The present disclosure discloses a method for graded utilization of fluorine and silicon resources in a phosphate ore. While the phosphate ore reacts with sulfuric acid, a fluorine-containing and silicon-containing tail gas is produced. SiO.sub.2 and H.sub.2SiF.sub.6 solution with a high concentration are obtained by concentrating and filtering a solution containing HF and H.sub.2SiF.sub.6 formed after tail gas is absorbed by water. Crude SiF.sub.4 and a solution containing HF and H.sub.2SO.sub.4 are obtained by extracting, adsorbing, and dehydrating the H.sub.2SiF.sub.6 solution. SiF.sub.4 with a 5N purity is obtained after the crude SiF.sub.4 is adsorbed and distilled, at the same time, an impurity-enriched SiF.sub.4 is returned to operations of concentration and filtration to react with the solution containing HF and H.sub.2SiF.sub.6 to generate the H.sub.2SiF.sub.6 and SiO.sub.2. High-purity HF and waste sulfuric acid are obtained after the H.sub.2SO.sub.4 solution containing HF is separated by steam stripping and distillation.

The present disclosure discloses a method for graded utilization of fluorine and silicon resources in a phosphate ore. While the phosphate ore reacts with sulfuric acid, a fluorine-containing and silicon-containing tail gas is produced. SiO.sub.2 and H.sub.2SiF.sub.6 solution with a high concentration are obtained by concentrating and filtering a solution containing HF and H.sub.2SiF.sub.6 formed after tail gas is absorbed by water. Crude SiF.sub.4 and a solution containing HF and H.sub.2SO.sub.4 are obtained by extracting, adsorbing, and dehydrating the H.sub.2SiF.sub.6 solution. SiF.sub.4 with a 5N purity is obtained after the crude SiF.sub.4 is adsorbed and distilled, at the same time, an impurity-enriched SiF.sub.4 is returned to operations of concentration and filtration to react with the solution containing HF and H.sub.2SiF.sub.6 to generate the H.sub.2SiF.sub.6 and SiO.sub.2. High-purity HF and waste sulfuric acid are obtained after the H.sub.2SO.sub.4 solution containing HF is separated by steam stripping and distillation.

In an aspect, provided herein are methods for producing sulfuric acid and hydrogen gas, the methods comprising steps of: providing sulfur dioxide formed by thermal conversion of a sulfur-containing species; electrochemically oxidizing said sulfur dioxide to sulfuric acid in the presence of water; and electrochemically forming hydrogen gas via a reduction reaction. In some embodiments, the methods comprise a step of thermally converting said sulfur-containing species to said sulfur dioxide. Systems configured to perform these methods are also disclosed herein. Also provided herein are methods and systems for producing sulfuric acid and hydrogen gas by electrochemically forming the sulfuric acid and the hydrogen gas in a mixture comprising a sulfur material, a supporting acid, and water. Also provided herein are methods and systems for producing a cement material.

In an aspect, provided herein are methods for producing sulfuric acid and hydrogen gas, the methods comprising steps of: providing sulfur dioxide formed by thermal conversion of a sulfur-containing species; electrochemically oxidizing said sulfur dioxide to sulfuric acid in the presence of water; and electrochemically forming hydrogen gas via a reduction reaction. In some embodiments, the methods comprise a step of thermally converting said sulfur-containing species to said sulfur dioxide. Systems configured to perform these methods are also disclosed herein. Also provided herein are methods and systems for producing sulfuric acid and hydrogen gas by electrochemically forming the sulfuric acid and the hydrogen gas in a mixture comprising a sulfur material, a supporting acid, and water. Also provided herein are methods and systems for producing a cement material.

The present invention concerns a method for recovering phosphorus by thermochemical reaction of a phosphorus-containing material such as an alternative fuel, for example, in the presence of calcium-containing particles in a moving bed reactor and subsequent separation of fines enriched with phosphorus from the moving bed reactor. Furthermore, the present invention concerns the use of a recyclable material obtained by the method as a fertilizer or fertilizer additive.

The present invention concerns a method for recovering phosphorus by thermochemical reaction of a phosphorus-containing material such as an alternative fuel, for example, in the presence of calcium-containing particles in a moving bed reactor and subsequent separation of fines enriched with phosphorus from the moving bed reactor. Furthermore, the present invention concerns the use of a recyclable material obtained by the method as a fertilizer or fertilizer additive.

A method for producing a cement material wherein 1) a first acid is reacted with a first cement precursor to form a second cement precursor, and 2) the second cement precursor is converted to a cement material. The first cement precursor includes one or more of Ca, Si, or Al, and the reaction with the first acid produces a second cement precursor that includes one or more of Ca, Si, or Al, and the conjugate base of the first acid. The second step can be performed by thermally converting the second cement precursor to a cement material by sintering or thermally decomposing the second cement precursor at a temperature in the range of 500 to 2000? C. The first step can be performed in the presence of water as a wet slurry. The concentration of the first acid can be greater than 20% by weight.

A method for producing a cement material wherein 1) a first acid is reacted with a first cement precursor to form a second cement precursor, and 2) the second cement precursor is converted to a cement material. The first cement precursor includes one or more of Ca, Si, or Al, and the reaction with the first acid produces a second cement precursor that includes one or more of Ca, Si, or Al, and the conjugate base of the first acid. The second step can be performed by thermally converting the second cement precursor to a cement material by sintering or thermally decomposing the second cement precursor at a temperature in the range of 500 to 2000? C. The first step can be performed in the presence of water as a wet slurry. The concentration of the first acid can be greater than 20% by weight.

The invention relates to a method for manufacturing an ammonium phosphate fertilizer from a phosphoric acid aqueous solution that has less than 50% P.sub.2O.sub.5 concentration and is obtained by wet phosphate ore treatment, said phosphoric acid containing traces of cadmium, comprising the following steps: (a) neutralizing said phosphoric acid solution (1) with ammonia (3) up to a molar ratio N/P of between 0.1 and 0.8, (b) reacting said partially neutralized solution (4) with a sulfide source (6) so as to form a cadmium sulfide precipitate (9), (c) separating said precipitate (9) so as to obtain a refined ammoniated phosphoric acid solution (10), (d) ammoniating and granulating said refined solution (10) so as to form said fertilizer (12).

A process and a process plant for conversion of SO.sub.2 to H.sub.2SO.sub.4 including a. directing a process gas stream including at least 15 vol % SO.sub.2, and an amount of O.sub.2 originating from a source of purified O.sub.2 or O.sub.2 enriched air to contact a first material catalytically active in oxidation of SO.sub.2 to SO.sub.3 under oxidation conditions involving a maximum steady state temperature of the catalytically active material above 700 C., to provide an oxidized process gas stream, wherein the material catalytically active in oxidation of SO.sub.2 to SO.sub.3 includes an active phase in which the weight ration of vanadium to other metals is at least 2:1 supported on a porous carrier comprising at least 25 wt % crystalline silica, b. absorbing at least an amount of the produced SO.sub.3 in a stream of lean sulfuric acid to provide a stream of liquid sulfuric acid.