Technological method for producing industrial aluminum sulfate by using coal ash and comprehensively utilizing coal ash

Abstract

The invention discloses a technological method for producing industrial aluminum sulfate by using coal ash and comprehensively utilizing the coal ash, comprising the following steps of: carrying out mechanical activation, flotation decarburization, magnetic separation for deferrization, aluminum extraction with sulfuric acid, solid-liquid separation, concentration of aluminum sulfate crude liquor, aluminum sulfate recrystallization, secondary solid-liquid separation and aluminum sulfate dewatering and drying on the coal ash to obtain the industrial grade aluminum sulfate with the Fe content lower than 0.02 percent. The invention provides a simple impurity-removing purifying method of the aluminum sulfate in the recycling process of the coal ash, which is beneficial to simplification of the process flow, reduction of the energy consumption and solving of the technical problem of overlarge accumulation of secondary residue quantity, has high extraction ratio of aluminum contained in the coal ash, can obtain side products including unburnt black, magnetic iron powder, iron-containing aluminum sulfate crystals, high-silicon-dust active mineral blending materials or novel silicon-magnesium cement, and the like and has the advantages of short process flow, easiness for control of a production process, high aluminum extraction ratio, low production cost, good deferrization effect and stable quality.

Description

technical field [0001] The invention relates to a process method for resource recovery and comprehensive utilization of fly ash, in particular to a process method for producing industrial aluminum sulfate from fly ash and its comprehensive utilization. Background technique [0002] Fly ash is the solid residue left after coal combustion in coal-fired boilers, mainly from coal-fired power plants. At present, the annual accumulation of fly ash in the country has reached 3 billion tons, occupying a large amount of land resources and seriously polluting air and groundwater resources. From the perspective of resources, fly ash is a medium-grade aluminum ore rich in aluminosilicates, and with the continuous depletion of bauxite resources in my country, the use of fly ash to extract aluminum has a very broad application prospect. [0003] Aluminum sulfate extracted from fly ash is mainly used in drinking water, industrial water, wastewater and sewage treatment, papermaking, printi...

AI Technical Summary

Problems solved by technology

However, because the original fly ash did not remove iron, and the acid leaching solution did not take effective iron removal measures, resulting in high impurity components in aluminum sulfate products, the product use is limited

Application number 200810011311.2 discloses a method for preparing aluminum sulfate from fly ash, including the following steps: mechanical activation, sulfuric acid heating and pressure leaching reaction, generation of basic aluminum sulfate, adding sulfuric acid to the basic aluminum sulfate liquid, and converting it into an aluminum sulfate solution , evaporation, concentration, cooling and crystallization to obtain aluminum sulfate crystals. This patent application pursues the goal of increasing the extraction rate of aluminum, which involves the complex process of forming the intermediate basic aluminum sulfate, and the obtained aluminum sulfate crystals contain more impurities. , it is difficult to prepare aluminum sulfate products, and the popularization and application are limited

Images