PROCESS FOR THE PREPARATION OF PURE MAGNESIUM OXIDE, ESPECIALLY SUITABLE FOR THE PREPARATION OF FIRE RESISTANT PRODUCTS

摘要

PCT No. PCT/AT88/00048 Sec. 371 Date Feb. 27, 1989 Sec. 102(e) Date Feb. 27, 1989 PCT Filed Jun. 23, 1988 PCT Pub. No. WO88/10236 PCT Pub. Date Dec. 29, 1988.A process for the preparation of pure magnesium oxide, especially suitable for the preparation of refractory products, from magnesium silicate and magnesium hydrosilicate materials such as olivine, serpentine, garnierite, or the like, the starting material being decomposed (digested) with hydrochloric acid, the residues being separated from the decomposition slurry and the sesquioxides to be regarded as contaminants and other contaminants being precipitated from the crude brine thus obtained by the addition of crude serpentine as a pH increasing substance, the precipitates being separated and the magnesium chloride solution thus obtained being subjected to thermal decomposition, particularly by spray calcination, whereby magnesium oxide is obtained and hydrogen chloride is recovered.