Method for extracting tungsten, titanium and vanadium from waste SCR (selective catalytic reduction) catalyst

Abstract

The invention discloses a method for extracting tungsten, titanium and vanadium from a waste SCR (selective catalytic reduction) catalyst, which comprises the following steps: crushing the waste SCR catalyst, adding a strongly alkaline solution, and reacting; filtering, separating, then adding strong acid into the sodium tungstate and sodium vanadate mixed solution, and reacting to obtain tungstic acid and a sodium salt and vanadic acid mixed solution; regulating the pH value of the sodium salt and vanadic acid mixed solution until precipitate is separated out, thus obtaining ammonium vanadate; then adding sulfuric acid into the tungsten-and-vanadium-removed SCR catalyst, and reacting to obtain a titanyl sulfate solution and solids such as aluminum slag and the like; then adding water into the titanyl sulfate solution, and hydrolyzing to obtain titanic acid and a waste acid solution; and finally, respectively calcining the obtained ammonium vanadate, tungstic acid and titanic acid to obtain vanadium pentoxide, tungsten trioxide and titanium dioxide. According to the invention, tungsten, titanium and vanadium can be extracted from the SCR catalyst through the reaction with strong alkali and strong acid at a low temperature, the equipment requirement is low, the energy consumption is low, some products having added values can be coproduced, and no secondary pollution is generated, thereby facilitating popularization and application.

Description

technical field [0001] The invention belongs to the technical field of recycling waste catalysts, in particular to a method for extracting tungsten, titanium and vanadium from waste SCR catalysts. Background technique [0002] SCR (Selective Catalytic Reduction) catalyst is used in thermal power plants to remove nitrogen oxide pollutants produced by combustion, which also contains V 2 o 5 and other harmful substances. According to data, as of 2008, SCR devices of 20 million kilowatts of thermal power units have been put into operation in China, and the installed capacity of SCR devices under construction in 2009 is 100 million kilowatts. The resulting problem of SCR catalyst recycling and reuse Also on the agenda. It is estimated that by 2010, the installed capacity of domestic SCR devices will reach 320 million kilowatts, and the initial filling capacity of catalysts will reach 260,000 m 3 . Calculated based on the three-year service life of the SCR catalyst, by 2012, ...

AI Technical Summary

Problems solved by technology

Because this method needs to be roasted at high temperature for many times, the equipment requirements are high, the investment is large, the energy consumption is high, and this method needs to use excessive sodium carbonate, which will produce a large amount of carbon dioxide gas and cause serious pollution to the environment.