Water washing and heavy metal removing process suitable for steel mill fly ash

Abstract

The invention provides a water washing and heavy metal removing process suitable for steel mill fly ash. The process comprises the following steps: step 1, conveying steel mill fly ash into a slurry mixing tank through a spiral conveyor, and preparing the fly ash into steel mill fly ash slurry; step 2, conveying the prepared steel mill fly ash slurry into a three-stage countercurrent washing poolstep by step through a pressure pump, performing dechlorination through three-stage countercurrent washing extraction, and removing alkali metal salt in the steel mill fly ash slurry to obtain filtrate and desalted fly ash; step 3, conveying the filtrate to a buffer tank through a pump for buffering, then enabling the filtrate to flow into a neutralization and sedimentation tank, and introducing aneutralized mixed liquid into a flocculation tank for flocculation and sedimentation; step 4, passing the precipitated liquid through a precision filter, performing filtering to obtain filter residues and a filtrate, conveying the filtrate into a pH regulating tank, and regulating the pH value of the liquid to be neutral; and step 5, conveying the liquid in the PH tank to a multi-effect evaporation system, and carrying out multi-stage evaporation. The process is used for separating and recycling steel fly ash.

Description

technical field [0001] The invention relates to the field of dedusting ash treatment, in particular to a water washing and heavy metal removal process suitable for dedusting ash in steel mills. Background technique [0002] The air pollutants emitted by industrial enterprises are treated by bag filter and other dust removal equipment. Most of the particulate matter waste gas is collected and the fly ash is related to the collected particulate gas. , generally have good utilization value. Environmental dust removal is set up to reduce environmental dust pollution, such as dust removal for raw material loading and unloading, transshipment, etc. This type of dust removal is environmental dust removal. Generally speaking, environmental dust is collected at room temperature, and the properties of the medium dust do not change much, so it is relatively easy to use and basically has no harm to production. Process dust is the product of high-temperature physical and chemical react...

AI Technical Summary

Problems solved by technology

First, there are many types and quantities of dust removal ash, and the composition is complex and different, so it is difficult to achieve quantitative batching, resulting in a decline in sintering mineralization performance indicators

The second is that the dust removal and mud sintering performance is poor, and the production experience of iron and steel enterprises for many years

Reduced sintering capacity

The third is that the enrichment of K, Na, CLZn and other elements in the flue gas dedusting ash endangers the sintering ironmaking production, resulting in the sintering trolley sticking, the fan blades hang mud, the efficiency of the dust collector is reduced, the smoke pollution is aggravated, and the amount of equipment maintenance is increased. There is no shortage of precedents for blast furnaces to affect the forward movement and service life or even cause accidents due to the enrichment of harmful elements.

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