A method and equipment for producing polyphosphoric acid from wet-process phosphoric acid

Abstract

The invention belongs to the technical field of phosphoric acid production in the inorganic chemical industry, and relates to a new production method and equipment for producing polyphosphoric acid from wet-process phosphoric acid. The innovation of this method mainly adopts a reverberatory furnace, plus burners, polyphosphoric acid tanks, oligophosphoric acid circulation pumps, smoke exhaust fans, packing washing towers, multiple control valves and other equipment, and uses wet-process phosphoric acid as raw material to concentrate and polymerize to produce polyphosphoric acid. phosphoric acid. The reaction equipment is reliable and stable, and the operation and control are simple and convenient, which solves the problem that the tubes and tubes of the tube and tube heat exchanger in the single-stage or multi-stage evaporation of wet-process phosphoric acid at home and abroad are easy to foul and difficult to deal with; the temperature control is moderate, avoiding local overheating and When the temperature is too high, the acid particles are carried away in large quantities; there is no need to use vacuum, which saves energy; the use of two-stage product output facilitates the improvement of production efficiency; the exhaust gas is recycled and used as raw materials after the washing liquid is recycled, which improves the product yield and reduces It reduces exhaust emissions and is conducive to environmental protection.

Description

technical field [0001] The invention belongs to the technical field of phosphoric acid production in the inorganic chemical industry, and relates to a method and equipment for producing polyphosphoric acid from wet-process phosphoric acid. Background technique [0002] Polyphosphoric acid is a fine phosphorus chemical product, and its main components are orthophosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid and high polyphosphoric acid. Molecular formula: H (n+2) P n o (3n+1) ; [0003] Structural formula: [0004] Typical product molecular formula: H 6 P 4 o 13 . The phosphoric acid content of polyphosphoric acid is generally 105-115%H 3 PO 4 . Polyphosphoric acid has low viscosity and freezing point, less corrosion, and has a good chelating effect on metal ions. It is mainly used in petrochemical condensation catalysts, dehydrating agents, metal surface treatment agents, analytical reagents, pharmaceuticals, organic Synth...

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Problems solved by technology

[0012] In order to solve the problems of difficult purification, high energy consumption, high temperature, easy overheating, easy precipitation, and easy corrosion of equipment in the process of producing polyphosphoric acid from wet-process phosphoric acid at home and abroad, a reverberatory furnace was invented to produce wet-process phosphoric acid. polyphosphoric acid

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