| 摘要 |
<p>Clay is activated by mixing it with 25-60% by weight of water and 10-50% by weight of sulphuric acid and heating for a time and at a temperature sufficient to activate the clay and reduce the water content to a maximum of 10% by weight. This heating is preferably carried out for 10-250 minutes at a tempera <PICT:0856756/III/1> ture of 100-400 DEG C. The process may be carried out continuously by passing the mixture, preferably in the form of pellets, through a heating zone at 100-200 DEG C., the residence time in the zone being 10-40 minutes. The heating may be effected in a spouting bed column (Fig. 2) as described and claimed in Specification 801,315. In Fig. 2, a tower 1 contains a bed 2 of wet clay pellets. Air enters through an orifice 6, forming a narrow column 7 in which the pellets are moving upwards to form a spout 8, the pellets outside said column moving downwards and inwards towards said column. The activated clay leaves via pipe 4. The activated clay may be employed for bleaching oils. In an example, an unbleached hydrocarbon oil, namely a semi-finished solvent refined dewaxed mineral oil with viscosity corresponding to SAE No. 30 and a viscosity index of 90, was mixed with the clay and heated to 143 DEG C. in 15 minutes in a carbon dioxide atmosphere, after which the mixture was cooled to 100 DEG C. and filtered.</p> |
