US 12,031,044 B2
Process for preparing whitened fly ash
Erik Severin, Kowloon (HK); Erwin N. Fernandez, Kowloon (HK); and John Vincent Adap Misa, Kowloon (HK)
Assigned to Vecor IP Holdings Limited, Hong Kong (HK)
Appl. No. 18/020,772
Filed by VECOR IP HOLDINGS LIMITED, Kowloon (HK)
PCT Filed Aug. 13, 2021, PCT No. PCT/EP2021/072598
§ 371(c)(1), (2) Date Feb. 10, 2023,
PCT Pub. No. WO2022/034214, PCT Pub. Date Feb. 17, 2022.
Claims priority of application No. 20191116 (EP), filed on Aug. 14, 2020.
Prior Publication US 2023/0287220 A1, Sep. 14, 2023
Int. Cl. C09C 3/00 (2006.01); B03B 9/04 (2006.01); B03C 1/00 (2006.01); B03C 1/28 (2006.01); B03C 1/30 (2006.01); B09B 3/35 (2022.01); B09B 3/40 (2022.01); B09B 3/70 (2022.01); C08K 11/00 (2006.01); C09C 1/00 (2006.01); C09C 3/04 (2006.01); C09D 7/40 (2018.01); C09D 7/61 (2018.01); B09B 101/30 (2022.01)
CPC C09C 3/006 (2013.01) [B03B 9/04 (2013.01); B03C 1/002 (2013.01); B03C 1/28 (2013.01); B03C 1/30 (2013.01); B09B 3/35 (2022.01); B09B 3/40 (2022.01); B09B 3/70 (2022.01); C08K 11/005 (2013.01); C09C 1/0009 (2013.01); C09C 3/003 (2013.01); C09C 3/041 (2013.01); C09C 3/043 (2013.01); C09D 7/61 (2018.01); C09D 7/69 (2018.01); B03C 2201/18 (2013.01); B03C 2201/20 (2013.01); B09B 2101/30 (2022.01); C01P 2004/52 (2013.01); C01P 2004/61 (2013.01); C01P 2006/80 (2013.01); C08K 2201/005 (2013.01)] 12 Claims
 
1. A process for preparing whitened fly ash, wherein the process comprises the steps of:
(a) subjecting fly ash to a size classification step to obtain size classified fly ash having a particle size such that at least 90 wt % has a particle size of from 44 μm to 250 μm;
(b) contacting the size classified fly ash from step (a) with water so as to form a slurry, wherein the slurry has a solid content of less than 40 wt %;
(c) subjecting the slurry obtained in step (b) to an exhaustive magnetic separation step to form magnetically treated fly ash, wherein the exhaustive magnetic separation step comprises a first magnetic extraction step and a second magnetic extraction step, wherein the second magnetic extraction step is carried out at a higher magnetic field strength than the first magnetic extraction step, and each magnetic extraction step has a duration of at least 1 minute; and
(d) subjecting the magnetically treated fly ash obtained in step (c) to a wet milling step to form whitened fly ash, wherein the wet milling step is carried out in the presence of an acid.