produced by calcination is cooled to 90°C through the cooling tower, and then enters the acid absorption tower, and the water injection speed in the acid absorption tower is controlled to 120L / min for preliminary acid gas recovery. The acid gas not fully absorbed in the absorption tower is introduced into the vacuum circulation acid storage tank, and its vacuum degree is controlled at -0.07KPa for secondary recovery of hydrochloric acid. The acid absorption liquid was weighed and chemically analyzed to obtain a concentration of hydrochloric acid of 26.9 wt%, and a recovery rate of hydrogen chloride of 99.75%. Finally, release the absorption acid in the absorption tower and acid storage tank, add water to adjust its co...

Embodiment 3

[0031] The main process conditions for preparing alumina from circulating fluidized bed ash are the same as in Example 1, wherein the concentration of hydrochloric acid added in the acid dissolution step is 30 wt%.

[0032] The hydrogen chloride gas produced by calcination is cooled to 94°C through the cooling tower, and enters the acid absorption tower. The water injection speed in the acid absorption tower is controlled to 110L / min for preliminary acid gas recovery. The acid gas not completely absorbed in the absorption tower is introduced into the vacuum circulation acid storage tank, and its vacuum degree is controlled at -0.06KPa for secondary recovery of hydrochloric acid. The acid absorption liquid was weighed and chemically analyzed to obtain a concentration of hydrochloric acid of 25.4 wt%, and a recovery rate of hydrogen chloride of 99.69%. Finally, release the absorption acid in the absorption tower and acid storage tank, add hydrochloric acid with a concentration o...

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Abstract

The invention relates to a method for recycling acid in the process of producing alumina from fly ash by an acid method. The method comprises the following steps of magnetic separation and iron removal of the fly ash, acid dissolution, resin adsorption and iron removal, condensation crystallization, calcination, cooling, primary recycle of hydrogen chloride gas, secondary recycle of hydrogen chloride gas, regulation of concentration of recycled hydrochloric acid and application of the obtained hydrochloric acid to the step of acid dissolution. The method has the advantages of simple process, easily controlled production process, low production cost and recyclable adsorbed hydrogen chloride product.

Description

technical field [0001] The invention relates to a method for recycling acid in the process of producing alumina by fly ash acid method. Background technique [0002] my country is a large coal-producing country, and coal is used as the basic fuel for electric power production. The steady development of the energy industry in recent years has brought about a sharp increase in the discharge of fly ash, which has caused enormous pressure on my country's national economic construction and ecological environment. Because fly ash contains useful mineral resources such as alumina, comprehensive utilization of fly ash powder and turning waste into treasure has become a widespread research hotspot. Among the methods for extracting alumina from fly ash, the acid method or acid-base combined method is being widely used because of its high dissolution rate and simple process for extracting alumina. Among them, the research on the recycling of hydrochloric acid produced in the process ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01B7/01B09B3/00
Inventor 于德胜郭昭华魏存弟蒋引珊池君洲王永旺
Owner CHINA SHENHUA ENERGY CO LTD
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