Abrégé

5, the polymerization rate of the polyphosphoric acid calcium magnesium fertilizer is ≥50%. The present invention also provides a preparation method for the fertilizer. The phosphorus in the product prepared by the invention has sustained-release properties. The fertilizer is well suited for crops requiring large amounts of calcium and magnesium.

Classes IPC  ?

• C05B 13/06 - Engrais de méta- ou polyphosphates alcalins ou alcalino-terreux
• C05D 3/02 - Engrais calciques à partir de pierre à chaux, carbonate de calcium, hydrate de calcium, de chaux éteinte, oxyde de calcium, composés calciques résiduaires
• C05D 5/00 - Engrais magnésiens

Abrégé

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.

Classes IPC  ?

• C01B 25/229 - Procédé du type hémihydrate-dihydrate
• C01F 11/46 - Sulfates
• C01B 25/22 - Préparation par réaction de produits contenant un phosphate avec un acide, p. ex. procédé par voie humide

Abrégé

Provided is a method for producing phosphoric acid and by-producing alpha-hemihydrate gypsum by a wet-process. The method comprises: first 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 residual 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 thereto. The method can eliminate discharges of a phosphogypsum and an acid insoluble substance, reduce the content of phosphorus in gypsum, improve the utilization rate of phosphorus, make full use of the dilution heat of concentrated sulfuric acid, and realize energy saving and emission reduction.

Classes IPC  ?

• C01B 25/222 - Préparation par réaction de produits contenant un phosphate avec un acide, p. ex. procédé par voie humide avec l'acide sulfurique, avec un mélange d'acides consistant principalement en acide sulfurique ou un mélange de composés formant de l'acide sulfurique in situ, p. ex. avec un mélange d'anhydride sulfureux, d'eau et d'oxygène
• C01B 25/18 - Acide phosphorique
• C01F 11/46 - Sulfates

Abrégé

Provided is a method for producing phosphoric acid and by-producing alpha-hemihydrate gypsum by a wet-process. The method comprises: first 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 residual 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 thereto. The method can eliminate discharges of a phosphogypsum and an acid insoluble substance, reduce the content of phosphorus in gypsum, improve the utilization rate of phosphorus, make full use of the dilution heat of concentrated sulfuric acid, and realize energy saving and emission reduction.

Classes IPC  ?

• C01B 21/38 - Acide nitrique
• C01F 11/46 - Sulfates

Produits et services

Manure for agriculture; fertilizers; humus; calcium superphosphate (fertilizers); compound fertilizer; phosphate fertilizer (fertilizer).

Produits et services

Manure for agriculture; fertilizers; compost; humus; phosphate fertilizer (fertilizer); calcium superphosphate (fertilizers).

Produits et services

Manures for agriculture; fertilizers; humus; phosphates [fertilisers]; superphosphates [fertilisers]; compost.

Produits et services

Fertilizers; manure for agriculture; phosphates [fertilisers]; plant growth regulating preparations; compost; fertilizing preparations.