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1

Study on the mechanism of the difference in flotation performance between fine-grained crystalline SiO2 and amorphous SiO2

Ma Saisai, Li Jie, Wang Yonglun, Wei Bangqi

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 174567

EN

Numerous minerals found in nature contain silica, including quartz, cristobalite, opal, etc. They have the same chemical composition but different crystal structures, and this phenomenon is called “polymorphism” in mineralogy. For these polymorphic and multi-like minerals, in the flotation process, will it directly or indirectly affect the flotation effect. Based on this, this study mainly explores the difference between crystalline SiO2 and amorphous SiO2 in flotation. In this study, two crystal forms of SiO2 were subjected to flotation and adsorption capacity tests. FTIR, other test techniques, the chemical calculation of the flotation solution, and the theoretical calculation of the DLVO can all be used to provide an explanation. Finally, in the flotation experiment, the feedbacks of the two minerals to the change of the pH value of the pulp and the change of the concentration of the reagent are different. Through the comprehensive analysis of the adsorption capacity test and semi-quantitative calculation of the infrared spectrum, the adsorption capacity of crystalline SiO2 to drugs is about 23% higher than amorphous SiO2. Furthermore, during the flotation process, the amorphous SiO2 particles will agglomerate together and entrain into the foam through, resulting in concentrate pollution. So amorphous SiO2 will undoubtedly increase the difficulty of flotation.

2

Effective flotation separation of scheelite and calcite by applying methylene phosphonic acid sodium as a novel and green depressant

Zhou Hepeng, Wu Handan, Guo Jiangfeng, Tang Xuekun, Huang Wen, Luo Xianping

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 3

art. no. 168517

EN

It is known that the flotation separation of scheelite and calcite is quite difficult due to their similar surface properites. To slove the problem, ethylenediaminetetra (methylene phosphonic acid) sodium (EDTMPS), an environmentally friendly reagent, was employed as an efficient depressant for flotation separation of calcite for the first time. In flotation experiments, it demonstrates that EDTMPS could strongly inhibit the flotation of calcite but barely affect the flotaiton behavior of scheelite, showing excellent dpress ability and selectivity. Based on a series of measurements including contact angle analysis, zeta potential, and XPS analysis, it was found that large amout of EDTMPS could be absorbed on the surface of calcite through strong chemical chelation reaction and thus inhibiting the further adsorption of NaOL. On the contrary, little EDTMPS was absorbed on that of scheelite owing to the negatively charged tungstate ions on the surface in relative terms. All in all, these results exhibit EDTMPS has excellent selective inhibition ability on calcite, which can be potentially applied in actual scheelite and calcite flotation separation process.

3

A nanoparticle cationic polystyrene-co-poly(n-butylacrylate) collector to eliminate the negative effect of lizardite slimes in pyrite flotation

Ai Guanghua, Liu Cheng, Zhu Guangli, Yang Siyuan

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 3

art. no. 170899

EN

Lizardite slime coating is one of significant factors in the deterioration of the floatability of sulphide minerals. In this study, a nanoparticle cationic polystyrene-co-poly(n-butylacrylate)(PS-PBNH) collector was introduced to eliminate the negative impact of lizardite slimes in pyrite flotation. Microflotation results demonstrated that lizardite slims did not affect the recovery of pyrite in the presence of PS-PBNH. Good flotation separation of pyrite from lizardite was achieved when the nanoparticle PS-PBNH collector was used. The results from adsorption study indicated that PS-PBNH exhibited a significant adsorption on the pyrite surface in the presence of lizardite slimes. Sedimentation tests showed that hetero-aggregation occurred between lizardite slimes and pyrite, whereas the introduction of PS-PBNH collector resulted in a heterogeneous dispersion between them. Zeta potential measurements suggested that PS-PBNH collector interacted with pyrite surface, and the PS-PBNH adsorption changed the surface charge of pyrite from negative to be positive. As a result, the interaction of pyrite with lizardite shifted from electrostatic attraction to electrostatic repulsion, as supported by the DLVO calculations. These results indicated PS-PBNH can be used as a potential collector for pyrite flotation in pyrite/lizardite slimes system without the need for a depressant.

