Method for making polyphosphoric acid

A method for consuming by-product phosphoric acid and reclaiming phosphorus values from the by-product phosphoric acid, said by-product phosphoric acid comprising phosphoric acid and one or more organic contaminants and said method comprising:

• (a) providing a packed column, said packed column extending from a bottom end to a top end and having one or more first inlet openings located at or near the top end of the column and one or more second inlet openings located below the first inlet openings;
• (b) introducing a first acid feed stream, said first acid feed stream comprising phosphoric acid, into the column at one or more of the first inlet openings;
• (c) introducing a second acid feed stream, said second acid feed stream comprising by-product phosphoric acid, into a stream of hot air to form a stream of hot air and acid;
• (d) introducing the stream of hot air and acid into the column at one or more of the second inlet openings;
• and
• (e) polymerizing phosphoric acid of the first and second feed streams to make polyphosphoric acid, while simultaneously decomposing the one or more organic contaminants.

A method for making polyphosphoric acid from phosphoric acid, comprising:

• (a) providing a packed column having a top end and a bottom end;
• (b) introducing a first acid feed stream, said first acid stream comprising phosphoric acid, into the top end of the column;
• (c) introducing a second acid feed stream, said second acid feed stream comprising phosphoric acid, into a stream of hot air to form a stream of hot air and acid;
• (d) introducing the stream of hot air and acid into the bottom end of the column;
• and
• (e) polymerizing phosphoric acid of the first and second acid feed streams to make polyphosphoric acid.

A method for consuming by-product phosphoric acid and reclaiming phosphorus values from the by-product phosphoric acid, said by-product phosphoric acid comprising phosphoric acid and organic contaminants, comprising:

• (a) providing a packed column having a top end and a bottom end;
• (b) introducing a first acid feed stream, said first acid feed stream comprising phosphoric acid, into the top end of the column;
• (c) introducing a second acid feed stream, said second acid feed stream comprising by-product phosphoric acid, into a stream of hot air to form a stream of hot air and acid;
• (d) introducing the stream of hot air and acid into the bottom end of the column;
• and
• (e) polymerizing phosphoric acid of the first and second feed streams to make polyphosphoric acid, while simultaneously decomposing the organic contaminants.