| 摘要 |
<p>515,601. Concentrating ores; cements. SMIDTH & CO AKTIESELSKABET F. L. June 20, 1938, No. 18281. [Class 82 (ii)] [Also in Groups III and V] The separation of minerals from argillaceous ores is effected by froth flotation in an aqueous pulp to which is added as depressing agent a lignin sulphonate, e.g., calcium or sodium lignin sulphonate, preferably in conjunction with an alkaline substance such as soda ash. The tailings from the froth flotation process may be dispersed with lignin sulphonate and concentrated by further froth flotation or by hydraulic classification in a classifier or, preferably, on a concentrating table. The process is applicable to argillaceous limestones. marls, chalks, &c. and phosphate ores, particularly where the ore has to be ground very finely to liberate the constituent minerals; a particular application is to remove sufficient of certain consitutents of the ores to render the residue suitable for cement manufacture. A calcite ore may be dispersed with a lignin sulphonate and alkali and then subjected to stage froth flotation using as a collecting agent saponified tall oil, as described in Specification 478,275, or emulsions of oleic acid or high melting point fatty acids such as fish oil acids. particularly the stabilized emulsions described in Specification 515,606: the frothing may be controlled by addition of a frothing agent such as cresylic acid or a mixture of branched and straight chain aliphatic monohydric alcohols, obtained, with methanol, by the catalytic hydrogenation of carbon oxides. Reflocculation of the tailings may be prevented by a further addition of a lignin sulphonate, and aluminium and magnesium silicates separated from the tailings by hydraulic means or by froth flotation using a flotation agent giving in solution a positive ion with a long-chain group, e.g. dodecyl amine hydrochloride. as described in Specification 515,608. The remainder of the tailings may then be added to the flotation concentrates to give a raw material for cement manufacture. Alternatively the cement raw material may be obtained by conditioning a pulp of the calcite ore with the dispersing agent and then subjecting it to stage flotation with a positive ion reagent to remove the aluminium silicates as described in Specification 515,609. Specification 426,423 also is referred to.</p> |
