First of all, before moving towards the main point, you should know the basics of it. A catalytic converter is a gaseous emission control device used to reduce the pollutants and toxic gases in the vehicle gas from the internal combustion (burning) engine to pollutants by oxidation. These converters are used in vehicles with an internal combustion engine. The burning of fuel and other combustion processes occurs in the internal combustion engine. The internal combustion engine includes kerosene heaters, stoves, and lean-burn engines. It is fueled with diesel or gasoline, mostly known as petrol, to combust. An autocatalytic converter is the automotive catalytic converter that is a part of the vehicle exhaust system. It is designed to decrease the gas releasing into the atmosphere. It plays an efficient role in the automotive catalytic converter.
Structure of autocatalytic converters
The structure of the autocatalytic converter is similar to any other primary catalytic converter. The autocatalytic converter is made of steel, or sometimes ceramic shell with a structure like a honeycomb covered shielded with the catalytic substances from precious group metals that are mostly platinum (Pt), rhodium (Rh), and palladium (Pd). Substances that are stable with the environment are acquired through the outlet of the autocatalytic converter. This kind of structure makes the active surface large and the surface of contact of catalytic substances with the exhaust gases.
Techniques for Automotive catalytic recovery
There are some hydrometallurgical and pyrometallurgical processes used for the recovery of catalysts of PGM. As stated earlier, PGM is platinum group metals consists of six elements from which platinum, palladium, and rhodium are mostly used. Three different techniques can obtain the recovery of catalyst substances from the spent exhaust system. Those three methods are gas-phase transporting, support dissolving, and extraction of solution. The gas-phase transport method includes the volatilization of substances of PGM from catalyst support, whereas the support dissolving technique includes dissolving the catalyst support into the base solutions or non-oxidizing chemicals to inert the PGM substances. The third technique, solution extraction, consists of dissolving the PGM substances with oxidizing acids, which results in the dissolution of catalysts support. Many PGM producers and researchers are finding alternative methods for an efficient automotive catalytic converter instead of these techniques.
The need for automotive catalytic recovery
Automotive catalytic converters have been used widely to limit the exhaust emission. The catalysts used in the process are mostly combinations of platinum, palladium, and rhodium. But since platinum is used in very little quantity in the process, it is more efficient to recover it from the spent gaseous (exhaust) systems. You can also recover 90% of the precious group metals. Without the recovery process, you may invest a high cost for the autocatalytic converter process as they are increasingly demanded. That’s why it is needed to recover the catalysts from the spent catalytic converters to make your process cost-efficient.