Method for extracting ammonium sulfate from ammonia desulphurization wastewater by oxidation process

Abstract

The invention provides a method for extracting ammonium sulfate from ammonia desulphurization wastewater by an oxidation process, and belongs to the technical field of treatment of desulphurization waste solutions. The method comprises the steps of: carrying out oxidation reaction in a manner of blowing air or oxygen into the ammonia desulphurization wastewater, wherein in the oxidization reaction, ammonium thiosulfate in the desulphurization wastewater is oxidized into ammonium sulfate, ammonium thiocyanate is not oxidized and further maintained in the desulphurization wastewater; and then extracting ammonium sulfate in an evaporation or crystallization manner. The method disclosed by the invention is suitable for treatment of the desulphurization wastewater produced in the air desulfurization and cyanide-removal processes by a catalytic oxidation method. The method is suitable for treatment of waste liquor in the field of the desulfurization process of hydrogen sulfide containing gases such as coke even gas, natural gas, coal bed gas and refinery gas. By using the method disclosed by the invention, ammonium thiosulfate salt in the wastewater can be transformed into ammonia sulfate salt, ammonium thiocyanate is protected, and the ammonium thiosulfate salt and the ammonium thiocyanate can be separated from the wastewater and purified to obtain the products.

Description

technical field [0001] The invention belongs to the technical field of desulfurization waste liquid treatment, in particular to a method for extracting ammonium sulfate from ammonia desulfurization waste liquid by oxidation. Background technique [0002] The catalytic oxidation desulfurization process using ammonia as the alkali source will inevitably produce desulfurization waste liquid. For a long time, the domestic desulfurization process has no supporting design, and most of the waste liquid produced is consumed by remixing coking coal or being used for wet coke quenching. Coke equipment corrosion, gas desulfurization costs increase, and gas system equipment corrosion rate rises. The existing waste liquid treatment devices basically adopt fractional crystallization physical process, which is not easy to extract high-purity qualified products at one time. The reason is that there are many sulfur compounds and salts in the waste liquid. Ammonium sulfate, ammonium thiosul...

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Problems solved by technology

The oxidation efficiency of the Herohax process is very high, and useful products can be obtained, which can increase the yield of ammonium sulfate. However, this process method requires the equipment to be made of titanium alloy stainless steel corrosion-resistant materials. Due to the high cost of materials and expensive construction costs , the maintenance cost of equipment is also expensive, so this technology has been introduced into China for nearly 30 years, but it has not been accepted by domestic coking manufacturers so far. Another shortcoming of Xirohax waste liquid treatment technology is the precious ammonium thiocyanate resource was destroyed, producing a product of low value-added ammonium sulphate

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