Influence of the charge properties on the milling tools wear during intensive milling in liquid environment

Abstract

Grinding belongs to the basic technological operations in the treatment and processing of minerals. The method of the intensive grinding in a liquid environment has become attractive for the preparation of technologically advanced materials of the high fineness. Its choice was motivated by the intensification of dispersion and by the protection of ground powder against oxidation. The result of energy and material interactions among the grinding media and grinding environment is the wear of the grinding media and contamination of the ground material. The hardness of the particles has an important influence on the rate of wear. Particles with hardness lower than that of the surface of milling tools cause much less wear than harder particles. The wear rate becomes much more sensitive to the ratio of the abrasive hardness Ha to the surface hardness Hs when Ha/Hs <¡­1.The paper deals with the influence of four minerals with various microhardness (corundum, quartz, silicon and magnesite) on the steel milling tools wear during intensive milling.. Experiments were performed in a vibration mill in methanol under same conditions. The grinding time was changed in a geometric sequence from 0,125 to 4 hours. The newly created surface area providesa basic information on grinding. The specific surface area was determined by the standard Brunauer-Emmett-Teller (BET) method using the appratus Gemini 2360 (Sylab, Austria). The concentration of iron was determined by AAS (SpectrAA-30, Varian, Australia). It was confirmed that the rate of ball wear depends on the hardness of feed materials. It was found that the relation between the contamination of the ground powders by wear and the specific surface area increment is linear and the slope depends on the microhardness of the ground material.

Keywords

• hardness
• milling
• vibration mill
• wear