Prescious metals in a catalyst
In the modern cars there are a lot of interesting things. It turns out that there are even noble metals in it and the car owner himself can make good money with its help.
Not everyone knows that the so-called exhaust system catalyst or rather, an exhaust gas catalyst contains precious metals of the platinum group. First of all, it is actually platinum, as well as noble metals palladium and rhodium.
A porous ceramic or metal filling is hidden in catalyst housing, where another noble metal is sprayed.
Therefore, after the automotive catalyst fails and this usually happens after 150-200 thousand kilometers, you can take it to special processing companies, which are able to extract precious metal for recycling.
The main nuance of this procedure is that platinum metals are in a form of a very thin layer sprayed onto porous ceramic cells. In fact, the device is conceived as such, so that the contact surface of exhaust gases with metal catalyst is as wide as possible. Therefore, collecting sprayed platinum from 20 thousand square meters of the inner surface of the honeycomb is not so simple. To do this, it is necessary to “rinse” catalyst ceramics with acids, heat, galvanize, crush... But this, in fact, is a problem not of a motorist, but of other people.
How to determine the profit which a catalyst can bring to a driver owing to this? To determine the number of platinoids, an RF spectrometer is used, it is also an X-ray fluorescence analyzer. But first of all, you need to see the catalyst case, pull out the ceramic filler and grind it. Then, correlating the data of spectrometer and mass of ground filling, the receiver determines the price.
The average price of a catalyst that has worked out is from 20 to 150 USD, and you can get them just passing an unnecessary catalyst at the pick-up point. It is interesting that evaluators take into account the current quotations on world exchanges when evaluating. And this figure relative to platinum can experience significant fluctuations, for example: depending on the situation, one ounce in different periods can cost several hundred dollars and one and a half thousand dollars.
The content of precious metals in a catalyst is determined using a spectrometer. Incidentally, it is able to distinguish platinum substitute.
To understand: the content of pure platinum or other platinoids is tenths and hundredths of a percent of the total mass of catalyst filling.
Taking into account how much a new catalyst costs, which will have to be bought to replace a failed one, handing over the old for recycling will be the most rational step. And even if you don’t want to buy a new catalyst and intend to replace it with a substitute, you should still think about recycling. The price is worth the time spent on the delivery of precious recycled materials.
The platinum content in Japanese and Chinese cars is 15% less than in Europe, in catalysts of Russian cars 40% less than rhodium in Europe. In American catalysts, precious metals are half as much as in European ones.
To solve the problems of processing catalysts, hydrometallurgical and pyrometallurgical methods are used. The source for processing contains a large amount of ceramic carrier and an insignificant concentration of precious metals. When processing waste electronics, the source is scrap parts that contain, as a rule, plastic particles in their composition.
The task of recycling automotive parts waste is to obtain semi-finished products suitable for recycling. The hydrometallurgical method for extraction of precious metals for catalysts consists of the following main steps:
Primary leaching of waste with mixtures of acids, the composition of which depends on qualitative and quantitative content of precious metals in source, at temperatures above 100 ° C;
Repeated washing of an acid-insoluble carrier with water;
Drying semi-finished product at 200 ° C and calcining at temperatures of the order of 600 ° C.
When using the pyrometallurgical method for catalysts, waste processing occurs in the following several stages:
Crushing and sorting its particles by size.
Preparation of the initial charge.
Melting of crushed product at a temperature of 3000 ° C in a plasma-arc furnace with the formation of melts of precious metals, ceramics, and metal carriers.
Periodic discharge of slag melts, stratified due to the difference in densities of metals and ceramics: the ceramic melt remains at a top, precious metal melt in collector (copper, iron) is drained from the furnace.
Granulation of a liquid melt.
The heal granulation product, enriched with precious metals by 3-15%, is a suitable raw material for refining plants, which further produce precious metals with the highest degree of purity.
Sale of used catalysts
Old catalysts can be sold to a number of companies associated with refineries with contracts for the recycling of their enriched raw materials. The scope of activity of such companies includes the purchase of spent catalysts from private and legal entities.
Before concluding a contract of sale, the company analyzes the catalyst which valuable element it contains, and in what quantity.
Based on the analysis, the transaction value is determined. On average, for foreign cars prices are per 1 kg of catalyst vary from 50 to 150 USD, depending on the car brand.
Catalysts from Hummer, Land Rover, Infiniti, Jeep GrandCherokee, Lexus, Mercedes-Benz reach the highest costs.