Processes of making monohydrate form of magnesium ammonium phosphate and processes of making cigarette paper using same

Abstract

Processes for producing the monohydrate form of magnesium ammonium phosphate in slurry from use of environmentally friendly reactants are described. Slurry containing the monohydrate form of magnesium ammonium phosphate can be fed directly to, and mixed with, paper making feedstock, such as feedstock for cigarette paper, without transformation of the monohydrate form to the hexahydrate form of magnesium ammonium phosphate.

1 . A process of making a slurry, comprising: 
 introducing at least magnesium, phosphate and nitrogen into a vessel by introducing at least two reactants into the vessel;    reacting the at least two reactants to produce a slurry comprising substantially dittmarite; and    maintaining the slurry at a sufficiently high temperature to substantially prevent the transformation of the dittmarite to struvite.    
   
   
       2 . The process of  claim 1 , wherein the slurry comprises a solids portion including at least 95 wt. % dittmarite.  
   
   
       3 . The process of  claim 1 , wherein the at least two reactants include (i) ammonium dihydrogen phosphate and (ii) at least one of magnesium hydroxide and magnesium oxide.  
   
   
       4 . The process of  claim 1 , wherein ammonium dihydrogen phosphate is introduced into the vessel as an aqueous solution, and at least one of magnesium hydroxide and magnesium oxide is introduced into the vessel as a slurry having a solids content below 30 wt. %.  
   
   
       5 . The process of  claim 1 , wherein the at least two reactants include ammonium dihydrogen phosphate and magnesium acetate.  
   
   
       6 . The process of  claim 1 , wherein the slurry has a solids content no greater than 20 wt. %.  
   
   
       7 . The process of  claim 1 , wherein the vessel is sealed.  
   
   
       8 . The process of  claim 1 , further comprising drying the slurry.  
   
   
       9 . The process of  claim 8 , wherein the drying is conducted with a spin-flash drier.  
   
   
       10 . The process of  claim 1 , wherein the vessel is maintained at a temperature of at least about 100° C.  
   
   
       11 . A process of making paper, comprising: 
 producing a slurry comprising substantially dittmarite by the process according to  claim 1;  and    combining the slurry with paper making feedstock in a paper making process.    
   
   
       12 . The process of  claim 11 , further comprising reducing particle size of the dittmarite before combining the slurry with the paper making feedstock.  
   
   
       13 . The process of  claim 11 , further comprising drying the slurry and then reslurrying dried dittmarite before combining the slurry with the paper making feedstock.  
   
   
       14 . The process of  claim 11 , wherein the slurry is fed directly from the vessel to the paper making process without transformation of the dittmarite to the hexahydrate form of magnesium ammonium phosphate.  
   
   
       15 . The process of  claim 11 , wherein the slurry is maintained at a temperature above a phase transition temperature of dittmarite to a hexahydrate form of the magnesium ammonium phosphate from when the slurry is produced until the slurry is combined with the paper making feedstock.  
   
   
       16 . The process of  claim 15 , wherein the slurry is maintained at a temperature of at least about 60° C. from when the slurry is produced until the slurry is combined with the paper making feedstock.  
   
   
       17 . The process of  claim 16 , further comprising heating the slurry to a temperature of at least about 60° C. in the vessel.  
   
   
       18 . The process of  claim 11 , wherein the paper making process is a cigarette paper making process.  
   
   
       19 . A process of making a slurry, comprising: 
 introducing at least magnesium, phosphorous and nitrogen into a vessel by introducing at least two reactants into the vessel, the at least two reactants not including phosphoric acid;    reacting the at least two reactants to produce a slurry comprising substantially dittmarite; and    maintaining the slurry at a sufficiently high temperature to substantially prevent the transformation of the dittmarite to struvite.    
   
   
       20 . The process of  claim 19 , wherein the slurry comprises a solids portion including at least 95 wt. % dittmarite.  
   
   
       21 . The process of  claim 19 , wherein the slurry has a solids content no greater than 20 wt. %.  
   
   
       22 . The process of  claim 19 , further comprising drying the slurry.  
   
   
       23 . The process of  claim 19 , wherein the vessel is maintained at a temperature of at least about 100° C.  
   
   
       24 . A process of making paper, comprising: 
 producing a slurry comprising substantially dittmarite by the process according to  claim 19;  and    combining the slurry with paper making feedstock in a paper making process.    
   
   
       25 . The process of  claim 24 , further comprising reducing particle size of the dittmarite before combining the slurry with the paper making feedstock.  
   
   
       26 . The process of  claim 24 , further comprising drying the slurry and then reslurrying dried dittmarite before combining the slurry with the paper making feedstock.  
   
   
       27 . The process of  claim 24 , wherein the slurry is fed directly from the vessel to the paper making process without transformation of the dittmarite to the hexahydrate form of magnesium ammonium phosphate.  
   
   
       28 . The process of  claim 24 , wherein the slurry is maintained at a temperature above a phase transition temperature of dittmarite to a hexahydrate form of the magnesium ammonium phosphate from when the slurry is produced until the slurry is combined with the paper making feedstock.  
   
   
       29 . The process of  claim 24 , wherein the paper making process is a cigarette paper making process.