Phosphoric Acid → Carbonate Ion

Participants

Reaction Steps

By the reaction of magnesium carbonate in an aqueous, 10-40% suspension with technical phosphoric acid at a molar ratio of 2:1 there is obtained magnesium hydrogen phosphate with a carbonate proportion of 50 mole-%. The reaction may be carried out at temperatures between room temperature and heat of boiling of the mixture, but it is carried out preferably, in the case of an amount of a few kilograms, at temperatures of from 30° to 50° C. for a period of time of 30 minutes, with the period of time, but also the temperature, depending upon the converted amount. In the case of a production charge of about 5 t, for instance, the temperature increases on account of the resultant heat of reaction to about 90° C., and the reaction lasts for about 3 hours. Hence, the duration of the reaction and the reaction temperature are the longer and higher, the larger the amount used is. The increase in temperature also has the advantageous effect that the time of reaction can be kept within reasonable limits. The precipitated pigments are filtered off in customary manner, manner, are dried at 105° C. and ground.

Provenance & Evidence