Method

Abstract

There is provided a method of producing a mixed metal compound that includes at least Mg 2+ and at least Fe 3+ having an aluminum 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 Mg 2+ salt and a Fe 3+ salt with Na 2 CO 3 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/m 3 (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.

1 . A method of producing a mixed metal compound comprising
 at least Mg 2+  and at least Fe 3+     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 Mg 2+  salt and a Fe 3+  salt with Na 2 CO 3  and NaOH to produce a slurry, wherein the pH of the slurry is maintained at from 9.5 to 11, and wherein the Na 2 CO 3  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/m 3    
 (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. 
 
   
     
     
         2 . A method according to  claim 1  wherein the compound is of the formula
   M II   1-x M III   x (OH) 2 A n−   y   .m H 2 O  (II)
 
 wherein M II  is one or more bivalent metals and is at least Mg 2+ ; 
 M III  is one or more trivalent metals and is at least Fe 3+ ; 
 A n−  is one or more n-valent anions and is at least CO 3   2− ; 
 x/Σyn is from 1 to 1.2 
 0<x≦0.4, 
 0<y≦1 and 
 0<m≦10. 
 
     
     
         3 . (canceled) 
     
     
         4 . (canceled) 
     
     
         5 . A method according to  claim 1  wherein the molar ratio of Mg 2+  to Fe 3+  is 2.5:1 to 1.5:1. 
     
     
         6 . A method according to  claim 1  wherein the compound has an average crystal size of from 10 to 20 nm (100 to 200 Å). 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . A method according to  claim 1  wherein the total sulphate content of the compound is from 1.8 to 4.2 wt %. 
     
     
         10 . A method according to  claim 1  wherein the interlayer sulphate content of the compound is from 2.1 to 5 wt %. 
     
     
         11 .- 20 . (canceled) 
     
     
         21 . A method according to  claim 1  wherein in step (b) the slurry conditions are controlled such that a d50 particle size distribution of at least 40 μm is provided. 
     
     
         22 . A method according to  claim 1  wherein in step (c) the mixed metal compound is separated from the slurry, to obtain a crude product having a dry solid content of at least 15 wt %. 
     
     
         23 .- 26 . (canceled) 
     
     
         27 . A method according to  claim 1  wherein in step (d) the crude product is dried to a moisture content less than 15 wt %. 
     
     
         28 .- 31 . (canceled) 
     
     
         32 . A method according to  claim 1  wherein the dried crude product is milled to a d50 average particle size of less than 200 μm. 
     
     
         33 .- 39 . (canceled) 
     
     
         40 . A method according to  claim 1  for the production of a mixed metal compound having a sodium content expressed as Na 2 O of less than 0.5 wt %. 
     
     
         41 . (canceled) 
     
     
         42 . A method according to  claim 1  for the production of a mixed metal compound having a phosphate binding capacity of more than 0.6 mmol phosphate/g mixed metal compound. 
     
     
         43 .- 47 . (canceled) 
     
     
         48 . A mixed metal compound comprising at least Mg 2+  and at least Fe 3+ , wherein
 the molar ratio of Mg 2+  to Fe 3+  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. 
 
     
     
         49 . A mixed metal compound according to  claim 48  wherein the d50 average particle size of the mixed metal compound is less than 200 μm. 
     
     
         50 .- 52 . (canceled) 
     
     
         53 . A mixed metal compound comprising at least Mg 2+  and at least Fe 3+ , wherein
 the molar ratio of Mg 2+  to Fe 3+  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 interlayer sulphate content of the compound is from 2 to 5 wt % 
 
     
     
         54 .- 63 . (canceled) 
     
     
         64 . A compound according to  claim 48  wherein the compound is of the formula
   M II   1-x M III   x (OH) 2 A n−   y   .m H 2 O 
 wherein M II  is one or more bivalent metals and is at least Mg 2+ ; 
 M III  is one or more trivalent metals and is at least Fe 3+ ; 
 A n−  is one or more n-valent anions and is at least CO 3   2− ; 
 x/Σyn is from 1 to 1.2 
 0<x≦0.4, 
 0<y≦1 and 
 0<m≦10. 
 
     
     
         65 .- 76 . (canceled) 
     
     
         77 . A mixed metal compound according to  claim 48  for use in the treatment of hyperphosphataemia. 
     
     
         78 . A pharmaceutical composition comprising a mixed metal compound as defined in  claim 48  and optionally one or more pharmaceutically acceptable adjuvants, excipients, diluents or carriers. 
     
     
         79 .- 82 . (canceled)