W. R. Grace Co.

James R Hart

Felix B Popper

Jeremiah B McCarthy

An aqueous solution of a chelate of: (a) at least one metal selected from a first group consisting of: (i) magnesium; (ii) calcium; (iii) zinc; and (iv) manganese (II); and (b) at least one chelating agent selected from a second group consisting of moieties of: (i) ethylenediaminetetraacetic acid; (ii) nitrilotriacetic acid; (iii) diethylenetriaminepentaacetic acid; and (iv) hydroxyethylethylenediaminetriacetic acid is prepared by a process comprising forming a first admixture by admixing in an aqueous system an oxide or hydroxide of at least one member of the first group and at least one member selected from a third group consisting of a tetraalkali metal salt of ethylenediaminetetraacetic acid, a trialkali metal salt of nitrilotriacetic acid, a pentaalkali metal salt of diethylenetriaminepentaacetic acid, and a trialkali metal salt of hydroxyethylethylenediaminetriacetic acid; forming a second admixture by admixing the first admixture and a nitrile selected from a fourth group consisting of ethylenediaminetetraacetonitrile, nitrilotriacetonitrile, and diethylenetriaminepentaacetonitrile, and heating the second admixture to form the chelate and evaporate by-product ammonia therefrom, the pH of the resulting substantially ammonia-free product can then be adjusted to about 5-9.5 or preferably 6-9 if it is not already within this pH range.

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Merrimack, NH, United States of America

James R Hart