CALCIUM NITRATE Russian patent published in 2011 - IPC C01F11/36 

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of cleaning calcium nitrate solutions/melt and a calcium nitrate solution/melt obtained using the said method, and can be used in chemical industry. The method of cleaning solutions or melt of calcium nitrate involves the following steps: a) dissolving or diluting calcium nitrate solution/melt to concentration 1.3-1.75 kg/l at temperature 20-90°C, b) neutralising the obtained solution, c) adding a flocculant and correcting molar ratio of phosphorus to fluorine, d) precipitation, e) centrifuging the precipitated phase. At step (a) the melt is diluted to approximately 1.6 kg/l at 70°C. At step (c) molar ratio of phosphorus to fluorine is corrected to a value higher than 0.30, preferably higher than 0.45. Precipitation at step (d) is carried out in a separate tank which is fitted with think plates and lamellae. The calcium nitrate solution/melt which is cleaned using the said method contains less than 3% insoluble substances.

EFFECT: method enables to lower content of insoluble impurities in calcium nitrate to a value of 50-100 mln^-1 and lower power consumption at the step for cleaning calcium nitrate.

6 cl, 2 tbl, 7 dwg, 4 ex