superˈphosphate
[super- 12 b.]
1. Chem. A phosphate containing an excess of phosphoric acid; an acid phosphate.
| 1797 Pearson in Phil. Trans. LXXXVIII. 17 It was..Scheele who discovered, that the urine of healthy persons contains superphosphate, or acidulous phosphate, of lime. 1811 A. T. Thomson Lond. Disp. (1818) 479 By the strong acids it [phosphate of soda] is converted into superphosphate of soda. 1876 Harley Royle's Mat. Med. (ed. 6) 62 When the superphosphate is heated with charcoal, tribasic phosphate is re-formed, and phosphoric acid set free. |
2. In full superphosphate of lime: an impure superphosphate of lime prepared by treating bones, coprolites, etc. with sulphuric acid, and used as a manure.
| 1843 W. Hay in Farmer's Mag. Jan. 42/2 By the action of sulphuric acid on bones a superphosphate of lime is produced. 1861 Times 10 Oct., Swedes, manured and sown with guano and superphosphate. 1868 Rep. U.S. Commissioner Agric. (1869) 221 A hundred and fifty to a hundred and seventy-five pounds of superphosphate strewn in the furrows to be ridged over. 1879 Cassell's Techn. Educ. II. 198/2 Mineral superphosphate is prepared by pouring sulphuric acid..on phosphorite or coprolites. |