Process for surface modification of particulate solids

摘要

Improved utilization of organosilicon compounds in hydrophobicizing finely divided particulate solids is accomplished by metering a partial amount of unreacted solids with organosilicon containing offgases derived from admixing and reacting a major portion of solids with organosilicon compounds and admixing the offgas-treated solids with the major portion of solids to be treated.

主权项

1. A process for producing surface modified particulate finely divided solid F having a BET surface area of from 0.1 m2/g to 1000 m2/g, comprising the steps of:
(A) mixing a first amount of unmodified finely divided solid F1 with organosilicon compound(s) to form a first mixture of F1 and organosilicon compound(s) and producing an offgas comprising organosilicon compound(s); (B) reacting the mixture of unmodified finely divided solid F1 with organosilicon compound(s) to produce surface modified finely divided solid F with or without an offgas comprising organosilicon compound(s); (C) freeing the surface modified finely divided solid F from step (B) of adsorbed byproducts and unconverted organosilicon compound(s) which are obtained as offgas; (D) metering a second amount of unmodified finely divided solid F1 into the offgas obtained in process steps (A), (C) or (B) putting in upstream of a filter to mix the solid F1 with organosilicon compound(s) in the offgas to form a second mixture of F1 and organosilicon compound(s); and (E) feeding the second mixture obtained in process step (D) to process step (A) to augment the first mixture of unmodified finely divided solid F1 and organosilicon compound(s).