Patent ID: 6051202
Filing Date: 2000-04-18
Classification: C01B,Y10S

Abstract:
A process for preparing far-infrared radiating material comprising the steps of:(a) mixing a solution of aluminum chloride with a soluble silicic acid-containing material to form an aluminum silicate gel;(b) adding a suspension of alkali earth-metal hydroxides to said aluminum silicate gel to form a calcium and magnesium salt of aluminum silicate in which the molar ratio of SiO.sub.2 plus Al.sub.2 O.sub.3 to CaO plus MgO is in the range 0.5 to 1.5/1;(c) aging the resulting first mixture by heating and agitating;(d) neutralizing a second mixture of a solution of sodium aluminate and a soluble silicic acid-containing material by adding hydrochloric acid to form an aluminum silicate gel;(e) mixing said aged first mixture with said aluminum silicate gel of step (d) while heating and agitating so as to form an ultra-fine aluminum silicate salt with a molar ratio in the range of 1.5 to 3.5/1 for SiO.sub.2 plus Al.sub.2 O.sub.3 to CaO plus MgO, a molar ratio in the range of 0.1 to 1.0/1 for Al.sub.2 O.sub.3 to SiO.sub.2, a molar ratio in the range of 0.1 to 0.5/1 for MgO to CaO, and a BET specific surface area of not less than 400 m.sup.2 /g;(f) mixing a soluble silicic acid-containing material with hydrochloric acid to produce a silicate gel;(g) adding 5 to 10 parts by weight of said silicate gel of step (f) to 100 parts by weight of said ultra-fine aluminum silicate salt;(h) adding AlCl.sub.3, FeCl.sub.2, and MnCl.sub.2 to the mixture at a total amount of 10 to 50 parts by weight per 100 parts by weight of said ultra-fine aluminum silicate salt; so as to have molar ratios in the range of 1/0.2 to 0.5 for Al.sub.2 O.sub.3 to FeO plus MnO, and 1/0.5 to 1.5 for FeO to MnO; and(i) neutralizing the resulting mixture with an ammonia solution.