| 摘要 |
<p>In the manufacture of bricks and earthenware articles (see Group V), a mixture of clay and ground oil shale, containing up to 70 per cent. of shale, is pressed to shape and heated to drive off the hydrocarbons which are withdrawn, mixed with air, and brought into contact with similar gases, unmixed with air, from other kilns to cause a deposition of sulphur. The residual gases are condensed in a tank.ALSO:Bricks and earthenware articles are prepared by heating shapes formed of a mixture of clay and oil shale so as to evaporate light hydrocarbons which are extracted, and then continuing to heat the shapes to produce the finished articles. The mixture of clay and ground oil shale containing up to 70 per cent. of oil shale, together, if desired, with up to one-third of the weight of the other materials of kieselguhr to produce a lighter article, is pressed into shape and the shapes are placed in a kiln having openings in the floor which may be covered or uncovered from outside. The kiln is fired with the openings covered, and the hydrocarbons driven off are extracted by a fan, purified, and condensed, (see Group III), any residual vapour being led back to the kiln to assist in the firing. The floor openings are then uncovered and the flames are thus permitted to enter the kiln and ignite any oil remaining in the shapes to facilitate burning and to produce a porous article. In an alternative process, the preliminary heating may be effected by steam-heated pipes.</p> |
