Fume wet-type magnesia desulfated waste-liquid recovery method

Abstract

The invention relates to the field of the fume wet-type magnesia desulfated waste-liquid recovery of boilers and sinter machines, and the like, in particular to a fume wet-type magnesia desulfated waste-liquid recovery method which adopts flash-evaporating concentration for processing a magnesium sulfate solution, the steps are as follows: the first-effect concentrating step of the magnesium solution, using positive-pressure operation and using fresh vapor as a heat resource, and concentrating the magnesium sulfate solution to 20 percent to 25 percent; the second-effect step of the magnesium sulfate solution, heating the solution by using secondary vapor generated in the first-effect evaporation until the concentration of the magnesium sulfate solution reaches 30 percent to 35 percent; the triple-effect concentrating step of the magnesium solution, heating by triple vapor generated in the second-effect concentrating step by adopting an atmosphere condenser and an evacuator so that the triple-effect concentrating step is operated in a vacuum state, and concentrating the magnesium sulfate solution to the set concentration to form a super-saturation solution in the thrice-effect concentrating step of the magnesium solution; the crystallizing step of magnesium sulfate: conveying the super-saturation solution to a crystallizer to enable the magnesium sulfate to form the crystal of magnesium sulfate heptahydrate to be continuously separated out; and the recovery step of the magnesium sulfate heptahydrate. The invention can generate hydrous magnesium sulfate and achieve high recovery rate.

Description

technical field [0001] The invention relates to flue gas desulfurization, in particular to the fields of boiler, sintering machine flue gas wet magnesia desulfurization waste liquid recovery and the like. Background technique [0002] The flue gas of the coal power industry and the flue gas of the sintering machine used in the iron and steel industry have the following characteristics: [0003] Sulfur dioxide is low and unstable. [0004] There are two main ways to deal with flue gas: [0005] (1) Ammonia desulfurization technology [0006] Use liquid ammonia or ammonia water as an absorbent to remove sulfur dioxide in the flue gas of the sintering machine to reduce the emission of sulfur dioxide and dust. The by-product is ammonium sulfate fertilizer. [0007] This method is used in conjunction with the electron beam method and the pulsed corona method, and these two methods are not only expensive, but also difficult to apply to large-scale units because the equipment co...

AI Technical Summary

Problems solved by technology

Most of these methods have a long process, high investment, and unsatisfactory absorption rate. At the same time, due to the reaction of sulfur dioxide and lime, a layer of coating will be formed on the surface, and the utilization rate of the ab