Recovery and Refining of Precious Metal Catalysts

Posted by Tylor Keller on April 29th, 2019

A precious metal catalyst refers to a precious metal material that changes the rate of chemical reaction but does not participate in the reaction and almost all precious metals can be used as catalysts. The commonly-used precious metal catalysts are platinum, palladium, rhodium, silver, and rhodium, of which platinum and rhodium are the most widely used. Many reactions can be catalyzed by various heterogeneous or homogeneous precious metal catalysts. Therefore, precious metal catalysts play a important role in many fields. Since precious metal catalysts are a very scarce resource, the recovery and refining of precious metal catalysts is a very important way to reduce costs and save resources.

The catalyst is not permanently used, and when used up, platinum group metals (PGM) such as platinum, palladium, rhodium and ruthenium can be recovered from the catalyst. Equipment used by refineries to treat spent catalysts typically includes rotary and crucible furnaces, kilns, roasters, thermal processors, pulverizers, granulators, screens, blenders, auto samplers, reactors, dissolvers, precipitators, electrolytic cells, and filter presses. Sampling and analysis are two important steps to ensure the recovery of PGM from spent catalyst.

The choice of sampling method is generally critical to the amount of precious metal recovered from the spent catalyst. Precious metal refineries typically use these three sampling methods: dry sampling, melt sampling, and solution sampling. The choice of method depends on the type of material to be processed and the amount of precious metal. Dry sampling is the most complex of the three sampling methods and is suitable for use when the material is not soluble in solution or the material structure is not suitable for melt sampling. Dry sampling is difficult to achieve true uniformity, so refineries using this technology must properly prepare spent catalysts prior to dry sampling for maximum sampling accuracy. Melt sampling and solution sampling involve reducing the spent catalyst and its PGM to a slurry and a liquid solution respectively, so that the precious metal content can be accurately determined.

The precious metal content of the sample needs to be determined after obtaining the sample. The sampled materials need to be measured using specialized instruments for material analysis, including machines capable of performing X-ray fluorescence measurements to identify contaminants still contained in the sample, atomic absorption and inductively coupled plasma emission spectrometers, and tools for performing classic volumetric, gravimetric, and fire assay techniques. The type of material to be determined will determine the analytical method and equipment used in the assay.

When choosing a precious metal refiner, you should understand some of the key steps in the refinery process and how the various equipment is applied. Taking Alfa Chemistry as example, this company has extensive experience in recovery and refining of precious metal catalysts, and committed to providing customers with precious metal waste recycling services in a variety of industries, including recovery and refining of heterogeneous/homogeneous catalysts in petrochemical, fine chemical and pharmaceutical industries, and precious metal alloys in fiberglass and jewellery industries. So far, Alfa Chemistry has overcome a series of technical problems through scientific and technical experiments and obtained new catalysts with high recovery rates. For example, Alfa Chemistry has made breakthroughs in the recovery of rhodium octoate catalyst waste materials to obtain fresh rhodium catalysts.

In addition to precious metal catalysts recovery and refining services, Alfa Chemistry also offers a range of catalysts including organic catalysts, phase transfer catalysts, photocatalysts, metal catalysts and non-metal catalysts to meet the needs of customers in a variety of industries.