GB370889A - Process for preparing carbon dioxide and siliceous materials - Google Patents

Abstract

<PICT:0370889/III/1> <PICT:0370889/III/2> Carbon dioxide and metal silicates other than magnesium silicate are prepared by heating a stream of metal carbonate other than magnesium carbonate, silica and water under pressure to a temperature above the boiling-point of water whereby carbon dioxide is formed and separated from the metal silicate. Siliceous material such as diatomaceous earth, quartz, opaline silica may be used, and the carbonates of barium, copper, iron, and zinc are specified as suitable. The speed of the reaction is dependent upon the pressure, which may be from 150 lbs./sq. in. up to 1000 lbs./sq. in. or higher. Thus the siliceous material, metal carbonate, and water are introduced into a grinder 11, Fig. 1, via the hopper 10 and pipe 12, and the ground slurry forced into the heater 15 by a pump 13. Heater 15, Fig. 2, comprises an inner shell 17 jacketed by an outer shell 16. These shells are in communication through a series of pancake pipe coils 24, through which the heating medium passes via inlet 25 and exit 26 into the shell 16. Transverse baffles 21, 22 serve to further subdivide the inner shell 17 into which the slurry enters via pipe 14. Carbon dioxide separating passes via pipe 29, cooler 30, and pipe 31 to containers 33, and the metal silicate and steam passes to the dryer 36 through the exit 18. The metal silicates thus obtained are in a finely divided colloidal condition and are of use as pigments, fillers for rubber, catalysts, adsorptive agents, bleaching materials, heat insulators, and emulsifiers. Specification 367,407 is referred to. The Specification as open to inspection under Sect. 91 (3) (a) relates to the use of metal carbonates generally and specifies the use of magnesium carbonate, hydrated magnesium carbonate, basic magnesium carbonate, and calcium carbonate in the above process, and the production of magnesium silicates which are decolourizing agents; this subject-matter does not appear in the Specification as accepted.ALSO:Finely divided colloidal metal silicates suitable as fillers for rubber are prepared by heating a stream of metal carbonate other than magnesium carbonate, silica and water under pressure to a temperature above the boiling-point of water until all the carbon dioxide has been evolved. Suitable siliceous material is diatomaceous earth, quartz, opaline silica, and suitable carbonates are those of barium, copper, iron and zinc. The Specification as open to inspection under Sect. 91 (3) (a) relates to the production of metal silicates generally and specifies the preparation of magnesium silicate; this subject-matter does not appear in the Specification as accepted.