Wyniki wyszukiwania - BazTech

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Flotation separation of cassiterite and chlorite using carboxymethyl cellulose as a depressant

Hu Yang, Ying Luo Hong, Zhang Ying, Wei Lu Kuan, Hao Guan Zhen

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 155141

EN

The nature and mechanism of interaction between carboxymethyl cellulose (CMC) with cassiterite (and chlorite surfaces) and their effects on the flotation separation process of cassiterite (from chlorite) were investigated by micro-flotation tests, surface adsorption experiments, zeta potential measurements, solution chemical calculation, infrared spectroscopy, and X-ray photo-electron spectroscopy (XPS). The results from single mineral tests revealed that CMC exhibited good selective inhibition effects with cassiterites and chlorites. When the dosage was 12.5 mg/L at pH 8, cassiterite and chlorite recovery was 92.2% and 6.3%, respectively. The artificial mixed ore test revealed that the flotation separation effect was the best when the dosage of CMC was 6.5 mg/L. Cassiterite used during the studies was 75.1% pure. The recovery was 82.8%. The interaction between CMC and the cassiterite surface led to a shift in the zeta potential toward the negative direction. CMC was weakly adsorbed on the cassiterite surface. There was no significant impact on the subsequent collection of sodium oleate. The concentration of C atom increased post interaction, and the potential shifted toward the negative direction. Characteristic CMC peaks were observed at this point. Hydrogen bonds and weak chemisorption interactions between CMC and chlorite affected the interaction between sodium oleate and the chlorite surface. It also affected the flotation results. The cassiterite and chlorite were separated effectively.

2

Dispersion of sodium phytate on muscovite and the implications for arsenopyrite flotation

Zou Dan, Wang Zhen, Zhao Kaile, Xu Ying

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 154951

EN

The effective flotation separation of sulfides and sliming silicate minerals is always a difficult problem. In this paper, the selective flotation of arsenopyrite from muscovite was studied by using sodium phytate (SP) as dispersant, and the mechanism was investigated through SEM/EDS, zeta potential, FTIR and XPS measurements. Single mineral flotation results showed that with the increasing isoamyl xanthate (IAX) dosage the recovery of arsenopyrite increased, until 8×10−5 mol/L IAX (79.40% recovery, pH=7), after that it decreased slightly. While muscovite floated poorly at any IAX concentration. For the mixed minerals, arsenopyrite recovery was only 54.63% while that of muscovite was 42.70%, which was attributed to the coverage of muscovite on arsenopyrite surface. When 6×10−5 mol/L SP was added into the mixed minerals system, the recovery of arsenopyrite recovered to 68.26% while that of muscovite was 8.48% (approximate the value of the single mineral). SEM/EDS results showed that SP could disperse muscovite and prevented its coverage on arsenopyrite surface. Zeta potential results showed that the electrokinetic potential of muscovite and arsenopyrite decrease from -26.60mV to -39.01 mV and from -26.90 mV to -27.84 mV at pH=7, respectively. It was obvious that the negatively charged phytate ions selectively adsorbed on the surface of muscovite. FTIR and XPS resulted co-proved the chemisorption of SP with active sites on muscovite while arsenopyrite spectrum did not change significantly, which was consistent with flotation and zeta potential results. The selective adsorption of SP on muscovite compared to arsenopyrite was responsible for the effective separation of them.

3

Constitutive allelochemicals from Stratiotes aloides L. affect both biomass and community structure of phytoplankton

Kufel L.

Polish Journal of Ecology

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2007

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Vol. 55, nr 2

387-393

EN

The paper presents the results of a study on allelopathic effect of extracts from Stratiotes aloides on natural lake phytoplankton communities grown outdoor in 40 l containers under natural light conditions. The water and plants were taken from an oxbow lake in spring (when S. aloides plants were submerged) and in summer (when plants were floating on lake water surface). Water extracts were prepared from fresh healthy leaves obtained on both sampling occasions. Control containers were supplemented with N and P in amounts similar to those introduced to experimental containers with macrophyte extracts. That way the experimental set up excluded the possibility of phytoplankton limitation by nutrients. Under such conditions the extracts from S. aloides strongly reduced phytoplankton biomass measured as the concentration of chlorophyll a (from 370 to 141 mg chl. a m[^-3] in spring and from 266 to 50 mg chl. a m[^-3] in summer). The inhibition of phytoplankton growth was indirectly confirmed by higher concentrations of available nutrients in experimental versus control containers. The extracts affected also the spring phytoplankton community structure by selective inhibition of diatoms and, to a less extent, of green algae and Cryptophyceae. Similar response of phytoplankton biomass to extracts obtained from submerged and floating S. aloides might suggest that allelochemicals were the constitutive part of macrophyte tissue and their production was not iduced by competition between macrophyte and algae.