Mixed metal compound

摘要

There is provided a method of producing a mixed metal compound comprising at least Mg2+ and at least Fe3+ having an aluminum 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.

主权项

1. A mixed metal compound comprising at least Mg2+ and at least Fe3+,
wherein the molar ratio of Mg2+ to Fe3+ is 2.5:1 to 1.5:1, the mixed metal compound has an aluminium content of less than 10000 ppm, the average crystal size of the mixed metal compound is from 10 to 20 nm (100 to 200 Å), and the d50 average particle size of the mixed metal compound is less than 300 μm.