88510 ⎘
Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups - and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups - specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials; Treatment; Heat treatment; Expanding clay, perlite, vermiculite or like granular materials in rotary kilns