Adsorbents, esp. for oils and fats - prepd. by hydrophobising a sintered mixt. of silica, clay and blowing agent

摘要

New porous adsorbents are prods. produced by (a) forming an aq. slurry contg. silica, clay and a blowing agent which burns at a temp. no higher than the sintering temp. of the silica and clay, (b) shaping and drying the slurry, (c) sintering the shaped material, and (d) hydrophobising the sintered product. The clay pref. has a SiO /Al2O3 ratio of 3 or less. A pref. clay (I) contains 40.0 wt.% SiO2, 40.0 wt.% Al2O3, 0.8-0.9 wt.% Fe2O3, 0.7 wt. CaO and 0.55 wt.% MgO (LOI equals 12.0%). The blowing agent is pref. sawdust. The slurry pref. contains 35-65 (esp. 50) pts.wt. silica, 35-65 (esp. 50) pts.wt. clay, 100-140 (esp. 100) pts.wt. sawdust and 300-450 pts.wt. water. Sintering is pref. effected at 1300-1400 deg.C. The prod., can be hydrophobised with a silicone-based water repellant. The adsorbents are esp. useful for cleaning up oil spills on water. They are inexpensive to produce, have a higher adsorptive capacity for heavy oils than hydrophobised perlite, and can be regenerated.