Abstract: The invention relates to a freely flowable, soil conditioner consisting of a granular perlite with a coating on the externally accessible surface of the perlite grains of unfired clay. The invention also relates to a process for the preparation of the soil conditioner in which a clay slurry is sprayed onto the perlite grains.

Abstract: The invention relates to a freely flowable, soil conditioner consisting of a granular perlite with a coating on the externally accessible surface of the perlite grains of unfired clay. The invention also relates to a process for the preparation of the soil conditioner in which a clay slurry is sprayed onto the perlite grains.

Abstract: A lightweight building material comprises expanded perlite as an additive and a bonding agent structure consisting of an alkalisilicate and containing pores formed by foaming and/or expansion. The pore content which results from the pore structure of the bonding agent amounts to 85 to 99% by volume, with bulk densities of 40 to 200 kg/m.sup.3, and strengths of 0.01 to 0.5 N/mm.sup.2. In a method for producing a lightweight building material mortar mixes of the following composition are used:70 to 85% by volume of perlite (bulk density from 20 to 150 g/l. grain-size from 0 to 6 mm)23.0 to 2.5% by volume of water-glass (38 degrees Be)25.0 to 5.0% by volume of water1.0 to 0.10% by volume of hardener2.0 to 0.05% by volume of air-entrainer.