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1

Understanding the collection behavior of gangue minerals in fine flake graphite flotation

Xu Wenlu, Sun Kangkang, Qiu Yangshuai, Zhang Lingyan, Yang Luo, Wei Shaowei, Ding Dafa

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

101--112

EN

Flotation is one of the most common and effective methods for the beneficiation of natural graphite resources. However, the upgrading efficiency of flotation is always finite due to the undesirable collection of gangue minerals. In this work, the collecting mechanism of three typical gangue minerals, including mica, quartz, and feldspar, in fine flake graphite flotation was investigated. Results of batch flotation tests for single-minerals and artificial mixtures confirmed the enhanced collection of gangues in the presence of graphite particles. Contact angle and zeta potential results and theoretical calculations of the interaction between graphite and gangue particles based on typical DLVO theory indicated that it is impossible to collect gangue minerals by true flotation or through heterocoagulation with graphite particles. The fitting results of accumulated gangue recoveries and accumulated water recoveries using the Warren method demonstrated that most gangue minerals entered the concentrate through entrainment, with a small proportion by bubble inclusions.

2

Selective flotation of witherite from calcite using potassium chromate as a depressant

Qiu Yangshuai, Zhang Lingyan, Jiao Xuan, Guan Junfang, Li Ye, Qian Yupeng

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 2

565--574

EN

Witherite has been widely used as an industrial and environmental source of barium, with calcite being the primary associated carbonate mineral. However, few studies have been conducted to effectively concentrate witherite from barium ores. In this work, with the treatment of potassium chromate (K2CrO4) and sodium oleate (NaOL), witherite was selectively separated from calcite through selective flotation at different pH conditions. In addition, contact angle, Zeta potential, adsorption and X-ray photoelectron spectroscopy measurements were performed to characterize the separation mechanisms. The results demonstrated that NaOL had a strong collecting ability for both witherite and calcite; nevertheless, witherite could be effectively selected from calcite with the highest recovery at pH 9 in the presence of K2CrO4. From the XPS measurements, NaOL and K2CrO4 were found to be primarily attached to the surfaces of witherite and calcite through chemisorption. The presence of K2CrO4 on the surface of calcite adversely influenced the NaOL adsorption, which could make the flotation separation efficient and successful.

3

Reducing entrainment of sericite in fine flaky graphite flotation using polyaluminum chloride

Qiu Yangshuai, Zhang Lingyan, Sun Kangkang, Li Ye, Qian Yupeng

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 5

1108--1119

EN

Polyaluminum chloride (PACl) was introduced as a flocculant to reduce the entrainment of sericite gangue in fine flaky graphite flotation. The dispersion and aggregation behaviours of sericite and fine flaky graphite in the absence and presence of PACl were studied by settling experiments and verified by optical microscope images. Results of batch flotation tests for artificial mixtures indicated that the addition of PACl decreased the recovery of sericite gangue and the water recovery. Zeta potential measurements, FTIR and XPS analyses revealed that PACl selectively aggregated sericite particles in terms of charge neutralization and precipitate enmeshment.