| 摘要 |
FIELD: chemical industry, inorganic chemistry. ^ SUBSTANCE: method involves dissolving an ammonium nitrate sample followed by complexometric titration of calcium ions with Trilon B with indicator chrome dark-blue at pH = 9.5-10.0 provided by ammonium buffer solution. Ethyl alcohol is used as a solvent in the mass ratio of sample to ethyl alcohol = 2:39.45. The separation of analyzed components is carried out on the basis of their different solubility in ethyl alcohol wherein Ca(NO3)2 exhibits good solubility but CaSO4 is insoluble practically. The precipitate of alcohol-insoluble calcium sulfate is separated by filtration, dissolved in hydrochloric acid and calcium sulfate is determined in hydrochloric acid solution and calcium nitrate is determined in alcoholic filtrate. Invention shows high precision and provides separate assay of calcium sulfate and calcium nitrate in ammonium nitrate of enhanced strength with dolomite-sulfate additive. ^ EFFECT: improved assay method. ^ 4 tbl |
