Process for producing granular alkali metal nitrilotriacetate

Abstract

There is disclosed a process for preparing highly absorptive granular alkali metal nitrilotriacetate by contacting NTA powder with a partially neutralizing amount of acid. A granular product having a majority of the granules, by weight, in the -12 to +80 mesh size range, which have a density of at least about 0.70 g/cc and an absorptivity in the absorptivity test in the range of above 12 ml/100 g is produced by contacting alkali metal nitrilotriacetate with acid, mixing the material to granulate it and then drying the granules. The acid may be added in either one or two steps. In the one step embodiment the acid addition time/mix time ratio is critical while in the two addition step embodiment mix time is not critical. However, in the two step embodiment the powder is first contacted is with dilute acid and the second contact step is with concentrated acid. A granular product having a density of at least about 0.70 g/cc, fewer than 15% fine material and an absorptivity in the range of from about 12-14 ml/100 g is produced.

Dependencies are inferred from the claim text.