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The selective depression effect of sodium hexametaphosphate on the separation of chlorite and specularite

Zhao Fugang, Yu Xiankun, Gao Xiangpeng, Li Mingyang, Chen Xiangxiang

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 2

art. no. 166495

EN

Flotation is the most known beneficiation method for the separation of complex and refractory iron ores. As a typical iron-containing silicates, it is difficult to separate chlorite from specularite, because of the similar surface physicochemical properties. In this study, the selective depression effect of sodium hexametaphosphate (SHMP) was conducted via the cationic micro-flotation. The surface adsorption mechanism between SHMP and the two mineral surface was explored through surface adsorption amount tests, Zeta-potential measurements, Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that SHMP could selectively depress around 90% of chlorite, while its effect on the floatability of specularite was negligible (<20% depressing). The surface adsorption amount tests, Zeta-potential measurements analysis demonstrated that SHMP selectively adsorb on chlorite surface while on the surface of specularite is feeble. The further surface adsorption analysis via FT-IR and XPS proved that SHMP selective adsorption occurred on the chlorite surface mainly by chemisorption mainly through the chelation reaction between O in the phosphate groups of SHMP molecular and metal ions on surface of chlorite.

2

Effective separation of specularite and aegirite using chitosan as a novel depressant

Li Mingyang, Zhang Pengpeng, Gao Xiangpeng, Tong Xiong, Xie Xian

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 151692

EN

As a typical iron-bearing silicate gangue, aegirite often associates with specularite. Due to the iron element contained in aegirite, it has similar surface properties to specularite. Flotation is by far one of the most efficient methods of processing this kind of iron ore. But the traditional depressants unable to take action in the separation of specularite and aegirite. Chitosan was used as a novel depressant to attempt to separate specularite from aegirite through microflotation tests, adsorption tests, contact angle measurements, Zeta potential measurements, and XPS analysis. The flotation results indicate that chitosan show more strong depression effect on specularite than aegirite. Zeta potential measurements, contact angle measurements and adsorption tests demonstrate that chitosan is more inclined to adsorb on the specularite surface than aegirite, which hinders the subsequent adsorption of collector sodium oleate and increases difference in hydrophobicity between the two minerals. The XPS results of specularite validate the adsorption of chitosan on specularite, and illustrate that electrons of chitosan were partially transferred to oxygen and iron atoms in specularite during the adsorption process.

3

Comparison of the depression effect of two thiol depressants on the separation of specularite and aegirite

Li Mingyang, Zhang Chen, Gao Xiangpeng, Xie Xian, Tong Xiong

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 152164

EN

In this work, two thiol-type reagents, thioglycolic acid (TGA) and mercaptopropionic acid (MPA), were firstly exploited and compared as aegirite depressants with sodium oleate (NaOl) as the collector to separate specularite from aegirite by flotation. The adsorption performances and mechanisms of TGA and MPA on aegirite surface were investigated via flotation experiments, Zeta potential tests, adsorption measurements, contact angle dimensions, and surface characterizations. The results of flotation indicated that TGA and MPA exhibited a considerable depression impact on the flotation of aegirite but little effect on specularite. TGA depicted more excellent depression performance than MPA, which was confirmed by HLB calculation. The results demonstrated that TGA and MPA favorably adsorbed on aegirite surface instead of specularite, hindering the subsequent adsorption of NaOl on specularite and resulting in the surface being hydrophilic. XPS results revealed that TGA and MPA were significantly adsorbed on the surface of aegirite through an interaction between the carboxyl and thiol groups of the depressants and the Si and Fe on the surface of aegirite.