US 2021/0269321 A1

Systems and methods to recover value-added materials from gypsum

(22) 15.05.2021

(43) 02.09.2021

(57) Disclosed herein are systems and methods from processing flue gas desulfurization (FGD) gypsum feedstock and ash feedstocks, either separately or together. FGD gypsum conversion comprises reacting FGD gypsum (calcium sulfate) feedstock or phosphogypsum, in either batch or continuous mode, with ammonium carbonate reagent to produce commercial products comprising ammonium sulfate and calcium carbonate. A process to separate the impurities and convert the calcium carbonate to a pure precipitated calcium carbonate is disclosed. These impurities include a concentrate of valuable Rare Earth Elements, and radioactive thorium and uranium. A process to convert calcium sulfite to calcium sulfate using oxygen and a catalyst is also disclosed. Ash conversion comprises a leach process followed by a sequential precipitation process to selectively precipitate products at predetermined pHs resulting in metal hydroxides which may be converted to oxides or carbonates. The processes may be controlled by use of one or more processors.

(71) Elixsys, inc., Bainbridge Island, WA (US)

(73) Elixsys, Inc., Bainbridge Island, WA (US)

x

Related articles:

Issue 2016-9 WO 2016/115398 A1

Controlled process for precipitating calcium carbonate and vaterite precipitated calcium carbonate compositions formed by said process

(22) 14.01.2016 (43) 21.07.2016 (57) A process for converting gypsum into precipitated calcium carbonate including reacting a mixture comprising gypsum and a seed, a mineral acid, or both with at...

more
Issue 2017-1-2 US2016339383 (A1)

Desulfurization apparatus and exhaust gas processing system using the same

(43) 24.11.2016 (57) A desulfurization apparatus employing the limestone-gypsum method has: a desulfurization unit where an absorbing liquid containing a calcium compound contacts with an exhaust gas...

more
Issue 2017-3 US 2017/0022070 A1

System and methods for ­removing ­impurities from phosphogypsum and manufacturing gypsum binders and products

(22) 02.04.2015 (43) 26.01.2017 (57) Methods and systems that remove impurities from phosphogypsum (PG), including from radium and heavy metal salts, and produce gypsum binders and products. In one...

more
Issue 2018-11 EP3371100 (A1)

Method for reducing elemental sulfur in gypsum products

(22) 03.11.2016 (43) 12.09.2018 (57) Disclosed are various methods for reducing levels of elemental sulfur within gypsum products such as wall board. Gypsum sometimes includes increased levels of...

more
Issue 2021-7 GB 2591262 A

Building product

(22) 23.01.2020 (43) 28.07.2021 (57) (Abstract title): Building product formed from a calcium carbonate binder and a lignocellulosic bio-aggregate: A bio-aggregate based building product formed from a...

more