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A method for comprehensive recycling of waste PD/Al2O3 catalyst

A waste catalyst and catalyst technology, applied in the direction of improving process efficiency, etc., can solve the problems of platinum group metal dissolution loss, easy agglomeration of products, and difficulty in discharging materials, so as to avoid dissolution loss, alleviate serious agglomeration of calcined sand, and improve The effect of leaching rate

Active Publication Date: 2018-03-20
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the raw materials are not finely ground, the time required for roasting is longer (1-6 hours), the temperature is higher (600°C-850°C), and the leaching rate of aluminum after two stages of digestion-water immersion is only 98.50%.
In order to make sodium hydroxide fully contact with the material and improve its reactivity with alumina, the raw material needs to be moistened with water after being mixed with sodium hydroxide, and the wetted material will undergo sintering reaction under high-temperature roasting conditions, and the product is easy to agglomerate , bonded to the furnace wall, resulting in particularly difficult discharge, in addition, the strong base molten at high temperature will react with platinum group metals, resulting in the dissolution loss of platinum group metals

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Embodiment 1: waste Pd / Al 2 o 3 The catalyst is added with sodium hydroxide containing 1.5 times the aluminum content, placed in a planetary ball mill for mixing and grinding until the grinding fineness is -200 mesh, accounting for 70% to 80%, the mixture after mechanical activation and mixing is taken, and placed in the Calcined in a muffle furnace at 400°C for 100 min, the obtained calcined sand was loose without agglomeration; the calcined sand was leached with 0.01mol / L hydrazine hydrate solution. The leaching rate of aluminum is 99.00%, palladium is all enriched in the slag.

Embodiment 2

[0019] Embodiment 2: waste Pd / Al 2 o 3 The catalyst is added with sodium hydroxide containing 2.0 times the aluminum content, and placed in a planetary ball mill for mixed grinding until the grinding fineness is -200 mesh, accounting for 70% to 80%. The mixture after mechanical activation and mixed grinding is taken, and placed in Calcined at 500°C for 90 minutes in a muffle furnace, the obtained calcined sand is loose without agglomeration; the calcined sand is leached with 0.01mol / L hydrazine hydrate solution. The leaching rate of aluminum is 99.23%, palladium is all enriched in the slag.

Embodiment 3

[0020] Embodiment 3: waste Pd / Al 2 o 3 The catalyst is added with sodium hydroxide containing 2.0 times the aluminum content, and placed in a planetary ball mill for mixing and grinding until the grinding fineness is -200 mesh, accounting for 70% to 80%. The mixture after mechanical activation and mixing is taken, and placed in Calcined in a muffle furnace at 600°C for 40 minutes, the obtained calcined sand is loose without agglomeration; the calcined sand is leached with 0.02mol / L hydrazine hydrate solution. The leaching rate of aluminum is 99.81%, and all palladium is enriched in the slag.

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Abstract

The invention provides a method for comprehensively recycling a waste Pd / Al2O3 catalyst. The method mainly comprises the steps of mixed fine grinding of waste catalyst raw materials and sodium hydroxide, roasting, reduction leaching and the like. The waste catalyst raw materials and the sodium hydroxide are added into a grinding machine at the same time to be finely ground, the effects of finely grinding the materials and uniformly mixing the materials and the sodium hydroxide are achieved, and meanwhile the chemical activity of the materials is enhanced. The mixed materials enable Al2O3 in the raw materials and the sodium hydroxide to react and be converted into Na2O.Al2O3 easily dissolved in water through roasting, and water is added for leaching to dissolve the Na2O.Al2O3 to effectively separate Pd and the Al2O3. To avoid the situation that the Pd is corroded by the sodium hydroxide, and consequently Pd dissolution losses are caused, reduction leaching is adopted in the leaching process, the final aluminum dissolution rate reaches up to 99% or above, the Pd concentration ratio exceeds 49 times, and the recycling rate is larger than 99.99%. The method has the beneficial effects of being short in procedure, easy and convenient to operate, short in leaching time and the like, and is suitable for large-scale application.

Description

technical field [0001] The invention belongs to the field of recovery and utilization of secondary resources, and relates to the comprehensive recovery of waste platinum group metal aluminum-based catalysts, in particular to the recovery of waste Pd / Al 2 o 3 Catalyst recovery method for palladium and aluminum. Background technique [0002] Catalysts containing platinum group metals are widely used in petrochemical industry and automobile industry. At present, the platinum-group metal-containing catalysts commonly used in industry are mainly supported by alumina. During use, the catalyst will gradually lose its activity due to carbon deposition, poisoning and other reasons, which will eventually lead to the failure of the catalyst and become a spent catalyst. Platinum group metals are widely used, but their resources are scarce and their reserves are low. Due to the high content of precious metals in spent catalysts, which is much higher than that of platinum group metal ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B11/00C22B21/00C22B1/02
CPCC22B1/02C22B7/008C22B11/048C22B21/003Y02P10/20
Inventor 李骞杨永斌徐斌饶雪飞姜涛郭宇峰董海刚李光辉范晓慧陈许玲张元波彭志伟甘敏杨凌志胡龙邹强张雁李鸿炜
Owner CENT SOUTH UNIV