4

Investigating the selectivity of calcium hypochlorite for flotation separation of chalcopyrite and pyrite pre-adsorbed collector

Yang Wenhui, Qiu Xianhui, Yan Huashan, Wu Hao, Yang Liu, Lai Ruisen, Qiu Tingsheng

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 150703

EN

Bulk flotation is usually used in the flotation of Cu-Fe sulfide ore, and the subsequent concentrate is difficult to be separated because the minerals have adsorbed the collector. In this paper, flotation tests showed that calcium hypochlorite (Ca(ClO)2) had a stronger depression effect on pyrite pre-adsorbed sodium butyl xanthate (SBX), while having a negligible depressive effect on chalcopyrite. A copper concentrate with Cu grade of 33.32% and Cu recovery of 94.47% could be obtained from flotation tests of mixed minerals. The depression performance and mechanism of Ca(ClO)2 were studied by contact angle measurements, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses, the results suggested that Ca(ClO)2 can decomposes SBX on the pyrite surface and oxidizes the mineral surface to form hydrophilic substances, which enhances the hydrophilicity of the pyrite surface. In contrast, Ca(ClO)2 has little effect on chalcopyrite pre-adsorbed SBX, the possible depression model is discussed.

5

Research on the mechanism of a mixed collector onto magnesite surface to improve the flotation separation of magnesite from hornblende

Wang Enlei, Li Xiaoan, Dai Shujuan, Li Zhao, Zhao Tonglin, Song Baoxu, Han Baisui

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 4

125--138

EN

Low-grade magnesite is not effectively used mainly due to high silicon content, especially the separation of magnesite and hornblende. In this research, a novel mixture of sodium oleate and dodecyl phosphate collector was used to increase the flotation difference between magnesite and hornblende. Artificially mixed mineral concentrates grade 47.10% (MgO content) concentrate recovery of 84.45% was obtained by micro flotation test, the results showed that the mixed collector of sodium oleate and dodecyl phosphate played a better selective promotion role in the flotation of magnesite. The interaction mechanism of this mixed collector with hornblende and magnesite surfaces was investigated using Fourier transform infrared spectroscopy (FTIR), zeta potential, and X-ray photoelectron spectroscopy (XPS), which showed that the mixed collector in terms of magnesium selection was mainly adsorbed on these magnesium sites of magnesite, and the surface of magnesite thus became hydrophobic, allowing magnesite to float and separate from hornblende.

6

Influence of particle size on flotation separation of ilmenite, olivine, and pyroxene

Yang Yaohui, Xu Longhua, Liu Shujun, Deng Jian

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 5

106--117

EN

The rock type in Panxi area is changing from gabbro type to olivine pyroxene type, which makes it difficult for enterprises to obtain better beneficiation indexes at present. In order to solve this problem, we use a variety of modern test techniques, such as zeta potential measurements, Fourier-transform infrared (FTIR) spectroscopy, adsorption amount measurements, and mineral-reagent interaction energy simulation to analyze the influence of particle size on mineral flotation behavior and the interaction of fine-grained minerals in this paper. The experiments results indicate that the presence of fine-grained (-19 um) mineral particles is deleterious to the flotation of ilmenite, the ilmenite recovery decreases as the microfine grade content of pyroxene and olivine increases, distribution of narrow size minerals is beneficial to the minerals flotation performance, and the order of sodium oleate (NaOL) adsorption strength on different ilmenite crystal planes is (1011) > (0001). The research results of this paper deepen the understanding of the olivine type ilmenite resources in Panxi area, enrich the theoretical system of flotation separation of refractory ilmenite, and provide theoretical support for the key technical problems of flotation separation of ilmenite in Panxi area.

7

Effect of compound phosphate collector on flotation separation of jamesonite from marmatite and insights into adsorption mechanism

Huang Weiqin, Gu Guohua, Chen Xiong, Wang Yanhong

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

294--304

EN

Separating jamesonite and marmatite is difficult due to their similar response to traditional collectors. To improve the selectivity of the collector and simplify the reagent system, compound phosphate (MP) as a collector for the separation of jamesonite from marmatite was studied in this study. The flotation tests revealed that, compared with the most used butyl xanthate (BX), MP had the advantages of lower dosage and stronger selectivity under weak acid pulp. Under the optimum flotation conditions, a concentrate with the grade of 31.54% Pb, 6.93% Zn and the recovery of 89.87% Pb, 12.31% Zn could be obtained from mixed binary minerals flotation (mass ratio of 1:1). Adsorption, zeta potential, FT-IR and XPS analysis demonstrated that MP performed strong chemisorption on jamesonite surface while underwent weak physisorption on marmatite, this difference was responsible for the excellent selectivity of MP toward jamesonite flotation and weak collecting capacity to marmatite.

