A method for desiliconization and arsenic removal of spent SCR catalyst

An SCR catalyst and arsenic removal technology, applied in chemical instruments and methods, physical/chemical process catalysts, separation methods, etc., can solve the problems of low removal rate, no mention of silicon treatment, low arsenic removal rate, etc. The effect of low leaching rate, raw material and operating cost, and low raw material cost

Active Publication Date: 2021-03-09
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0004] CN 104261415A discloses a method for completely recovering the silicon dioxide in the waste SCR catalyst. The waste SCR catalyst after pulverization is soaked in water to remove impurities, then leached with a concentrated alkali solution and then filtered, and sodium metavanadate is filtered out, and the filtrate is added Sulfuric acid adjusts the pH to filter out the hydroxides of iron and aluminum, then adjusts the pH to obtain silicic acid, and then refines it to obtain silicon dioxide. However, in this method, arsenic, mercury, etc. are only removed by soaking and removing impurities, and the removal rate of gods is low. , even if there is lye leaching, it mainly dissolves titanium, vanadium, tungsten and other oxides, and does not involve further treatment of arsenic, and the concentration of lye used is extremely high, requiring a large amount of acid to neutralize
CN 106396029A discloses a method for removing arsenic from an SCR catalyst. The SCR catalyst is washed with lye and filtered to obtain an arsenic-containing solution, and then the arsenic is removed through oxidation and electrochemical deposition. However, only lye is used to remove arsenic in this method , the removal rate of arsenic is low, and the treatment of silicon is not mentioned

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  • A method for desiliconization and arsenic removal of spent SCR catalyst

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Embodiment 1

[0051] This embodiment provides a method for removing arsenic and desiliconization from a spent SCR catalyst. The content of arsenic in the spent SCR catalyst is 2.2wt%, and the content of silicon dioxide is 4.23wt%. The process flow chart of the method is as follows figure 1 shown, including the following steps:

[0052] (1) Add the spent SCR denitrification catalyst broken to 100 meshes into NaOH solution containing hydrogen peroxide for leaching, the concentration of NaOH solution is 20wt%, the concentration of hydrogen peroxide is 3wt%, and the mass ratio of leaching liquid to solid is 2:1. Leach for 4h at a stirring rate of 200r / min, and then filter;

[0053] (2) The solid phase obtained by filtering in step (1) is washed with water and pickled in turn, and the acid used is sulfuric acid, and then dried at 100°C for 12 hours to obtain a recovered component containing titanium and tungsten, which is used for the preparation of SCR catalyst; The liquid phase continues to b...

Embodiment 2

[0056] This embodiment provides a method for removing arsenic and desiliconization from a spent SCR catalyst. The arsenic content in the spent SCR catalyst is 1.63wt%, and the silicon dioxide content is 4.35wt%. The method includes the following steps:

[0057] (1) Add the waste SCR denitrification catalyst broken to 200 meshes into NaOH solution containing sodium persulfate for leaching, the concentration of NaOH solution is 16wt%, the concentration of sodium persulfate is 5wt%, and the mass ratio of leaching liquid to solid is 4:1, Leach at 75°C for 3 hours at a stirring rate of 300r / min, and then filter;

[0058] (2) The solid phase obtained by filtering in step (1) is washed with water and pickled in sequence, and the acid used is hydrochloric acid, and then dried at 80°C for 15 hours to obtain a recovered component containing titanium and tungsten, which is used for the preparation of SCR catalyst; The liquid phase continues to be separated for the recovery of vanadium an...

Embodiment 3

[0061] This embodiment provides a method for removing arsenic and desiliconization from a spent SCR catalyst. The content of arsenic in the spent SCR catalyst is 0.17wt%, and the content of silicon dioxide is 4.5wt%. The method includes the following steps:

[0062] (1) Add the spent SCR denitrification catalyst broken to 300 meshes into the KOH solution containing potassium persulfate for leaching, the concentration of the KOH solution is 10wt%, the concentration of potassium persulfate is 1wt%, and the mass ratio of the leaching liquid to solid is 5:1, Leach at 60°C for 5 hours at a stirring rate of 250r / min, and then filter;

[0063] (2) The solid phase obtained by filtering in step (1) is washed with water and pickled in sequence, and the acid used is nitric acid, and then dried at 120°C for 6 hours to obtain a recovered component containing titanium and tungsten, which is used for the preparation of SCR catalyst; The liquid phase continues to be separated for the recovery...

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Abstract

The invention provides a method for removing arsenic and silicon from a spent SCR catalyst. The method comprises: leaching the spent SCR catalyst in an alkaline solution containing additives, and then separating the solid from the liquid; The recovered components are used in the preparation of SCR catalysts. The present invention can effectively remove the arsenic and silicon in the spent SCR catalyst by adding additives in the lye, the removal rate of arsenic can reach more than 95%, and the removal rate of silicon can reach more than 50%; the leaching method The leaching rate of vanadium and tungsten in the active components of the catalyst is also improved, and the active components and the carrier are separated to a certain extent, which is convenient for recycling respectively; the method has simple operation steps, mild leaching conditions, low raw material and operating costs, and wide application wide.

Description

technical field [0001] The invention belongs to the technical field of solid waste recycling, and relates to a method for desiliconizing and arsenic removal of spent SCR catalysts. Background technique [0002] As a common gaseous pollutant, nitrogen oxides are the main substances that cause pollution problems such as acid rain and photochemical smog. They mainly exist in various industrial smoke and automobile exhaust. At present, Selective Catalytic Reduction (SCR) is the most commonly used denitrification technology, and the SCR catalyst plays the core role; and the dust and other components contained in the flue gas can easily cause catalyst deactivation and become a waste SCR catalyst. Waste SCR catalysts are hazardous wastes because they contain heavy metals such as vanadium and tungsten or harmful elements such as arsenic. However, the catalyst components themselves still have high utilization value and can be recycled. Therefore, it is necessary to remove harmful ele...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/96B01D53/86B01D53/56B01J23/30
CPCB01D53/8628B01D53/96B01J23/30
Inventor 王兴瑞李会泉陈艳王晨晔赵晨
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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