Vanadium and tungsten separating and purifying method for spent vanadium and tungsten SCR (selective catalytic reduction) catalysts

Abstract

The invention discloses a vanadium and tungsten separating and purifying method for spent vanadium and tungsten SCR (selective catalytic reduction) catalysts. The method comprises the following steps: a spent catalyst is pretreated to obtain titanium slag and a vanadium and tungsten solution; the vanadium and tungsten solution is extracted for separation, and an obtained vanadium-rich raffinate is treated again to obtain vanadium pentoxide; a tungsten-rich organic phase obtained through separation is subjected to two-stage extraction for tungsten extraction after back extraction, a product is subjected to back extraction again to obtain an ammonium tungstate solution, and the ammonium tungstate solution is treated to prepare ammonium paratungstate. The blank of lack of a vanadium and tungsten separating, purifying and recovering technology for the spent vanadium and tungsten SCR catalysts in the denitration industry is filled up completely, the recovery rates of vanadium and tungsten both exceed 95%, the obtained vanadium pentoxide and ammonium paratungstate products all meet the high-purity standard, and the purity is higher than 99%.

Description

technical field

[0001] The invention belongs to the field of solid waste treatment, in particular to a method for separating and purifying vanadium and tungsten of spent vanadium and tungsten-based SCR catalysts. Background technique

[0002] my country is a big country in energy production and consumption. The energy supply is dominated by coal, and oil and natural gas resources are in short supply. Coal-fired power generation is mainly through direct combustion. Coal combustion produces a large amount of soot, nitrogen oxides (NOx), sulfur oxides (SOx), mercury and other heavy metal oxides and a large amount of carbon dioxide gas.

[0003] Nitrogen oxides (NOx) are one of the main air pollutants, which can cause acid rain, photochemical smog, reduction of stratospheric ozone and increase of near-surface ozone concentration. How to effectively control NOx emissions has become an important topic of concern in current environmental protection. Among many denitrification tec...

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