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Method for recycling metal palladium from waste palladium-aluminum oxide catalysts

A catalyst and alumina technology, applied in the field of recovering precious metals, can solve the problems of long static roasting time, low palladium recovery rate and high processing cost, and achieve the effects of reasonable reagent matching, high recovery rate and stable process

Active Publication Date: 2016-01-20
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The purpose of the invention is to overcome the problems of low palladium recovery rate, high processing cost and complicated process in the prior art, and provide a method for recovering metal palladium in a waste palladium-alumina catalyst
[0013] 1) The present invention adopts a fluidized draft roasting process to quickly and efficiently decarbonize to solve the problems of long static roasting time and high energy consumption

Method used

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  • Method for recycling metal palladium from waste palladium-aluminum oxide catalysts

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Experimental program
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Effect test

Embodiment 1

[0027] Use belt machine, grate machine or tunnel kiln for roasting, the material layer height is 120mm, the roasting temperature is 560°C, the exhaust air speed is 1.9m / min, the exhaust negative pressure is 2200Pa, the roasting time is 10-12min, the decarbonization The removal rate reaches 100%.

[0028] Pour calcined sand into a ball mill, the ball mill is an anti-corrosion ball mill, the mass ratio of grinding liquid to solid is 3:1, and the time is 20 minutes; the temperature of hot water is 80°C; the reducing agent is a mixture of formic acid and sodium formate, and the mass ratio of the two is 2: 1. The dosage is 1.5 times the molar ratio of the palladium content. After grinding-reduction, the particle size of the reduced slag is finely ground and the specific surface area is greater than 2500cm 2 g -1 , the reduced palladium content in the slag reaches over 95%.

[0029] Pour the reduction slag into the stirring extractor, then directly add hydrochloric acid, hydrogen...

Embodiment 2

[0031] Use belt machine, grate machine or tunnel kiln for roasting, the material layer height is 200mm, the roasting temperature is 600°C, the exhaust air speed is 2.2m / min, the exhaust negative pressure is 3500Pa, the roasting time is 10-12min, the decarbonization The removal rate reaches 100%.

[0032] Pour calcined sand into a ball mill, the ball mill is an anti-corrosion ball mill, the mass ratio of grinding liquid to solid is 3:1, and the time is 30 minutes; the temperature of hot water is 90°C; the reducing agent is a mixture of formic acid and sodium formate, and the mass ratio of the two is 1: 1. The dosage is 1.8 times the molar ratio of the palladium content. After grinding-reduction, the particle size of the reduced slag is finely ground and the specific surface area is greater than 2500cm 2 g -1 , the reduced palladium content in the slag reaches over 95%.

[0033] Pour the reducing residue into the stirring leaching device, then directly add hydrochloric acid, ...

Embodiment 3

[0035] Use belt machine, grate machine or tunnel kiln for roasting, the material layer height is 250mm, the roasting temperature is 650°C, the exhaust air speed is 2.5m / min, the exhaust negative pressure is 4500Pa, the roasting time is 10-12min, the decarbonization The removal rate reaches 100%.

[0036] Pour calcined sand into a ball mill, the ball mill is an anti-corrosion ball mill, the mass ratio of grinding liquid to solid is 3:1, and the time is 45 minutes; the temperature of hot water is 95°C; the reducing agent is a mixture of formic acid and sodium formate, and the mass ratio of the two is 1: 2. The dosage is twice the molar ratio of the palladium content. After grinding-reduction, the particle size of the reduced slag is finely ground and the specific surface area is greater than 2500cm 2 g -1 , the reduced palladium content in the slag reaches over 95%.

[0037] Pour the reduction residue into the stirring leaching device, then directly add hydrochloric acid, hyd...

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Abstract

The invention belongs to the technical field of recovery of noble metals from waste catalysts through wet process and particularly relates to a method for recycling metal palladium from waste palladium-aluminum oxide catalysts. The process of the method mainly comprises the following steps: fluidizing, oxidizing and roasting; pre-grinding, reducing and activating; and oxidizing and leaching. The method specifically comprises the following steps: quickly roasting and decarbonizing waste catalysts at 550-650 DEG C in the air atmosphere; cooling the waste catalysts and then finely grinding, reducing and pre-treating the waste catalysts in a reducer-containing hydrothermal solution system; and oxidizing reduction slag in a hydrochloric acid and oxidant system to leach palladium. Through the method for recycling the metal palladium from the waste palladium-aluminum oxide catalysts, the problem of low leaching rate of palladium from palladium-aluminum oxide based catalysts of the petroleum chemical industry in the prior art can be solved. The method is short in process, simple to operate and low in production cost; and the leaching and recycling rate of palladium reaches over 99%.

Description

technical field [0001] The invention relates to a method for recovering precious metals from waste catalysts, especially a method for recovering palladium from waste palladium-alumina catalysts. Background technique [0002] Aluminum catalysts are widely used in the reforming, isomerization, disproportionation, cracking and other processes in the petrochemical industry and fine chemical industry, and have good catalytic properties. During use, the catalytic activity will be lost due to the carbon on the surface, the melting of the carrier, the penetration and encapsulation of precious metal particles, etc., and it needs to be replaced regularly. [0003] At present, there are the following mainstream treatment processes for the treatment of spent catalysts: 1. Reuse through washing, modification, reduction and other means; 2. Use spent catalysts as raw materials to re-produce other valuable products; 3. Comprehensive recovery of spent catalysts for valuable products metal c...

Claims

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Application Information

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IPC IPC(8): C22B7/00C22B11/00
CPCY02P10/20
Inventor 李骞杨永斌郭宇峰胡龙徐斌姜涛饶雪飞邹强范晓慧李光辉陈许玲张元波彭志伟甘敏
Owner CENT SOUTH UNIV
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