GB 2557605 A

Method of producing high purity gypsum

(22) 09.12.2016

(43) 27.06.2018

(57) Releasing impurities from a calcium-based mineral to produce pure double salt crystals for producing high quality gypsum and chalk – A method for releasing impurities from a calcium-based mineral with an aqueous solution of one or more ionic salts at a temperature of approximately 85°C or above, preferably 100°C, e.g. at 1-2 atmospheres, wherein the calcium based mineral is any mineral having a significant calcium component in the form of calcium carbonate (CaCO3), or calcium sulphate (CaSO4), or calcium oxide (CaO) and the one or more ionic salts comprise any of ammonium sulphate; ammonium chloride; and sodium sulphate, at least one of the calcium-based mineral and the one or more ionic salts comprises sulphate and at least one of the calcium-based mineral and the one or more ionic salts comprises ammonium. The concentration of the solution is approximately 25% or higher mass fraction such that double salt crystals, e.g. koktaite ((NH4)2SO4•CaSO4•H20) are formed and impurities are released. The double salt crystals may be separated and converted to chalk; and may be reacted in an aqueous solution to precipitate gypsum which may be converted to chalk. The method is designed to produce high quality gypsum, e.g. primarily calcium sulphate dehydrate.

(71) Carbon Cycle Limited, 248 Sutton Common Road, Sutton, Surrey, SM3 9PW, United Kingdom

x

Related articles:

Issue 4/2023 WO 2023/054239 A1

Method for fixing carbon dioxide, method for producing calcium carbonate, and method for utilizing waste gypsum board

(22) 26.09.2022 (43) 06.04.2023 (57) The present invention provides a method whereby carbon dioxide can be efficiently fixed and calcium carbonate, which is a valuable, can be efficiently produced...

more
Issue 1-2/2019 US 2018/0305257 A1

Gypsum set accelerator and method of preparing same

(22) 12.03.2018 (43) 25.10.2018 (57) A modified gypsum set accelerator and a method of preparing the same is provided, which includes dry loose finely ground particles of a mixture of ground dry...

more
Issue 5/2021 US 2021/0130234 A1

Method and system for producing low-alkalinity sulphoaluminate cement with new mineral system using steel slag

(22) 28.02.2020 (43) 06.05.2021 (57) A method and system for producing low-alkalinity sulphoaluminate cement with a new mineral system using steel slag. The method includes the following steps: evenly...

more
Issue 5/2017 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...

more
Issue 7-8/2016 US 2016/0159692 A1

Method for producing nano-cement, and nano-cement

(22) 25.11.2015 (43) 09.06.2016 (57) The invention is related to nanocement production methods by modifying Portland cement, as well as to nanocement compositions. The nanocement production method...

more