Method for recovering tungsten from waste SCR catalyst regeneration waste alkali liquor and application

Abstract

The invention discloses a method for recovering tungsten from waste SCR catalyst regeneration waste alkali liquor and application. An evaporation concentration crystallization method is adopted to separate a tungsten element and other substances from an alkali solution, and the separation efficiency of the tungsten element and other substances is effectively improved by controlling the concentration of sodium hydroxide in the evaporation concentration process. Then, carbonate ions are removed through acid treatment, and a scheelite concentrate is obtained through the process of adding magnesium sulfate to remove impurities and adding calcium oxide to separate the tungsten element. By adopting a manner of firstly adding acid to remove the carbonate ions, the carbonate ions can be prevented from entering the next working procedure to consume magnesium sulfate; and after the contents of an arsenic element, a silicon element and a phosphorus element are counted, a sufficient amount of magnesium sulfate is added into secondary treatment liquid, so that the situation that the arsenic element is not sufficiently precipitated due to the existence of the silicon element and the phosphorus element is avoided. According to the method for recovering the tungsten, the aims that the precipitation rate of the tungsten element in the waste alkali liquor can be larger than 91%, no arsenic element is detected in the recycled product scheelite concentrate, and the content of tungsten trioxide is larger than 65% are achieved.

Description

technical field [0001] This application relates to the technical field of secondary resource utilization, in particular to a method and application for recovering tungsten from spent SCR catalyst regenerated waste lye. Background technique [0002] In coal-fired power plants, the denitrification activity of SCR catalysts for denitrification gradually decreases due to the poisoning of active components, aging and other reasons with the increase of operating time. When the activity is lower than the design deactivation threshold, it must be replaced layer by layer. At present, commercial SCR denitration catalysts are vanadium-titanium catalysts, and their main components include 80~85wt% TiO 2 , 0.5%~1wt%V 2 o 5 , 4~10wt%WO 3 , and SiO 2 、Al 2 o 3 and other structural auxiliary components. The V, W contained in the waste SCR denitration catalyst and the heavy metals such as Fe, As, Pb adsorbed during use will cause serious harm to the environment. At the same time, val...

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Problems solved by technology

During the leaching process, some valuable metals in the spent SCR denitrification catalyst will be dissolved in the leach solution, and if this part of the leach solution is directly discharged, it will cause a waste of resources

At the same time, some impurities will also be mixed into the leach solution, which will affect the recovery of valuable metals in the leach solution. For example, when recovering tungsten, the arsenic element mixed into the leach solution will increase the recovery of tungsten. Difficulty of element process and influence on recovery efficiency of tungsten element

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