Method for producing industrial activated aluminum oxide from pulverized fuel ash

Abstract

The invention discloses a method for producing industrial activated aluminum oxide from pulverized fuel ash, comprising the following steps: mechanically activating the pulverized fuel ash, floating and removing carbon, magnetically selecting and removing iron, impregnating in sulfuric acid to extract aluminum, separating solid and liquid, condensing rough liquid of aluminum sulfate, re-crystallizing aluminum sulfate, separating solid and liquid for the second time, dehydrating and drying aluminum sulfate, and calcining aluminum sulfate at a high temperature so as to obtain the industrial activated Al2O3 in which the content of Fe2O3 is lower than 0.5%; and the method completely meets the technical requirement of HG / T3927-2007 industrial activated aluminum oxide. The method is simple in technique, short in flow, easy to control production process, high in aluminum oxide extract rate, low in production cost, low in impurity content, and stable in quality.

Description

technical field [0001] The present invention relates to a method for resource utilization and comprehensive utilization of fly ash, in particular to a method for producing industrial activated alumina from fly ash, that is, a certain concentration of sulfuric acid is used to heat and pressurize to leach aluminum sulfate, and after concentration, use The method of recrystallization removes iron and prepares industrial aluminum sulfate with Fe content lower than 0.02%, and aluminum sulfate is directly calcined to obtain industrial active Al with iron oxide content lower than 0.5%. 2 o 3 . Background technique [0002] Fly ash is the solid residue left after coal combustion in coal-fired power plants. In 2007, my country's fly ash emissions reached 2.5 billion tons. It is estimated that by 2020, the national fly ash emissions will reach more than 5 billion tons. The improvement of comprehensive utilization level and utilization rate of fly ash is related to the healthy develo...

AI Technical Summary

Problems solved by technology

Common pickling methods are divided into hydrochloric acid pickling and sulfuric acid pickling. Since hydrogen chloride gas needs to be produced in the production process of hydrochloric acid pickling, the concentration of hydrochloric acid solution made by water absorption is not more than 36%, which requires a lot of extra water consumption. Once the absorption is not complete, hydrogen chloride gas will leak, and hydrochloric acid has a great corrosion effect on metal equipment, thus affecting its popularization and application

Relatively speaking, the sulfuric acid acid leaching method is a relatively ideal method, for example: Chinese invention patent application number 200510048274.9 discloses a method for extracting alumina from fly ash, and 200610048295.5 discloses a method for preparing alumina from fly ash The method for alumina, 200710012997.2 discloses a method for preparing alumina by using fly ash, etc. However, most of these patented methods are used to produce metallurgical grade alumina, and because the obtained intermediate aluminum sulfate has not been purified and removed , but in the follow-up process, the Bayer method with high energy consumption and backward technology is used to purify, that is, the aluminum sulfate crystal is calcined once to obtain the intermediate γ-Al with relatively high impurity content 2 o 3 , and then through alkali dissolution, sorting, filtration, washing, and secondary calcination to obtain Al with relatively low impurity content 2 o 3 , there are disadvantages such as complex process, many process links, large energy consumption and resource consumption, and high production cost, so it is difficult to be popularized and applied