Preparation of high-purity SiO2 by S-HGMS coupled with mixed-acid leaching : A case study on hematite tailings from Ansteel, China

Copyright © 2023 Elsevier Ltd. All rights reserved..

Hematite tailings (HTs) are rich in silica and are used as replacements for fine aggregates in the preparation of construction materials. However, there is scope for a more effective utilization of the valuable elements present in HTs. In this paper, a process for preparing high-purity SiO2 using HTs procured from Ansteel (China) is proposed. HTs were treated using the superconducting high-gradient magnetic separation (S-HGMS) technology, where the silica as part of the nonmagnetic fraction was obtained in the form of a high-silica concentrate, which was then subjected to mixed-acid leaching to dissolve impurities to achieve refined purification. The optimum process conditions for S-HGMS were determined, and the response surface methodology was applied to optimize the process parameters of the mixed-acid leaching process. The process indicators of the mixed-acid leaching step included the leaching time, leaching temperature, and molar ratio of the mixed acids. The optimum process conditions for S-HGMS were as follows: the magnetic strength-to-velocity ratio in the weak magnetic separation stage was set to 0.034 T·s/m whereas it was maintained at 0.076 T·s/m in the strong magnetic separation stage; the pulp concentration was 40 g/L, the pulp velocity was 500 mL/min, and the dispersant concentration was 1 mg/g. Under these conditions, the high-silica pulp was processed. The corresponding SiO2 grade increased from 71.788 % to 95.260 %, and its recovery and yield reached 56.330 % and 42.450 %, respectively. The SiO2 content in the sample increased from 95.260 % to 99.961 %. Further, the mechanisms of the S-HGMS and mixed-acid leaching were revealed. The proposed process is environmentally friendly and operationally inexpensive. It can reduce the amount of HTs by 42.450 %, and the obtained high-purity silica product has high economic value and good industrialization prospects.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:174

Enthalten in:

Waste management (New York, N.Y.) - 174(2024) vom: 15. Jan., Seite 240-250

Sprache:

Englisch

Beteiligte Personen:

Li, Cong [VerfasserIn]
Yang, Xiaofeng [VerfasserIn]
Li, Yongkui [VerfasserIn]
Chen, Yu [VerfasserIn]
Pan, Xiaodong [VerfasserIn]
Xie, Yongping [VerfasserIn]
Liu, Xingyu [VerfasserIn]
Li, Suqin [VerfasserIn]

Links:

Volltext

Themen:

1K09F3G675
7631-86-9
Ferric Compounds
Ferric oxide
Hematite tailings
High-purity SiO(2)
Industrial solid waste
Journal Article
Mixed-acid leaching
S-HGMS
Silicon Dioxide

Anmerkungen:

Date Completed 16.01.2024

Date Revised 16.01.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.wasman.2023.11.026

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM36561257X