Hard porous mouldings or pellets contg. crystalline silica - made from silica flour and guanidine silicate soln., and used esp. as catalysts or catalyst carriers

摘要

Silica flour is mixed with a soln. (I) of guanidine silicate and possibly with extra water. The mixt. is possibly predried, and is next moulded, dried and possibly also tempered. The silica flour is pref. 1-100 mu m, esp. 1-50 mu m, in size; whereas the aq. soln. (I) pref. has a wt. ratio of guanidine silicate:water of 1:2 to 4:1, esp. 1-2.6:1. The wt. ratio S/G, where S = SiO2 and G = guanadine silicate, is pref. 1.4-25/1, esp. 3-23/1. The total water content of the mixt. is pref. 3-50, esp. 4.4-30 wt.%. The mixt. may also contain 0-30%, esp. 1-23% addns. (II), esp. silica gel or powder or zeolites; or substances (II) low in alkali, esp. sawdust, cellulose-ether, active carbon or soot. The mouldings are employed esp. as catalysts or catalyst carriers with specific surface 1-30m2/g., and average pore widths 10-1000 nm, esp. contg. only 0.01-0.1% alkali calculated as Na2O.