US 9,314,481 B2 · Method

Abstract

There is provided a method of producing a mixed metal compound comprising at least Mg2+ and at least Fe+ having an aluminium content of less than 10000 ppm, having an average crystal size of less than 20 nm (200 A) comprising the steps of: (a) combining a Mg2+ salt and a Fe3+ salt with Na2CO3 and NaOH to produce a slurry, wherein the pH of the slurry is maintained at from 9 5 to 1 1, and wherein the Na2CO3 is provided at an excess of 0 to 4.0 moles than is required to complete the reaction (b) subjecting the slurry to mixing under conditions providing a power per unit volume of 0 03 to 1.6 kW/m3 (c) separating the mixed metal compound from the slurry, to obtain a crude product having a dry solid content of at least 10 wt % (d) drying the crude product either by (i) heating the crude product to a temperature of no greater than 150° C. and sufficient to provide a water evaporation rate of 0.05 to 1 5 kg water per hour per kg of dry product, or (H) exposing the crude product to rapid drying at a water evaporation rate of 500 to 50000 kg water per hour per kg of dry product.

Claims25

Dependent claims

A method of producing a mixed metal compound comprising

at least Mg2+ and at least Fe3+
having an aluminium content of less than 10000 ppm,
having an average crystal size of less than 20 nm (200 Å)
comprising the steps of:
(a) combining a Mg2+ salt and a Fe3+ salt with Na2CO3 and NaOH to produce a slurry, wherein the pH of the slurry is maintained at from 9.5 to 11, and wherein the Na2CO3 is provided at an excess of 0 to 4.0 moles than is required to complete the reaction
(b) subjecting the slurry to mixing under conditions providing a power per unit volume of 0.03 to 1.6 kW/m3
(c) separating the mixed metal compound from the slurry, to obtain a crude product having a dry solid content of at least 10 wt %
(d) drying the crude product either by
(i) heating the crude product to a temperature of no greater than 150° C. and sufficient to provide a water evaporation rate of 0.05 to 1.5 kg water per hour per kg of dry product, or
(ii) exposing the crude product to rapid drying at a water evaporation rate of 500 to 50000 kg water per hour per kg of dry product.

7 more elements

A method of producing a mixed metal compound comprising

at least Mg2+ and at least Fe3+
having an aluminium content of less than 10000 ppm,
having an average crystal size of less than 20 nm (200 Å);
the method comprising the step of:
(a) combining a Mg2+ salt and a Fe3+ salt with Na2CO3 and NaOH to produce a slurry, wherein the slurry is maintained to a temperature between 15 and 30° C., and:
(i) wherein the pH of the slurry is maintained at from 9.5 to less than 9.8, and wherein the Na2CO3 is provided at an excess of greater than 1.0 to no greater than 5.0 moles than is required to complete the reaction;
or
(ii) wherein the pH of the slurry is maintained at from 9.5 to less than 10, and wherein the Na2CO3 is provided at an excess of greater than 1.0 to no greater than 4.0 moles than is required to complete the reaction;
or
(iii) wherein the pH of the slurry is maintained at from 9.5 to no greater than 10.1, and wherein the Na2CO3 is provided at an excess of greater than 1.0 to no greater than 2.7 moles than is required to complete the reaction;
or
(iv) wherein the pH of the slurry is maintained at from 9.5 to 10.5, and wherein the Na2CO3 is provided at an excess of from greater than 1.0 to no greater than 2.0 moles than is required to complete the reaction;
or
(v) wherein the pH of the slurry is maintained at from greater than 9.5 to no greater than 11, and wherein the Na2CO3 is provided at an excess of from 0.0 to no greater than 1.0 moles than is required to complete the reaction;
or the method comprising the step of:
(b) combining a Mg2+ salt and a Fe3+ salt with Na2CO3 and NaOH to produce a slurry, wherein the slurry is maintained to a temperature from 30 to 60° C., and:
(i) wherein the pH of the slurry is maintained at from greater than 9.5 to less than 11, and wherein the Na2CO3 is provided at an excess of greater than 0 to less than 2 moles than is required to complete the reaction;
or
(ii) wherein the pH of the slurry is maintained at from greater than 9.5 to less than 10.5, and wherein the Na2CO3 is provided at an excess of greater than 0 to less than 2.7 moles than is required to complete the reaction;
or
(iii) wherein the pH of the slurry is maintained at from greater than 9.5 to less than 10, and wherein the Na2CO3 is provided at an excess of greater than 0 to less than 4 moles than is required to complete the reaction.

18 more elements

Dependencies are inferred from the claim text.

Method

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Method

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Abstract

Claims25