Methods for the continuous polymerization of phosphate compounds to form polyphosphate compositions

A process for producing a polyphosphate composition, the process comprising:

• (a) continuously introducing a phosphate compound into a polymerization vessel, the phosphate compound comprising melamine magnesium phosphate and/or melamine zinc phosphate;
• (b) polymerizing the phosphate compound at a temperature in a range from about 250 to about 450° C. for a time period sufficient to form the polyphosphate composition;
• and
• (c) continuously discharging the polyphosphate composition from the polymerization vessel, wherein the polyphosphate composition comprises:
• from about 15 wt. % to about 60 wt. % of a polyphosphate, the polyphosphate comprising a melamine poly(magnesium phosphate) and/or a melamine poly(zinc phosphate);
• less than or equal to about 15 wt. % of the phosphate compound;
• and
• from about 35 wt. % to about 80 wt. % of a pyrophosphate compound.

A process for producing a polyphosphate composition, the process comprising:

• (a) continuously introducing a phosphate compound into a polymerization vessel, wherein:
• the phosphate compound comprises melamine phosphate;
• and
• the polymerization vessel is a rotary kiln, a vertical kiln, or a spiral kiln;
• (b) polymerizing the phosphate compound at a temperature in a range from about 250 to about 450° C. for a time period sufficient to form the polyphosphate composition;
• and
• (c) continuously discharging the polyphosphate composition from the polymerization vessel, wherein the polyphosphate composition comprises:
• from about 15 wt. % to about 60 wt. % of a polyphosphate, the polyphosphate comprising a melamine polyphosphate;
• less than or equal to about 20 wt. % of the phosphate compound;
• and
• from about 35 wt. % to about 80 wt. % of a pyrophosphate compound.