WO 2017/045519 A1

Method for producing wet-process phosphoric acid and ­byproducing alpha-hemihydrate gypsum and high-purity and high-whiteness alpha-hemihydrate gypsum

(22) 26.08.2016

(43) 23.03.2017

(57) Provided is a method for producing wet-process phosphoric acid and by-producing alpha-hemihydrate gypsum and high-purity and high-whiteness alpha-hemihydrate gypsum. The method comprises: adding phosphoric acid and a phosphate rock powder into an extraction tank and conducting an extraction reaction on same, then adding sulfuric acid to continue the reaction so as to make 30 %-50 % of calcium ions form dihydrate gypsum, the dihydrate gypsum part being sent to a crystal transformation tank, a crystal transformation agent being added, and crystal transformation conditions being controlled so as to obtain 30 %-50 % of an ordinary alpha-hemihydrate gypsum; and make the other 50 %-70 % of calcium ions be present in the form of calcium dihydrogen phosphate in a phosphoric acid extractive solution, separating same and then introducing the phosphoric acid extractive solution into a decalcification reaction tank, adding a sulfuric acid solution diluted by a washing solution, and then firstly performing decalcification, and then controlling the crystal transformation conditions and subjecting a solid to a crystal transformation reaction, so as to generate a highpurity and high-whiteness alpha-hemihydrate gypsum. The method not only reduces the content of phosphorus in the by-product alpha-hemihydrate gypsum, but also realizes the industrial production of phosphoric acid and by-products ordinary alphahemihydrate gypsum and high-purity and high-whiteness alpha-hemihydrate gypsum by a wet-process.

(71) Kingenta Norsterra Chemical Co., Ltd (CN)

x

Related articles:

Issue 2018-7-8 KR101839251 (B1)

Alkali gypsum and method for producing alkaline gypsum using de-sulfurized slag admixture slagcement and concrete composition comprising the alkali gypsum

(22) 20.12.2016 (43) 26.04.2018 (57) The present invention relates to a method for producing an alkali gypsum for admixture of ordinary cement or slag cement using a desulfurized slag fine powder...

more
Issue 2020-9 US 2020/0123055 A1

Recycling method of dihydrate gypsum from waste gypsum boards

(22) 22.10.2019 (43) 23.04.2020 (57) Gypsum derived from waste gypsum boards is calcined and converted into gypsum granules including hemihydrate and/ or anhydrous type III gypsum. The calcined gypsum...

more
Issue 2016-6 HK 1210135 A1

Gypsum composition, gypsum slurry, gypsum hardened body, gypsum-based construction material, gypsum board, and ­method for producing gypsum-based construction material

(22) 02.11.2015 (45) 15.04.2016 (57) Summary of corresponding patent EP2896605 A1: [Problems] An object is to provide a gypsum composition, a gypsum slurry, a gypsum hardened body, a gypsum-based...

more
Issue 2015-7-8 WO?2015/085139?A1

Gypsum composite modifiers

(22) 05.12.2014 (43) 11.06.2015 (57) Anhydrite calcium sulfate whiskers are prepared by combining alpha calcium sulfate hemihydrate and water to form a slurry, autoclaving the slurry to form alpha...

more
Issue 2019-1-2 US 2018/0273429 A1

Gypsum-cement dry mix and prefabricated construction parts produced therefrom

(22) 29.09.2016 (45) 27.09.2018 (57) The invention relates to a gypsum-cement dry mix, the use thereof and a method for producing prefabricated construction parts using the gypsum-cement dry mix. For...

more