| 摘要 |
<p>Cement clinker is made by sintering with a calcium compound such as limestone, the insoluble residue left after leaching out sodium aluminate from a comminuted sinter produced by burning a compound of silica and alumina, e.g. kaolin, with calcium and sodium compounds, e.g. limestone and soda ash, and, if desired, a further aluminium compound, e.g. sodium aluminate. The materials may be ground more finely before the first sintering step than before the subsequent leaching. The leaching may be incomplete to leave some sodium aluminate in the insoluble residue, if a cement with a high alumina content is required. In both sintering steps the materials may be burnt dry, moist, or as a slurry. The insoluble residue from the first sintering may be treated with calcium chloride as described in U.S.A. Specification 1,964,685 to ensure removal of sodium.</p> |
