Abrasive water-jet technology waste and its processing possibilities

Abstract

The paper is dealing with the environmental research of waste material rising from abrasive water-jet cutting. On the occasion of disposal of the slurry from the overfull collector tank in the Laboratory of the Liquid jet of the Department of Physics at the Technical University of Ostrava the waste material was studied. Samples from different points of the catcher were collected into the beaks, dried up and consequently their elemental and structural composition has been analyzed. The results were primarily evaluated from the viewpoint of effectiveness of further abrasive recycling and usage (either as an abrasive - for this reason the residual cutting ability of the grains was discussed, or as a fine powder material for other applications - the size and shape of the grains was considered). Second viewpoint which was discussed was potential environmental hazard arising from the normal disposal of the waste material. The analysis of dried slurry samples was carried on by electron microprobe. Twenty one samples of waste mixture from various parts and depths of the tank were analyzed and compared with samples of non-used abrasive material. It was proved that abrasive material which had undergone the process of cutting was significantly impaired. It should be recycled in some cases but careful economic calculation taking into account all additional costs connected with separation of suitable abrasive fraction and its drying should be necessary.

X-rays analysis provided information about chemical composition of the waste material. Most of the sludge was from abrasives, namely almandine. Higher contents of magnesium oxide, lower contents of aluminum oxide and higher contents of iron oxide, however, was probably caused by presence of other abrasive materials, such as olivine or zirconium which had been also used for cutting during the working period of the system. No potentially harmful material was detected by the X-ray analysis. It can be therefore stated that waste material from the water-jet cutting can be disposed on a common landfill without any restrictions.