Method for conducting synergistic solidification stabilization on arsenic in desulphurization gypsum by using high temperature of waste incineration fly ash

Abstract

The invention discloses a method for conducting synergistic solidification stabilization on arsenic in desulphurization gypsum by using high temperature of waste incineration fly ash. The method includes the steps of conducting two-time countercurrent rinsing on the waste incineration fly ash according to the solid-to-liquid ratio of 1:(2-6) to obtain wet fly ash, wherein the rinsing time of eachsection is 10-15 min; adding the wet fly ash into the desulphurization gypsum according to the ratio that the dry basis of the wet fly ash accounts for 5-12wt.% of the desulphurization gypsum, fully stirring, then conducting maintenance for at least 3 h, and obtaining a desulphurization-gypsum-mixed wet material doped with the fly ash; placing the desulphurization-gypsum-mixed wet material into agypsum product die, conducting high-temperature calcination for 30-60 min at 600-800 DEG C, and obtaining a calcinated gypsum material product. According to the method, by using the hydration processof the cement base component of the fly ash, solidification stabilization wrapping is conducted on the free arsenic in the gypsum, the arsenic in the desulphurization gypsum is solidified and stabilized, the hypotoxic desulphurization gypsum is prepared, the safety of gypsum-derivative building material products is ensured, and environmental pollution is reduced.

Description

technical field [0001] The invention relates to a method for preparing desulfurized gypsum, in particular to a method for solidifying and stabilizing arsenic in desulfurized gypsum, which is applied in the technical field of gas emission control environmental engineering, and in the technical field of waste recycling and reduction of toxic substances . Background technique [0002] Desulfurization gypsum is also known as flue gas desulfurization gypsum, sulfur gypsum or FGD gypsum. The main component is the same as natural gypsum, calcium sulfate dihydrate CaSO 4 2H 2 O, content ≥ 93%. Desulfurization gypsum is a by-product of the FGD process, a technology that uses lime-limestone to recover sulfur dioxide from coal or oil flue gas. The technology is to grind the lime-limestone into a slurry, so that the SO-containing 2 The flue gas passes through the slurry scrubber to remove SO 2 . Lime slurry and SO 2 The reaction produces calcium sulfate and calcium sulfite, and t...

AI Technical Summary

Problems solved by technology

Among them, washing and pickling not only produces a large amount of heavy metal wastewater, but the fly ash after washing still needs further disposal; solidification and stabilization use a large amount of cement, asphalt and other materials, which increases the storage capacity consumption of landfills; The stability is debatable; during high-temperature sintering, additional viscous substances need to be added to granulate, and there is no relevant standard for sintered granules, so there are problems in whether they can be applied; high-temperature melting products have a better stabilization effect on heavy metals, but the calorific value of fly ash is low, and energy consumption larger