Processes of Oxidation in Bentonite Sands

conference paper

English

A new technology of physically and chemically treatment of green sand system, which contain water with radical oxidants is not yet used in Czech foundries. U.S. foundries have already started to exploit Advanced Oxidation technologies with very good results. Therefore the Department of Foundry Engineering of BUT investigated the influence of radical oxidants in green sand systems. The treatment is based on effects of oxidants and external sources of energy reacting with water and components in molding sands. Organic compounds of pyrolytic reaction of seacoal, resin binders, deactivated bentonite and other substances contaminate the molding sands. The oxidants (ozone and hydrogen peroxide) in ultrasonic aditated water, and added to bentonite sand by mulling, will react with and destroy these deposits. This cleaning of the particles will allow for better clay and sand particle interaction and binding with increasing the sand strength. The green compressive strength of production bentonite sand has been improved up to 23 %, the performance in molding system has been better. Introduction of complex oxidants technique into the foundry sands enables the elimination of noxious combustion products and other material originating by contact with cast metal. The AO treatment induced drops of 77 % benzene, 73 % of toluene, 91 % of ethylbenzene, 94 % of m + p-xylene, 95 % of o-xylene, 95 % of naphthalene and other polyaromatic molecules A new process is presumed to be a part of the no-waste technologies acceptable from the point of view of environmentally benign conditions in the foundry workshop (priority in EU).

Advanced oxidation processes, Ozone, Hydrogen peroxide, Sonochemistry

RUSÍN, K., HRAZDIRA, D., CIGANEK, M., BENEŠ, J.

2005

14. 9. 2005

University of Ljubljana

Ljubljana

12

23

12