8

Study of N, N-bis (2-hydroxyethyl) -N-methyl dodecyl ammonium chloride as the novel collector in selective flotation separation of quartz and hematite

Liu Wenbao, Liu Wengang, Zhao Qiang, Wang Xinyang, Duan Hao, Peng Xiangyu, Wang Benying

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

286--299

EN

A quaternary ammonium salt, N, N-bis (2-hydroxyethyl)-N-methyl dodecyl ammonium chloride (BHMDC), with high surface activity, was screened and firstly introduced in the reverse flotation of hematite ores based on Density Functional Theory (DFT) calculation and surface tension measurement. The interaction mechanism of BHMDC on the surfaces of quartz and hematite was studied by zeta potential measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transforms infrared spectroscopy (FTIR), respectively. The results of DFT calculation and surface tension measurement indicated that BHMDC had higher selectivity and hydrophobicity than dodecylamine (DDA). The analyses of zeta potential measurement, FTIR, and XPS demonstrated that the adsorption of BHMDC on hematite and quartz surfaces were mainly dependent on hydrogen bonding and electrostatic interaction. Due to the more active sites (O atoms), the weaker charge and larger size of polar groups, BHMDC had better simulation results in performance than DDA, especially in selectivity. The flotation tests showed that BHMDC exhibited better flotation performance, which was consistent with the results of DFT calculation. And the efficient separation of hematite and quartz within the wide pH value range (4.0-10.0) was determined, which was also confirmed by zeta potential measurement. It also indicated that BHMDC was an excellent collector in the reverse flotation of hematite ores with great industrial potential, which could obtain the concentrate with the Fe grade of 65.37% and recovery of 88.92%

9

Flotation separation of rutile from almandine using octadecyl amine polyoxyethylene ether as collector

Li Hongqiang, Zheng Huifang, Chen Qian, Kasomo Richard M., Leng Jiahao, Weng Xiaoqing, Song Shaoxian, Xiao Linbo, Tian Chengtao

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 4

653--664

EN

In this study, the flotation separation of rutile from almandine using cationic surfactant Octadecyl amine polyoxyethylene ether (AC1815) as a new collector was investigated. The adsorption mechanism of AC1815 on rutile was illustrated through zeta potential measurement, infrared spectrum and XPS analyses. The flotation experiments demonstrated that AC1815 exhibited an excellent collecting ability and selectivity for rutile. The results of zeta potential measurements and XPS analysis indicated that more AC1815 was adsorbed on rutile surface instead of almandine. The adsorption mechanism of AC1815on rutile was mainly attributed to the electrostatic interaction between the positively charged molecules of AC1815 and the negatively charged rutile surface, and the hydrogen bonding between the protonated ≡NH+, ≡N group of AC1815 and Ti-OH on rutile surface.

10

Effect of grinding media on the flotation of copper-activated marmatite

Long Tao, Chen Yao, Shi Juanjuan, Chen Wei, Zhu Yangge, Zhang Chonghui, Bu Xianzhong

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

229--237

EN

How to avoid the shortage of floatability and non-purpose flotation in marmatite flotation is a big problem. This paper innovatively studies how to reduce these two negative phenomena from the perspective of grinding media. The effects of steel and stainless-steel balls on the flotation performance of copper-activated marmatite were investigated mainly through flotation tests, redox potential measurements, ion concentration tests, and XPS and FT-IR spectrum studies. The flotation results showed that the floatability of copper-activated marmatite remarkably decreased by using the steel ball in the grinding process, but it had a mere influence when stainless-steel medium was used. Redox potential measurements showed that the grinding environment of stainless-steel medium could exhibit a higher oxidizing potential than the steel grinding environment. Results from FTIR, XPS, and ion concentration measurements demonstrated that more ferric ions existed on the copper activated marmatite surface in the steel grinding environment than that in the stainless-steel environment. Ferric ions could further hinder the activation effect of copper ions on marmatite and result in decreased marmatite flotation. This research could potentially explain the mechanism of ferric ions in the grinding process, and it can be utilized to improve the flotation performance of marmatite ore through selecting suitable grinding media in ball mill operations.

