High-Temperature Processing and Recovery of Cu Catalyst Promoter

Abstract

The following article describes the results obtained from the plasma smelting reduction of a particular type of waste -catalyst with a Cu promoter. The catalyst is used for the process of a selective reduction of nitrobenzene (C6H5NO2) to aniline (C6H5NH2). The plasma smelting occurs in a reducing atmosphere. Six samples of the exhausted catalyst with a Cu promoter were used in the smelting process. The chemical composition of the promoter exhibited a presence of a wide range of elements. Fluorspar (fluorite) and calcium oxide (quicklime) were used as the slag-agent for the given testing. Reducing agent was the powdery graphite -waste from the manufacture of the graphite semi-finished product. The results of experiments, carried out at 80 kVA in the plasma reactor, proved that this type of catalyst can be, in fact, disposed of using the plasma technology. Recyclability of the metal contained in this waste is high; Cu ranges around 88%. Moreover, the article describes the chemical analysis of the slag, fly ash and the composition of synthesis gas in all samples of the processed catalyst.Keywords: Waste, Catalyser, Cu promoter, Plasma technology IntroductionIn Slovakia and the Czech Republic, recently more attention is paid to the waste treatment using the thermal plasma. First results of experiments are available describing the outcome of the processes of high temperature waste treatment in the plasma reactor; for example in the area of municipal waste, fly ash from thermal power plants or from hazardous asbestos-based waste [1][2][3][4]. Technologies using the thermal plasma for the refining processes or for the processing and recycling of the scrap metal have been known for several decades, especially in the developed countries of North America, Western Europe and Japan.Presently, the technology of plasma melting and gasification is developed mainly in the area of recycling and disposal of hazardous waste, radioactive materials, nuclear weapons, and also in refining high-purity substances.Temperatures obtained from the low-temperature thermal plasma technology are currently the highest temperatures used in practice [5][6][7]. In such extreme temperature conditions the decomposition of larger molecules of the hazardous organic matter into atoms and radicals occurs. Moreover, if the high temperature melting takes place in reduction conditions and compliance with the prescribed methodology for the processing, the formation of the polycyclic aromatics does not take place.Today, the results from the treatment of various industrial waste by plasma technology are well known [8]. The recovery rate of precious metals of various metallic waste is a focus of many articles and papers [9][10][11][12]. A separate domain of the plasma technology use is its inclusion within the liquidation process of catalysts [13]. In this area, as well, the results are well known as they were obtained under various conditions using the low-temperature thermal plasma [14][15]. A by-product of the waste processing is always synthesis gas and s...

High-temperature processing and recovery of autocatalysts

“…The plasma reactor 15 was used to melt autocatalysts based on cordierite and autocatalysts based on Cr/Ni strips.…”

“…The by-products from processing this waste are always syngas and slag. [12][13][14][15] The exploitation of the energy from syngas is the subject of paper 16 .…”