Building prod. mfr. from clay and cement - by extrusion of clay paste contg. plasticiser added after rest period

摘要

Method of mfr., without firing, of building prods. from clay, as described in the parent patent, in which the clay was mixed with cement and inert materials and the water added to obtain a paste. In this addition the paste is shaped by extrusion, kept in a moist chamber then dried, the paste being allowed to dwell at rest for a period then mixed with a plasticiser. The compsn. comprises 30-50 wt.% clay, 30-60% inert materials and 6-20% cement by wt. Part of the mixing water may be added to form the initial paste, (13-18% by wt. of the starting materials) and the remainder (2-4%) with 0.2-1 wt.% plasticiser. The rest period is pref. 1-4 h. The plasticiser is pref. molasses or polynaphthyl methane sulphonate. The rest period allows prodn. of a fluid paste, the hardening time of which is increased, facilitating extrusion.