SPECTROPHOTOMETRIC METHOD FOR CADMIUM DET ERMINATION IN PHOSPHATE ROCK

The cadmium content in the phosphate rock is spectrophotometrically de termined with Cadion. The phosphate rock sample is treated with hydroc hloric acid, brought to the humid salts state (almost dry) and the res idue is dissolved in 2N hydrochloric acid. The cadmium determination i n the solution thus got does not require a previous separation, the in terfering ions being masked with an ascorbic acid - sodium and potassi um tartrate - sodium fluoride and potassium cyanide solution. The cadm ium is then unmasked with a formaline solution, its absorbance being m easured at 480 nm.