US 4,919,906 A · Processes and equipment for production of elemental phosphorus and thermal phosphoric acid

Abstract

New processes and equipment are disclosed for producing elemental phosphorus and thermal phosphoric acid. Benefits are listed below. 1. Phosphorus-containing solids are recycled to smelting furnaces thus eliminating hazardous waste generation. 2. Phosphorus furnace feedstock is upgraded and this permits unbeneficiated phosphate ore to be smelted. 3. Energy is conserved during manufacture of elemental phosphorus and phosphoric acid. 4. Electric energy is produced by cogeneration. 5. Fluorine in phosphate ore is recovered as ammonium fluoride. 6. Phosphorus-containing liquids are used as feedstock for production of suspension fertilizers. Benefits are achieved by agglomerating phosphate ore with monocalcium phosphate binder by a method which upgrades the ore. Phosphorus-containing solids are fluidized and burned to form an impure phosphoric acid mixture which is reacted with small sized phosphate ore to form monocalcium phosphate binder. Gases from agglomerator are scrubbed with condenser water to collect fluorine compounds. Scrubber effluent is treated with ammonia to convert fluosilicate compounds to ammonium fluoride and precipitate silica. Precipitate is added to agglomerator to provide SiO.sub.2 as flux to smelt phosphate ore. Surplus condenser water, containing ammonium fluoride and ammonium phosphate, is used to produce suspension fertilizers. Elemental phosphorus is burned to form P.sub.2 O.sub.5 which is hydrated with water to make phosphoric acid. Energy released by burning elemental phosphorus and by hydrating P.sub.2 O.sub.5 is recovered as electric energy. Byproduct furnace gas is cleaned and burned in a cogeneration facility to produce electric energy.

Claims34

Dependent claims

A process for production of elemental phosphorus, said process comprised of the following steps:

(a) agglomerating phosphate ore by tumbling with binder formed by reacting acidic phosphorus compounds with alkaline substances;
(b) smelting agglomerated phosphate ore in step (a) with reducing carbon and silica in a submerged-arc electric furnace to generate a mixture of gases, said gas mixture containing carbon monoxide, hydrogen, and elemental phosphorus;
(c) cooling gases in step (b) by contacting said gases with water;
(d) collecting mixture of elemental phosphorus, phosphorus-containing solids, and water from step (c) in a sump;
(e) recycling water from step (d) to step (c);
(f) bleeding off a stream of water from step (e);
(g) removing phosphorus-containing solids from stream of water bled off in step (f);
(h) pumping mixture of elemental phosphorus and phosphorus-containing solids from said sump in step (d) to a tank having submerged pump in a well;
(i) pumping bottom layer to product storage;
(j) pumping phosphorus-containing solids from step (g) and step (i) to fluidizer;
(k) fluidizing mixture of phosphorus-containing solids in step (j);
(l) feeding fluidized mixture from step (k) to a burner;
(m) oxidizing mixture from step (l) to form phosphorus oxides;
(n) reacting phosphorus oxides in step (m) with water to form acidic phosphorus compounds;
and
(o) pumping acidic phosphorus compounds in step (n) to step (a).

13 more elements

Process for production of solution containing ammonium fluoride, potassium fluoride, and ammonium phosphate, said process comprised of the following steps:

(a) agglomerating phosphate ore by tumbling with binder formed by reacting phosphoric acid with phosphate ore;
(b) drying agglomerated phosphate ore formed in step (a);
(c) smelting agglomerated phosphate ore in step (b) with reducing carbon and silica in a submerged-arc electric furnace to generate mixture of gases, said mixture containing carbon monoxide, hydrogen, and elemental phosphorus;
(d) cleaning gases generated in step (c) by treating said gases with an electrostatic precipitator;
(e) cooling gases generated in step (c) by contacting said gases with water;
(f) collecting mixture of elemental phosphorus, phosphorus-containing solids, and water from step (e) in a sump;
(g) recycling water from step (f) to step (e);
(h) bleeding off a stream of water from step (g);
(i) removing phosphorus-containing solids from stream of water bled off in step (h);
(j) recycling water from step (i) to step (f);
(k) bleeding off stream of recycled water in step (j);
(l) slurrying precipitator dust collected in step (d) with stream of recycled water in step (j);
(m) separating liquid nd solid phases in step (l);
(n) recycling liquid phase in step (m) to sump in step (f);
(o) ammoniating stream of recycled water in step (j) to prepare scrubbing medium;
(p) scrubbing gases discharging in step (a) and step (b) with scrubbing medium prepared in step (o);
(q) separating liquid and solid phases in scrubbing medium in step (p);
(r) adding phosphoric acid to liquid phase in step (q) to prepare scrubbing medium;
(s) scrubbing gases discharging in step (a) and step (b) with scrubbing medium prepared in step (r);
and
(t) collecting scrubbing medium from step (s) containing ammonium fluoride, potassium fluoride, and ammonium phosphate.

18 more elements

Process for generation of electric energy, said process comprised of the following steps:

(a) agglomerating phosphate ore by tumbling with a binder formed by reacting acidic phosphorus compounds with alkaline substances;
(b) smelting agglomerated phosphate ore in step (a) with reducing carbon and silica in a submerged-arc electric furnace to generate a mxiture of gases, said mixture containing carbon monoxide, hydrogen, and elemental phosphorus;
(c) cooling gases in step (b) by contacting said gases with water;
(d) collecting mixture of elemental phosphorus, phosphorus-containing solids, and water from step (c) in a sump;
(e) recycling water from step (d) to step (c);
(f) bleeding off a stream of water from step (e);
(g) removing phosphorus-containing solids from stream of water bled off in step (f);
(h) pumping mixture of elemental phosphorus and phosphorus-containing solids from said sump in step (d) to a tank having submerged pump in a well;
(i) pumping bottom layer to storage;
(j) pumping phosphorus-containing solids from step (g) and step (i) to fluidizer;
(k) fluidizing mixture of phosphorus-containing solids in step (j);
(l) feeding fluidized mixture from step (k) to phosphoric acid production unit;
(m) cooling phosphoric acid made in step (l) with boiler feedwater;
(n) recycling phosphoric acid in step (m) to phosphoric acid production unit;
(o) pumping phosphoric acid in step (m) to step (a);
(p) feeding elemental phosphorus from step (i) to phosphoric acid production unit;
(q) cooling combustion chamber, hydrator, phosphoric acid, and separator tower bottom with boiler feedwater;
(r) recycling cooled phosphoric acid to phosphoric acid production unit;
(s) feeding boiler feedwater from step (m) and step (q) to boiler;
(t) cleaning gases in step (c);
(u) burning gases from step (t) in boiler in step (s);
and
(v) generating electric energy from steam obtained in step (u).

20 more elements

Dependencies are inferred from the claim text.

Processes and equipment for production of elemental phosphorus and thermal phosphoric acid

Life of this patent

Processes and equipment for production of elemental phosphorus and thermal phosphoric acid

Life of this patent

Abstract

Claims34