PURPOSE: To perform the title treatment at low cost in less working steps by adding a small amount of a surface treating agent to an inorganic powder and heating the mixture at a specified temperature with agitation using an agitated heat-exchanger drier.
CONSTITUTION: In treating the surface of an inorganic powder (e.g. alumina, silica or calcium carbonate powder) by adding 1-5wt.% surface treating agent (e.g. paraffin or sodium stearate) thereto, the inorganic powder and the surface treating agent are heated at 60-90°C with agitation using an agitated heat- exchanger drier. By this technique, surface treatment of an inorganic powder can be performed at low cost in less working steps. It can be utilized for all kinds of inorganic powders both in the dry and wet systems, can realize uniform surface treatment, and gives a surface treated inorganic powder having very excellent characteristics.
SASAKI HIROSHI