A method and device for recovering metal oxides from waste flue gas denitrification catalyst

Abstract

The invention discloses a method and an apparatus for recycling metal oxide from a waste flue gas denitration catalyst. The method comprises the following steps: S1, the catalyst is crushed and concentrated sulfuric acid is added for acidolysis, after acidolysis, water is added to obtain a titanyl sulfate solution; S2, the titanyl sulfate solution is filtered, filter residues are standby, a filtrate is heated, condensed and hydrolyzed for obtaining a hydrolysate; S3, the hydrolysate is filtered to obtain a filtrate and a metatitanic acid deposition; S4, salt treatment, a drying and a calcination are carried out for the metatitanic acid deposition, and TiO2 is obtained; S5: sedimentation treatment is carried out for the filtrate in the S3, after filtering, a upper level clear liquid is taken, excessive NH4Cl is added into the clear liquid for reaction, after filtering, andammonium metavanadate deposition is obtained; the ammonium metavanadate deposition is calcined, and V2O5 is obtained; S6, excessive ammoniacal liquor is added into the filter residues in the S2 for reaction, and a filtering is carried out; a filtrate is heated to generate a ammonium paratungstate crystal; the ammonium paratungstate crystal is dried and calcined, and WO3 is obtained. According to the method, V, Ti and W three components can be completely separated.

Description

technical field [0001] The invention relates to a method and a device for recovering metal oxides from waste flue gas denitrification catalysts, and belongs to the technical field of waste flue gas denitrification catalyst recovery. Background technique [0002] SCR denitrification technology is a necessary means for power plants to achieve ultra-clean emissions. As the core part of SCR denitrification technology, the catalyst will lose its activity due to wear or blockage during operation. Partially regenerable catalysts can continue to be used after regeneration, while non-regenerable catalysts face the situation of rational utilization and disposal (even if regenerable catalysts are regenerated 2 to 3 times, they cannot be regenerated and need to be rationally utilized and disposed of). At present, landfill is the way to dispose of waste denitration catalysts in foreign countries, but there are many thermal power plants in my country, and the amount of waste denitration c...

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Problems solved by technology

But adopting above-mentioned high-temperature roasting method to reclaim the denitrification catalyst consumes more energy, is not suitable for suitability for industrialized production at all; The method for reclaiming the denitrification catalyst with lye treatment first, then with acid solution treatment, reagent waste is serious on the one hand (such as required lye is excessive , the excess lye is reused to neutralize the acid solution), which is not conducive to the effective utilization of resources. On the other hand, in the recovery process of the catalyst, Na 2 SiO 3 colloid, then when the solid-liquid separation is carried out by filtration, the colloid is easy to stay on the filter paper together with the precipitate, resulting in incomplete separation, which in turn leads to TiO 2 、WO 3 and V 2 o 5 The extraction purity is low, and the extraction efficiency is also low; in addition, in the prior art, the extraction method of titanium dioxide is mostly sodiumization first, and then adding sulfuric acid to gradually separate, which is complicated to operate and consumes more raw materials; it is directly recovered by acid solution treated denitrification catalysts, although their production of TiO 2 It can be connected with the production process of titanium dioxide, and the industrialization benefit is also obvious, but according to the record of CN 103130265 A, it can only convert TiO 2 with WO 3 , V 2 o 5 separated, while V 2 o 5 and WO 3 All belong to metal oxides with similar properties, and the waste flue gas denitrification catalyst contains TiO 2 and glass fiber mixture, so the V 2 o 5 and WO 3 It's not easy to separate

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