Process method for recovering tungsten from honeycomb type SCR waste catalyst

Abstract

The invention relates to a process method for recovering tungsten from a honeycomb type SCR waste catalyst. The waste catalyst is crushed, dust and impurities are washed away by adding water, the waste catalyst is dried and ground into powder and then subjected to high-temperature leaching under pressure, filter residues and a leaching solution are obtained through soil-liquid separation, the filter residues are washed with deionized water, sodium, tungsten and vanadium in the filter residues are washed away, and washing water is recovered; after impurities in the leaching solution are removed, hydrochloric acid is added to the leaching solution and the washing water so as to adjust the pH value, then the leaching solution and the washing water are fed into ion exchange equipment, and a mixed solution containing ammonium paratungstate and ammonium metavanadate is obtained through the ion exchange and desorption procedures; after the pH value of the mixed solution is adjusted, ammonium salt is added, the temperature is adjusted, solid-liquid separation is conducted after precipitation crystallization, filtrate is collected, and the filtrate is evaporated and crystallized to obtain ammonium paratungstate crystal. According to the process method for recovering the tungsten from the honeycomb type SCR waste catalyst, resourceful treatment of the waste catalyst is achieved, environmental pollution is reduced, the recovery rate of the ammonium paratungstate is high, the quality of recovered products is good, neither high temperature nor high pressure is needed, energy consumption is low, cost is low, waste water is reused or discharged after meeting the standard, the environmental risk is small, and the method has high practicality.

Description

technical field [0001] The invention relates to the field of catalyst recovery, in particular to a recovery process of SCR waste catalysts, and in particular to a process method for recovering tungsten from honeycomb-type SCR waste catalysts. Background technique [0002] The selective catalytic reduction (SCR) flue gas denitration process has been widely used in the reduction of nitrogen oxides in thermal power plants in my country. At present, more than 90% of the nitrogen oxides reduction at home and abroad adopts the SCR flue gas denitration process. The denitration catalyst is an important raw material for the SCR flue gas denitration process, mainly composed of titanium dioxide (TiO2). 2 , content 80%-90%), vanadium pentoxide (V 2 O 5 , content 1%-5%), tungsten trioxide (WO 3 , content 5%-10%) composition. While the nitrogen oxide emission is greatly reduced, a large amount of waste flue gas denitration catalysts containing toxic and harmful substances are produced...

AI Technical Summary

Problems solved by technology

If the recycling and harmless treatment cannot be carried out properly, it will easily cause environmental pollution

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