Patent GB-529930-A (GB)
Title: Improvements in or relating to siliceous bodies
IPC: C04B33/13
Filed: 1939-06-12
Abstract: 529,930. Glass manufacture ; artificial stone ; catalysts. GARBISCH, N. S. June 12, 1939, No. 17155. Convention date, Aug. 11, 1938. [Class 56] [Also in Groups III and V] A method of using the waste sand that results from the grinding of plate glass consists in heating the material to such a temperature that it is bonded by the pulverised glass which is present. Preferably the material is pressed, while hot and plastic, to form plates, rings bricks, pipes, or bodies of any desired shape. The bodies may be somewhat porous and may be used fcr heat and sound insulation, as packing for absorbers or distilling apparatus, and as scouring bricks or abrasives. The porous structure may be impregnated with catalytic substance, such as vanadium oxide and the like, and used as catalysts in such chemical reactions as the oxidation of naphthalene to form phthalic anhydride, or the oxidation of sulphur dioxide to form sulphuric acid anhydride. The material may be treated first with sulphuric acid, or by magnetic separation, to remove the iron that is present, and additional quantities of ground glass or of blast furnace slag may be added. The material may then be mixed, if required, with an organic binder such as tar or asphalt, or an inorganic binder such as sodium silicate or lime or both together. The mixture is then deposited in moulds of heat-resisting material, such as chrome steel or a ceramic material, and fired. The mould may be coated with silica, gypsum, magnesia, or other material to prevent adhesion. The moulds 13, Fig. 1, may be placed in a shell 11 which is heated internally by gas or electric heaters 14. The shell is reciprocated vertically, during the heating, by an electrically-operated vibrator 12 to settle the material in the moulds. In another construction, the material, after a preliminary heating to the sintering temperature is pressed between rollers to form it into a strip. The material is supplied to a hopper 25, Fig. 2, whence it is discharged by way of a vibrated trough 26, into a rotary kiln 30. Powdered coal may be mixed with the material, before introduction into the hopper, to assist the heating, and burners 33 may be inserted in the kiln. The sintered material as it leaves the kiln passes between rollers 38, 39 by which it is compressed into a strip A that travels through a leer 44. The material may also be fed into moulds which travel through a furnace. On emerging from the furnace, the moulds pass to an hydraulic press by which the plastic is compacted.. In another construction, the material is heated while in a mould, or is placed in heated moulds, and when sufficiently heated is pressed by an hydraulic press. In the apparatus )shown in Fig. 8, the moulds 116 are carried by a rotating table 113 from a receiving station, where they are charged with the sintered material from a rotary kiln 119, through a tunnel kiln (not shown) to an hydraulic press 139. The pressure for shaping the material may be sustained for a larger or shorter time or may be applied as a series of hammer-like impacts. The material may be coloured by the addition of usual colouring oxides, and the finished articles may be coated with glaze by dipping in slips and refiring. A suitable glaze is composed of 32 parts by weight of silica, 6 parts of saltpetre, 7.5 parts of soda ash, 9.5 parts of borax, 39.5 parts of red lead, and 5.5 parts of colouring oxide such as Fe 2 O 3 . The finished bodies also may be coated or impregnated with such materials as linseed oil, shellac, &c. They may be impregnated, also, with chemical substances, such as soluble compounds of metals, and then treated with precipitating agents to fill the pores of the material.