11

Utilization of N-carboxymethyl chitosan as a selective depressant for talc in flotation of chalcopyrite

Liu Cheng, Feng Qiming, Shi Qing, Zhang Wencai, Song Shaoxian

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

108--115

EN

Flotation separation of chalcopyrite from talc is difficult because of the natural hydrophobicity of two minerals. In this work, the flotation separation of chalcopyrite from talc using N-carboxymethyl chitosan as a depressant for talc was studied. The micro-flotation results indicated that the flotation separation of chalcopyrite from talc cannot be realized effectively at pH 9 with low concentration of N-carboxymethyl chitosan, in the presence of calcium ions, talc was more efficiently depressed by N-carboxymethyl chitosan, while the chalcopyrite recovery was not influenced. Contact angle, zeta potential and adsorption results showed that Ca2+ and CaOH+ absorbed on the talc surface and increased the absorption amount of N-carboxymethyl chitosan on the mineral surface, and increased hydrophilicity of talc surface, resulting the selective depression for talc in chalcopyrite flotation.

12

Effect of pulp temperature on separation of magnesite from dolomite in sodium oleate flotation system

Yin Wanzhong, Sun Haoran, Tang Yuan, Hong Jongsu, Yang Bin, Fu Yafeng, Han Huili

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 4

1049--1058

EN

The influence of pulp temperature on the floatability of magnesite and dolomite were studied by flotation test. Inductive Coupled Plasma Emission Spectrometer (ICP) was used to measure the dissolved metal ion content in the pulp by minerals in solution. X-ray photoelectron spectroscopy (XPS) was used to measure the presence and relative content of metal ions on mineral surfaces and the amount of sodium oleate adsorbed on mineral surfaces was measured by UV-Visible Spectrophotometer (UV-Vis). The results show that magnesite and dolomite have a great difference in flotation performance when the pulp temperature is 15 ℃ and the effective separation of magnesite from dolomite can be achieved. The main reason is that after the pulp is stirred at a pulp temperature of 15 ℃ and the pH of the pulp is adjusted with HCl and NaOH, the amount of metal ions remaining on the surface of the magnesite is much larger than that on the surface of the dolomite. Therefore, the active targets (metal ion) adsorbing oleate ions on the surface of the magnesite are more than that on the dolomite. When magnesite and dolomite coexist, oleic acid ion mainly acts on the surface of magnesite at the optimum temperature, which makes magnesite float up and the separation of magnesite from dolomite could be achieved.

13

Flotation kinetics and thermodynamic behavior of chalcopyrite and pyrite in high alkaline systems

Yan H., Yuan Q., Zhou L., Qiu T., Ai G.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

901--910

EN

The monomineral flotation test and microcalorimetry were used to study the flotation kinetics and thermodynamic behavior of chalcopyrite and pyrite in high alkaline systems of lime and NaOH. The results showed that in these systems there were less hydrophilic substances on the chalcopyrite surface, so that the apparent activation energy of sodium butyl xanthate (SBX) adsorption on chalcopyrite surface was low. This promoted the adsorption of SBX and increased the flotation rate and recovery of chalcopyrite. In contrast, the hydrophilic Fe(OH)3 and SO42- formed by oxidation on the pyrite surface increased the adsorption activation energy of SBX. Thus, the flotation rate and recovery of pyrite were lower. Moreover, in the lime high alkaline system, the hydrophilic calcium film generated on the pyrite surface further hindered the adsorption of SBX, thereby further inhibiting pyrite in this environment. In other words, the lime high alkaline environment increased the apparent activation energy difference of SBX adsorption between chalcopyrite and pyrite compared to the NaOH system, facilitating the flotation separation of chalcopyrite and pyrite. The results can help with the theoretical research of flotation separation of other minerals, and provide guidance for developing low alkaline and lime-free pyrite depressants.