Method for strengthening dissolution of fly ash

Abstract

The invention provides a method for strengthening dissolution of fly ash. The method comprises the following steps: (1) mixing white mud and excessive hydrochloric acid, carrying out dissolution reaction, and carrying out solid-liquid separation; (2) mixing the first solid-liquid separation overflow obtained in the step (1) with fly ash, carrying out a dissolution reaction, and carrying out solid-liquid separation; (3) filtering the second solid-liquid separation underflow obtained in the step (2) to obtain white mud; and (4) recycling the white mud obtained in the step (3) for the step (1). The method further comprises a pre-dissolution process, and the pre-dissolution process comprises the following steps: a, mixing the fly ash and hydrochloric acid, carrying out a pre-dissolution reaction, and carrying out solid-liquid separation; b, filtering the third solid-liquid separation underflow obtained in the step a to obtain white mud; c, returning the white mud obtained in the step b tothe step (1), and then stopping the pre-dissolution procedure; wherein after the pre-dissolution process is stopped, the white mud in the step (1) comes from the step (3). According to the method, thedissolution temperature of active aluminum in the fly ash can be reduced, and the dissolution time is shortened.

Description

technical field [0001] The invention belongs to the field of comprehensive utilization of fly ash, in particular to a method for enhanced dissolution of fly ash. Background technique [0002] my country is a big energy consumption country. With the rapid development of the national economy, the demand for energy is increasing day by day. In the structure of primary energy production and consumption in my country, the proportion of coal has been maintained at about 70%. The discharge of solid waste fly ash after coal combustion has increased sharply, which has caused certain impacts on the ecological environment. [0003] The Ordos Zhungeer area of ​​Inner Mongolia is rich in coal resources, and the coal is accompanied by abundant non-ferrous metals such as aluminum, gallium, and lithium. After the mined coal is burned by the boiler of the power plant, a large amount of alumina and gallium are enriched in the obtained fly ash. The content of alumina is usually above 50wt%, ...

AI Technical Summary

Problems solved by technology

[0006] The aforementioned two-stage dissolution process has the following problems: after the first stage of dissolution, most of the active substances in the fly ash have reacted, causing the acidity in the pulp to decrease during the second stage of dissolution, making the low active substances in the fly ash very Difficult to react with low-concentration hydrochloric acid, resulting in higher dissolution temperature (about 160°C) and longer time

Images