Technological method for producing high-purity low-iron aluminum sulfate by using coal ash and comprehensively utilizing coal ash

Abstract

The invention discloses a technological method for producing high-purity low-iron 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, organic alcohol alcoholization for acid rinse, organic alcohol alcoholization for deferrization and aluminum sulfate dewatering and drying on the coal ash to obtain the high-purity low-iron aluminum sulfate with low Fe content. The invention solves the problems on impurity removal and purification of the aluminum sulfate in the recycling process of the coal ash, simplifies the process flow, reduces the energy consumption, solves the technical problem of overlarge accumulation of secondary residue quantity, achieves high extraction ratio of aluminum contained in the coal ash, and realizes the recycling of organic alcohol and sulfuric acid and the comprehensive utilization of 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. The technological method has the advantages of simple process, short flow, easiness for control of aproduction process, high aluminum extraction ratio, low impurity content of products and stable quality.

Description

technical field [0001] The invention relates to resource utilization and comprehensive utilization of fly ash, in particular to a process for producing high-purity and low-iron 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. It mainly comes from by-products of coal-fired power plants. For every ton of coal burned, 230kg of fly ash will be produced. It is estimated that by 2020, the national fly ash accumulation will reach 5-6 billion tons. The massive accumulation of fly ash not only occupies a large amount of land resources, but also causes serious pollution to air, water and soil. The traditional way to deal with fly ash is landfill, which cannot fundamentally solve the pollution caused by fly ash to the environment, and also greatly wastes this useful secondary resource. In terms of chemical composition, fly ash is a medium-grade aluminum ore ric...

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

200810011311.2 discloses a method for preparing aluminum sulfate using 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, converting into aluminum sulfate solution, evaporation Concentrate, cool and crystallize 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. The obtained aluminum sulfate crystals contain more impurities and are difficult to obtain. Preparation of high-purity low-iron aluminum sulfate products, limited popularization and application

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