A method for completely reclaiming tungsten trioxide in waste scr catalyst

An SCR catalyst, tungsten trioxide technology, applied in the field of flue gas denitrification, can solve the problems of increasing the primary cost and energy consumption of operation, and achieve the effect of reducing energy consumption

Inactive Publication Date: 2015-09-23
沈阳远大固废处理有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Its disadvantage is that the calcination process greatly increases the cost of building a plant and the energy consumption of operation

Method used

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  • A method for completely reclaiming tungsten trioxide in waste scr catalyst
  • A method for completely reclaiming tungsten trioxide in waste scr catalyst
  • A method for completely reclaiming tungsten trioxide in waste scr catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] In the waste SCR catalyst of this embodiment, V 2 o 5 Accounting for 1.34wt%, WO 3 Accounting for 3.02wt%, MoO 3 Accounting for 0.002wt%, TiO 2 85wt%, SiO 2 Accounting for 7.5wt%. The specific steps for completely recovering tungsten trioxide in the spent SCR catalyst are as follows:

[0038] 1) Pulverization: pulverize the waste SCR catalyst to 150 mesh and set aside.

[0039] 2) Soak powder in water to remove impurities: Soak the crushed waste SCR catalyst with 3.5 times the volume of water to remove the adsorbed arsenic, mercury, alkali metal salts and organic substances, and the filtered wastewater is adsorbed by activated carbon to absorb arsenic, mercury and organic substances. Substances can be recycled.

[0040] 3) Leaching: Add 5 times the volume of NaOH aqueous solution with a concentration of 70wt% to the wet powder after removing impurities, heat it to 145°C, soak for 4 hours, most of the vanadium, tungsten, molybdenum and titanium can be leached, so ...

Embodiment 2

[0057] In the waste SCR catalyst of this embodiment, V 2 o 5 Accounting for 1.34wt%, WO 3 Accounting for 3.02wt%, MoO 3 Accounting for 0.002wt%, TiO 2 85wt%, SiO 2 Accounting for 7.5wt%. The difference from Example 1 is that the specific steps for fully recovering the tungsten trioxide in the spent SCR catalyst are as follows:

[0058] 1) Pulverization: pulverize the waste SCR catalyst to 200 mesh and set aside;

[0059] 2) Soak powder in water to remove impurities: Soak the crushed waste SCR catalyst with 3 times the volume of water to remove the adsorbed arsenic, mercury, alkali metal salts and organic substances, and the filtered waste water is adsorbed by activated carbon to absorb arsenic, mercury and organic substances. After the substance is recycled;

[0060] 3) Leaching: add 4 times the volume of NaOH aqueous solution with a concentration of 80wt% to the wet powder after impurity removal, heat to 150°C, soak for 5 hours, vanadium, tungsten, molybdenum and titan...

Embodiment 3

[0067] In the waste SCR catalyst of this embodiment, V 2 o 5 Accounting for 1.34wt%, WO 3 Accounting for 3.02wt%, MoO 3 Accounting for 0.002wt%, TiO 2 85wt%, SiO 2 Accounting for 7.5wt%. The difference from Example 1 is that the specific steps for fully recovering the tungsten trioxide in the spent SCR catalyst are as follows:

[0068] 1) Pulverization: pulverize the waste SCR catalyst to 300 mesh and set aside;

[0069] 2) Soak powder in water to remove impurities: Soak the crushed waste SCR catalyst in 4 times the volume of water to remove the adsorbed arsenic, mercury, alkali metal salts and organic substances, and the filtered wastewater is adsorbed by activated carbon to absorb arsenic, mercury and organic substances. After the substance is recycled;

[0070] 3) Leaching: add 6 times the volume of NaOH aqueous solution with a concentration of 60wt% to the wet powder after impurity removal, heat to 140°C, soak for 3 hours, vanadium, tungsten, molybdenum and titanium...

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Abstract

The invention relates to the field of flue gas denitration, and specifically relates to a method capable of completely recycling tungsten trioxide from an SCR catalyst. The method comprises the following steps: soaking grinded waste catalyst in water with a volume three to four times as large as that of the waste catalyst to remove the impurities; adding an excess alkali solution with a concentration of 60 to 80wt% into the purified powder, soaking for 3 to 5 hours at a temperature of 140 to 150 DEG C, filtering, condensing the filtrate to recycle the alkali, adding acid into the condensed liquid from which the alkali has been crystallized to adjust the pH value to a range of 7 to 8, filtering to remove the generated silicic acid so as to remove the silicon element, adjusting the pH value of filtrate to 10 or more, boiling the filtrate to carry out tungstate radicle uniformity, cooling the filtrate temperature to 60 to 80 DEG C, dropwise adding the filtrate into 8-12 mol / L nitric acid with a volume as large as that of the filtrate, cooling, and filtering so as to obtain high purity yellow tungstic acid. The method can carry out complete sodium modification on tungsten trioxide without burning, thus low level of tungsten trioxide can be completely converted into tungstic acid, moreover, and the silicon element is completely removed, so the one-time cost of factory building and operation consumption are both largely reduced.

Description

technical field [0001] The invention relates to the field of flue gas denitrification, in particular to a method for completely recovering tungsten trioxide in waste SCR catalysts. Background technique [0002] Selective Catalytic Reduction (SCR) flue gas denitrification technology has the advantages of high denitrification efficiency, good selectivity, maturity and reliability, etc. It is widely used in thermal power plants and is the mainstream of denitrification of coal-fired units. The main chemical components of catalyst active materials for SCR denitrification There is TiO 2 , V 2 o 5 、WO 3 and MoO 3 , these components account for more than 90% of the catalyst composition. However, on the one hand, metals such as tungsten, vanadium, and titanium are all imported from abroad, and the cost is very expensive. On the other hand, the catalyst is a kind of consumable. After a period of use, it will gradually lose its original function and needs to be activated. At pres...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G41/02
CPCY02P20/584
Inventor 李锋吕腾飞杨俊杰王一罕
Owner 沈阳远大固废处理有限公司
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