Method for recycling spent vanadium catalyst through phosphoric acid solution

Abstract

The invention discloses a method for recycling a spent vanadium catalyst through a phosphoric acid solution. The method comprises the steps: after the spent vanadium catalyst reacts with the phosphoric acid solution, filtering and separation are conducted to obtain filtrate I and filter residue I; the filtrate I is subjected to still standing and filtered to obtain filtrate III and primary precipitate I, and the filtrate III is subjected to still standing, filtered and separated to obtain secondary precipitate II and filtrate IV; a potassium oxalate solution is added into the filter residue Ifor sufficient reacting, still standing and filtering are conducted, a solid is washed with water for 2-3 times, and filtrate II and filter residue II are obtained; the filtrate II is returned to replace the potassium oxalate solution, and when the content of vanadium in a solution exceeds 40 g / L, leaching is stopped to obtain a mixed solution; after the mixed solution is treated, potassium sulfate and filtrate V are obtained; after the filtrate V is treated, vanadium pentoxide is obtained; after the primary precipitate I is treated, potassium vanadium phosphate is obtained; and the filter residue II is treated to obtain potassium silicate. According to the method, at the normal temperature, the recovery rate is high, the process is simple, and energy consumption is low.

Description

technical field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for recycling spent vanadium catalysts with phosphoric acid solution. Background technique

[0002] With the rapid development of the sulfuric acid industry, the production capacity of sulfuric acid in my country is about 100 million tons. Catalysts are used in the production of sulfuric acid. This catalyst is a vanadium catalytic system composed of diatomaceous earth as the carrier, vanadium pentoxide as the active component, and alkali metal (Na, K, Cs) sulfate as the co-catalyst. The composition is as follows: the diatomite content is 50-70%, the alkali metal sulfate content is 15-28%, and the active component vanadium pentoxide content is 5-10%. The vanadium catalyst promotes the conversion of sulfur dioxide to sulfur trioxide, which provides a strong guarantee for the mass production of sulfuric acid. However, the active component (pentaval...