POWDER TECHNOLOGY
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2018
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IF 3.23
Zhilin Xi,Liwei Jin,J.Y. Richard Liew,Ding Li
A foam sol clay (FSC) mixture, mainly composed of fly ash (FA), surfactant ( n -amylamine) and polyethylene oxide (PEO), was proposed for coal dust control. The FA surface, modified by a FSC solution, stability and foamability were investigated. It was found that the FA surface in alkaline solution was deprotonated to form a negative charge, which could be adsorbed by the polar head group of n -amylamine via electrostatic interactions . As a result, with increasing surfactant, the particles gradually converted from hydrophilic to hydrophobic and attached at gas-liquid interfaces so that the contact angle, zeta potential , froth stability and foamability increased. At a surfactant concentration (c a ) of 35 g/L, a monolayer three-dimensional network was formed and the maximum foamability and half-life were obtained. Upon further increasing c a , a bilayer and particle clusters were formed by surfactant chain-chain interaction, resulting in particles becoming hydrophilic again, and the FSC solution having stronger mechanical resistance against flowing, so that the viscosity rapidly increased and the diffusion of free surfactant molecules was hindered at the froth surfaces. Thus, the contact angle, froth stability and foamability decreased. PEO could bond sodium dodecyl sulfate and water to form a dual adsorption layer and hydrogen, respectively, which enhanced the wettability of the FSC on coal dust surfaces. PEO could adsorb and curl FA particles to form a thin layer of armor after froth air-drying. It was concluded that the froth generated by the FSC solution, including 200 g/L FA, 35 g/L c a and 1 g/L PEO, could control coal dust with a long-term effect.
研究领域:
环境工程
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矿物加工
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胶体与界面化学
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粉尘防治
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资源利用
✓ 已验证
DOI
高影响因子
APPLIED CLAY SCIENCE
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2017
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IF 3.101
Ning Mao,Chun Hui Zhou,John Keeling,Saverio Fiore,Hao Zhang,Liang Chen,Gui Chen Jin,Ting Ting Zhu,Dong Shen Tong,Wei Hua Yu
Dolomite is a widespread carbonate mineral that has been investigated extensively over the past two centuries. Despite the high level of investigation, aspects of the environmental conditions of crystallization, diagenesis and dissolution remain elusive and the transformation of dolomite into other value-added products is still challenging. This work shows a novel, cleaner method to dissolve dolomite by taking advantage of the acidity from the hydrolysis of Lewis acid AlCl 3 and as such the mineral can be efficiently converted into Ca-Mg-Al layered double hydroxide (LDH). The dolomite and the resulting Ca-Mg-Al LDH samples were characterized by powder X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composition of the products was measured by energy dispersive spectrometer-mapping (EDS-mapping), X-ray fluorescence (XRF) and atomic absorption spectroscopy (AAS). Particle sizes of the products were measured by a dynamic light scattering method. It is documented, for the first time, that dissolution of dolomite in AlCl 3 aqueous solution is facilitated by hydrothermal treatment . Well-crystallized Ca-Mg-Al LDH crystals are achieved under (Ca + Mg): Al molar ratio = 1:1, pH = 10.5 via a simple co-precipitation method. The maximum utilization efficiencies of Ca 2+ , Mg 2+ from dolomite to LDH are 36.3% and 95.5%, respectively. The possible mechanisms of LDH formation were: 1) the dolomite dissolved in the strong acid solution due to the hydrolysis of AlCl 3 and thus provided Ca 2+ and Mg 2+ ; 2) with addition of NaOH, Al 3+ cations precipitated to form Al(OH) 3 (at 8.3 ≤ pH ≤ 9.3) and then part of the Al(OH) 3 reacted with Ca 2+ and Mg 2+ to form the Ca-Mg-Al LDH; 3) at pH = 10.5, the Al(OH) 3 was transformed as [AlO(OH)] and meanwhile Ca 2+ , Mg 2+ and Al 3+ took part in the formation of Ca-Mg-Al LDH; 4) when pH = 10.6, [AlO(OH)] reacted with NaOH to dissolve into [Al(OH) 4 ]− and the [Al(OH) 4 ]− finally co-precipitated with Ca 2+ and Mg 2+ to form the Ca-Mg-Al LDH during heating for drying.
