Method for preparing vanadium pentoxide by treating vanadium-containing waste sulfuric acid catalyst through two-step method

Abstract

The invention discloses a method for preparing vanadium pentoxide by treating a vanadium-containing waste sulfuric acid catalyst through a two-step method. The pH value is controlled to be 5-6 throughoxalic acid leaching in a first step, namely the leaching rate of vanadium is controlled to be between 65% and 75%, and simultaneously a large amount of impurities (Al, Ni, Cu and the like) are inhibited from being separated out; the PH is controlled to be 1.5-2.0 through sulfuric acid leaching in a second step, the leaching accumulation of vanadium is controlled to be larger than or equal to 90%, meanwhile, a small amount of impurities such as Al are leached, leaching liquid returns to the first step of oxalic acid leaching (when the small amount of impurities leached in the second step return to the first step of leaching, precipitates are generated again and enter slag), and meanwhile, the first-step leaching is completed by utilizing the temperature of the leaching liquid, so that thecost is reduced; leaching residues are washed in the second step, the leaching residues are centrally collected, lime is added to be mixed, and the mixture is sold to a cement plant to serve as clinker of the cement plant; the leaching liquid is prepared after the first step of oxalic acid leaching, vanadium precipitation of ammonium sulfate is directly adopted to prepare an ammonium polyvanadateintermediate product, concentrated sulfuric acid needs to be added in the production process, residual oxalic acid in the leaching liquid completely reacts with the concentrated sulfuric acid to eliminate obstacles for subsequent water treatment, and solid ammonium sulfate prepared after water treatment returns to a production system, and potassium sulfate is purified and sold to potash fertilizer production enterprises to be used as a raw material.

Description

technical field [0001] The invention relates to the technical field of vanadium pentoxide preparation, in particular to a two-step process for preparing vanadium pentoxide by treating waste sulfuric acid catalyst containing vanadium. Background technique [0002] The existing methods for producing vanadium pentoxide are as follows [0003] 1. Sulfuric acid leaching method: high-concentration sulfuric acid leaching of spent catalyst powder, leachate ion exchange to recover vanadium, liquid caustic analysis, ammonium salt precipitation of vanadium, calcination to produce vanadium pentoxide, such as figure 1 shown. [0004] 2. A recycling and processing method and process of a spent vanadium catalyst: step A: washing the spent vanadium catalyst with a solution containing a diester inhibitor and oxalic acid; step B: drying the spent vanadium catalyst to obtain a dry Spent vanadium catalyst; step C: soak the dried spent vanadium catalyst in an oxalic acid solution containing 30...

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Problems solved by technology

[0009] 3. Vanadium extraction by sodium roasting: Because the waste sulfuric acid catalyst contains a large amount of sulfur, it enters the flue gas system during roasting. Environmental protection treatment is difficult and almost impossible. The main defect lies in the flue gas treatment process. The product requires an impurity removal process in the middle, which increases the generation of hazardous waste

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