In the manufacture of phosphoric acid from ore, the typical ore comprises minerals containing phosphorus and calcium along with varied amounts of other elements. Certain ores have substantial iron content which needs to be removed in order to produce quality phosphoric acid product. An improved method and associated chemical processing plant are disclosed for removing this iron. The method involves both reducing and adding oxalic acid to wet process phosphoric acid produced using an otherwise conventional manufacturing process. Iron oxalate precipitate is created which can then conveniently be separated therefrom.

A method for reducing formation of scale in phosphoric acid production is provided herein. Phosphate-containing ore is combined with an acid to form an acidic slurry and the acidic slurry is processed to form an acidic stream. The method includes providing a scale inhibitor including an inorganic phosphate. The method further includes combining the scale inhibitor and at least one of the phosphate-containing ore, the acidic slurry, and the acidic stream, to reduce the formation of scale. A system for phosphoric acid production exhibiting a reduced formation of scale is also provided herein. The system includes a substrate having a surface in contact with at least one of the phosphate-containing ore, the acidic slurry formed from the phosphate-containing ore and the acid, and the acidic stream formed from the acidic slurry. The system including the scale inhibitor exhibits a reduced formation of scale on the surface.

Provided is a method for producing phosphoric acid and at the same time obtaining alpha-hemihydrate gypsum including: adding a phosphate rock powder and a part of dilute sulfuric acid into an extraction tank, carrying out an extraction reaction on same, separating a clear liquid from the obtained mixed slurry, sending the clear liquid, as a finished product phosphoric acid, into an acid storeroom, and transferring a separated solid, together with the rest mixed slurry, into a crystal transformation tank; and adding sulfuric acid and a crystal transformation agent into the crystal transformation tank, carrying out a crystal transformation reaction for 1.5-7.5 h at 60 C.-130 C., and solid-liquid separating the obtained mixed acid slurry, wherein the solid can be dried into a gypsum powder, or may be not subjected to a drying step and made into gypsum products such as gypsum boards, gypsum building blocks and gypsum members by directly adding water.

Provided herein are systems and methods for producing nitrophosphates and mineralized carbon. Advantageously, the systems and methods are capable of sequestering carbon from the atmosphere. The systems generally include a first reactor for producing nitric acid; a mixer for mixing the nitric acid produced in the first reactor with a phosphate source, thereby producing nitro-phosphoric acid; and a second reactor for producing a solution comprising nitrophosphates and mineralized carbon, wherein the second reactor is operable to receive: the nitro-phosphoric acid from the mixer, ammonia, water, and carbon dioxide.

A method for reducing formation of scale in phosphoric acid production is provided herein. Phosphate-containing ore is combined with an acid to form an acidic slurry and the acidic slurry is processed to form an acidic stream. The method includes providing a scale inhibitor including an inorganic phosphate. The method further includes combining the scale inhibitor and at least one of the phosphate-containing ore, the acidic slurry, and the acidic stream, to reduce the formation of scale. A system for phosphoric acid production exhibiting a reduced formation of scale is also provided herein. The system includes a substrate having a surface in contact with at least one of the phosphate-containing ore, the acidic slurry formed from the phosphate-containing ore and the acid, and the acidic stream formed from the acidic slurry. The system including the scale inhibitor exhibits a reduced formation of scale on the surface.

Provided herein are systems and methods for producing nitrophosphates and mineralized carbon. Advantageously, the systems and methods are capable of sequestering carbon from the atmosphere. The systems generally include a first reactor for producing nitric acid; a mixer for mixing the nitric acid produced in the first reactor with a phosphate source, thereby producing nitro-phosphoric acid; and a second reactor for producing a solution comprising nitrophosphates and mineralized carbon, wherein the second reactor is operable to receive: the nitro-phosphoric acid from the mixer, ammonia, water, and carbon dioxide.

Provided is a method for producing phosphoric acid and at the same time obtaining alpha-hemihydrate gypsum including: adding a phosphate rock powder and a part of dilute sulfuric acid into an extraction tank, carrying out an extraction reaction on same, separating a clear liquid from the obtained mixed slurry, sending the clear liquid, as a finished product phosphoric acid, into an acid storeroom, and transferring a separated solid, together with the rest mixed slurry, into a crystal transformation tank; and adding sulfuric acid and a crystal transformation agent into the crystal transformation tank, carrying out a crystal transformation reaction for 1.5-7.5 h at 60? C.-130? C., and solid-liquid separating the obtained mixed acid slurry, wherein the solid can be dried into a gypsum powder, or may be not subjected to a drying step and made into gypsum products such as gypsum boards, gypsum building blocks and gypsum members by directly adding water.