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1

Exploration on flotation behavior of galena in seawater and related mechanism

Song Ningbo, Sun Chuanyao, Yin Wanzhong, Yao Jin, Yang Bin

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 151524

EN

The utilization of seawater in mineral flotation is the future development trend because of the shortage of fresh water resources. However, at present, the flotation behavior and mechanism of galena in seawater are not clear. Therefore, this paper comprehensively carried out the effect mechanism of seawater on the flotation of galena. Micro-flotation results illustrated that the recovery of galena was higher in deionized water than that in 5×10-2 mol/L MgCl2 solution, 1×10-2 mol/L CaCl2 solution and seawater. Contact angle determination and Zeta potential distribution measurements showed that hydrophilic substances adsorbed on the surface of galena under alkaline conditions. X-ray photoelectron spectroscopy (XPS) analysis further indicated that these substances were hydroxides precipitates, carbonate precipitates and hydroxyl complexes formed by divalent magnesium and calcium ions, which prevented the adsorption of collector on mineral surface. As a result, the galena recovery declined in 5×10-2 mol/L MgCl2 solution, 1×10-2 mol/L CaCl2 solution and seawater.

2

Effects of copper ions on malachite sulfidization flotation

Yin Wanzhong, Sheng Qiuyue, Ma Yingqiang, Sun Haoran, Yang Bin, Tang Yuan

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

300--312

EN

In this study, the effects of copper ions (Cu2+) on the sulfidization (Na2S) flotation of malachite was investigated using micro-flotation experiments, zeta-potential measurements, X-ray photoelectron spectroscopy (XPS) analysis, adsorption experiments, and Materials Studio simulation. The results indicated that the flotation recovery of malachite decreased after the pretreatment of the mineral particles with Cu2+ ions prior to the addition of Na2S. The results for zeta-potential measurements and XPS analysis revealed that less sulfide ion species in the pulp solution transferred onto the mineral surface, the sulfidization of malachite surface weakened. The adsorption amount of collector on the mineral surface decreased, and this finding was confirmed by the results of the zeta-potential and adsorption experiments. Materials Studio simulation revealed that the adsorption energy of HS- ions and C4H9OCSS- ions on malachite surface increased after the adding of Cu2+ ion. The competitive adsorption made Cu2+ ions depress sulfidization flotation of malachite, the dissolution of mineral surface affected the adsorption of reagents on it, and decreased the floatability of malachite.

3

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.

4

Three-way Decisions with Rough Membership Functions in Covering Approximation Space

Yang Bin, Hu Bao Qing, Quiao Junsheng

Fundamenta Informaticae

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2019

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Vol. 165, nr 2

157--191

EN

Rough membership functions in covering approximation space not only give numerical characterizations of covering-based rough set approximations, but also establish the relationship between covering-based rough sets and fuzzy covering-based rough sets. In this paper, we give a new method to discuss three-way decisions with rough membership functions in covering approximation space. Firstly, we introduce three new types of rough membership functions and study their properties. And then, relationship between a covering and its derived fuzzy β-covering is investigated by using rough membership functions. In addition, we study the relationship among the four types of rough membership functions. Finally, a novel type of graded covering-based rough set model is proposed on the basis of rough membership function. And, as an application, its corresponding three-way decisions in incomplete decision systems are investigated.