研究领域:
材料科学
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矿物加工
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无机化学
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环境地球化学
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湿法冶金
✓ 已验证
DOI
高影响因子
ACS Omega
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2019
·
IF 2.584
Yuan Hu,Yuqing Huang,Rongdong Deng,Lin Ma,Wanzhong Yin
In this study, FeSO4·7H2O was used as an auxiliary depressant to improve the selective depression effect on fluorite. Microflotation tests using oleic acid as the collector showed that the pre-addition of FeSO4·7H2O and subsequent addition of sodium silicate (SS) resulted in a stronger selective depression effect on fluorite compared with SS alone. Addition of FeSO4·7H2O reduced the required dosage of SS and had little negative effects on scheelite recovery. The selective depression mechanism of FeSO4·7H2O was investigated in detail. X-ray photoelectron spectroscopy indicated that the difference in the number of surface active sites was the mechanism for improved differential flotation of scheelite from fluorite. The improved depression of fluorite was attributed to both ferrous and sulphate ions. The pre-adsorption of ferrous species increased the number of active sites, enhancing the adsorption of silicate species on the fluorite surface. Simultaneously, sulfate ions were selectively adsorbed on the fluorite surface to form hydrophilic calcium sulfate, reducing the floatability of fluorite.
研究领域:
矿物加工
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浮选化学
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表面化学
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稀有金属提取
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2017
·
IF 2.714
Hao Yi,Yunliang Zhao,Feng Rao,Shaoxian Song
In this work, hydrophobic agglomeration of fine talc particles in aqueous solutions under mechanical conditioning and without any addition of surfactants has been experimentally studied. A method of in-situ measurement of turbidity of flocs suspension in the settlement process has been applied, and the turbidity as a function of settling time has been attempted to fit a certain function so as to assess the hydrophobic agglomeration behaviors. Effects of kerosene dosages, stirring rate, and wettability of talc particles on the hydrophobic agglomeration behaviors have been investigated. The results show that the addition of kerosene can greatly enhance the aggregation of colloidal talc in aqueous suspensions. Besides, the stirring strength and duration make an enormous influence on the aggregation through providing the kinetic energy for overcoming the energy barrier between the approaching particles. It is also found that the wettability of talc is closely related to the aggregation degree. More hydrophobic talc particles show a much stronger aggregation behaviors.
研究领域:
矿物加工
·
胶体科学
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表面化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
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2018
·
IF 3.12
Yubo Tu,Peiwei Han,Lianqi Wei,Xiaomeng Zhang,Bo Yu,Peng Qian,Shufeng Ye
Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction, which are hazardous solid wastes due to the toxic cyanide. Pyrite is one of the main minerals in cyanide tailings. The removal of cyanide adsorbed on pyrite by H 2 O 2 oxidation under alkaline conditions was investigated in this study. It was found that the removal efficiency was positively correlated with pH from 5 to 12, but remained almost constant when pH was higher than 12. The highest cyanide removal efficiency of 91.10% was achieved by adding no less than 0.6 wt.% of H 2 O 2 . Cyanide removal was positively correlated with the CN − adsorption amount between 1.06 and 8.5 mg/g, and temperature between 25 and 85°C. The removal of cyanide adsorbed on pyrite by H 2 O 2 oxidation under alkaline conditions was due to the oxidation of pyrite. Hexacyanoferrate, thiocyanate and sulfate were generated with mole ratios of about 2.03:1.12:3.17 during the cyanide removal.
研究领域:
环境科学
·
矿物加工
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废物处理
·
湿法冶金
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）