	US 11,753,697 B2
	Method of processing and treatment of alunite ores
Elsad Tagijev, Libeznice (CZ); Eldar Taghiyev, Libeznice (CZ); and Lale Agajeva, Libeznice (CZ)
Appl. No. 16/965,940
Filed by Elsad Tagijev, Libeznice (CZ)
PCT Filed Jan. 22, 2019, PCT No. PCT/CZ2019/000004 § 371(c)(1), (2) Date Jul. 29, 2020, PCT Pub. No. WO2019/149293, PCT Pub. Date Aug. 8, 2019.
Claims priority of application No. CZ2018-45 (CZ), filed on Jan. 30, 2018.
Prior Publication US 2021/0071281 A1, Mar. 11, 2021
Int. Cl. C22B 1/00 (2006.01); C22B 1/14 (2006.01); C01D 5/00 (2006.01); C01F 7/0613 (2022.01); C01F 7/08 (2022.01); C22B 1/02 (2006.01); C22B 3/12 (2006.01); C22B 3/22 (2006.01)

CPC C22B 1/14 (2013.01) [C01D 5/008 (2013.01); C01F 7/0613 (2013.01); C01F 7/08 (2013.01); C22B 1/02 (2013.01); C22B 3/12 (2013.01); C22B 3/22 (2013.01)]

20 Claims

1. Process for the treatment of alunite ore, comprising the following steps:

crushing of alunite ore,

grinding the alunite ore,

enrichment of the grinded alunite ore by flotation to the content of at least 50% of the alunite ore by weight,

roasting the enriched alunite ore at 520 to 620° C. for 1 to 3 hours,

preparing a sodium carbonate solution comprising 5 to 20% sodium carbonate by weight, which is later used in a first leaching step, wherein the sodium carbonate solution is added to the roasted alunite ore in a quantity of 100 to 110% of the stoichiometric amount required to bond to sulphate ions from aluminum sulfate in the roasted alunite ore, thereby forming a sodium sulphate solution wherein sodium sulphate is present at a 0 to 10% excess over the stoichiometric balance of the equation,

K₂SO₄+Al₂(SO₄)₃+2Al₂O₃+waste rock+3Na₂CO₃=K₂SO₄+3Na₂SO₄+3Al₂O₃+waste rock+3CO₂,

separating the sodium sulphate solution from an insoluble residue of the first leaching step,

converting the sodium sulphate in the preparing step with KCl to potassium sulphate and sodium chloride to form a suspension,

filtering and washing the suspension with water to form a filtrate,

evaporating the filtrate and the water, and

a second leaching step comprising treating the insoluble residue by the Bayer method without the use of an autoclave to form a product comprising aluminium oxide and quartz sand.