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A process for the recovery of adsorbed palladium from spent silica

A technology of palladium salt and silica gel, applied in the field of precious metal recovery, can solve problems such as destroying the carrier structure

Inactive Publication Date: 2007-03-21
COUNCIL OF SCI & IND RES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Methods known in the prior art for recovering metals from supported catalysts also utilize mineral acids, which necessarily destroy the support structure

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] Take 500 g of spent silica in a porcelain dish, where palladium exists as a mixture of palladium phthalocyanine complexes adsorbed on silica gel, and keep it in an air atmosphere in a muffle furnace at 400°C for 3 hours, then cool it to room temperature. Get 1000 milliliters of 2 mol / liter hydrochloric acid aqueous solution in 5 liters of round-bottomed flasks that heating mantle and thermocouple are equipped with, the material in the round-bottomed flasks is heated at constant temperature. The silicon oxide treated above was added, and all the materials in the round bottom flask were kept at a constant temperature. The above treated silica was added and the whole was refluxed at 90°C for 5 hours. After cooling to room temperature, it was filtered using a Buchner funnel, followed by washing with 0.5 mol / l aqueous hydrochloric acid and drying in an oven at 100°C. The pH of the palladium-containing filtrate is raised to 6 and the resulting sediment is filtered in order ...

Embodiment 2

[0075] Take 500 g of spent silica in a porcelain dish, and keep it in an air atmosphere in a muffle furnace at 700°C for 3 hours, and then cool it down to room temperature. Get 1000 milliliters of 2 mol / liter hydrochloric acid aqueous solution in 5 liters of round-bottomed flasks that heating mantle and thermocouple are equipped with, the material in the round-bottomed flasks is heated at constant temperature. The above treated silica was added and the whole was refluxed at 90°C for 5 hours. After cooling to room temperature, it was filtered with a Buchner funnel and washed with 0.5 mol / L hydrochloric acid. The silicon oxide was then dried in an oven at 100°C. The pH of the palladium-containing filtrate is raised to 6 and the resulting sediment is filtered in order to remove impurities, especially silicon oxides, iron and other metals. The sediment was collected and dried. The pH of the filtrate obtained at pH 6 was raised to 9.3, and the sediment was collected and dried. ...

Embodiment 3

[0078] The above experiment was repeated except that the silicon oxide was fired at 300°C. Palladium could not be recovered from the sediment obtained after adjusting the pH of the filtrate obtained after acid digestion to different values ​​of 6, 9 and 11.

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PUM

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Abstract

The present invention relates to a process for the recovery of precious metals from spent catalysts or adsorbent or inorganic waste. More specifically a process is provided for the recovery of palladium from silica, which is used as an absorbent in column chromatography or as a catalyst support in many catalysts. The process includes burning the spent silica to oxidize the organic component of the adsorbed Pd-complex, digesting the cooled residue with a mineral acid, filtering the obtained solution to separate out silica residue, adjusting the pH of the filtrate to remove precipitate impurities and raising the pH of the purified filtrate to recover a palladium salt.

Description

technical field [0001] The present invention relates to the recovery of precious metals from spent catalysts or adsorbents or inorganic waste, more particularly the process described relates to the recovery of palladium from silica which is used as an adsorbent in column chromatography or as a catalyst support in many catalysts . Background technique [0002] Noble metal ions and their complexes have many industrial applications such as supported catalysts and performance chemicals in the fine chemicals industry. For example, the metals Ag, Au, Pd, Pt, and Rh are used as catalysts for oxidation, hydrogenation, and dehydrogenation reactions in various industrial applications. Various polymer-modified silicas, zeolites and / or various clay materials are used as supports for these metals. Likewise, coordinated metal complexes of Pd, Pt, and Rh are used as commercial catalysts for hydroformylation and hydrogenation reactions under homogeneous conditions. However, because metal...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B11/00C22B7/00C22B3/06C22B3/26C10B33/14C01B33/10C01B33/14C22B3/44C22B11/02
CPCC22B7/007C22B11/026C22B3/44C22B11/048Y02P10/20
Inventor A·B·博里查H·C·鲍尧伊R·V·贾斯拉P·高希P·K·高希
Owner COUNCIL OF SCI & IND RES