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1
Content available Effect of particle shape properties on selective separation of chromite from serpentine by flotation
Guven Onur, Serdengecti M. Tayhan, Tunc Berivan, Ozdemir Orhan, Karaagaclioglu Ibrahim E., Çelik Mehmet S.
Physicochemical Problems of Mineral Processing
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2020
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Vol. 56, iss. 5
818--828
EN
Although many studies have been conducted on the morphological variations and its effects on flotation recoveries of a single mineral system, a systematic study for the flotation behavior of mixtures of minerals has not dwelled much. In this study, th flotation behavior of chromite and serpentine minerals was investigated to distinguish and isolate the contribution of morphology in single and binary systems. For this purpose, the shape analyses for the minerals ground as single and mixture were performed, and their flotation behaviors determined with the micro-flotation experiments. Additionally, the zeta potential measurements were carried out in the presence of sodium oleate as a collector. The shape analysis of the ground samples showed that while the roundness values of chromite and serpentine (gangue) minerals as single were quite different, the particle shape of chromite favored serpentine in the mixture system which in turn suggested that the mineral with the high hardness value dominates the shape characteristics in binary grinding conditions. Accordingly, while the flotation characteristics of chromite in the mixture followed the same trend with the flotation of a single chromite system as a function of particle shape, almost a reverse trend was obtained for the shape and flotation of serpentine in the mixture compared to a single serpentine system. Thus, at roundness values of chromite particles from 0.797 to 0.732, the flotation recoveries of chromite in the mixture increased from 51.0% to 75.4%. On the other hand, likewise chromite, the flotation recoveries of serpentine increased from 20.0% to 37.3% proportional to the roundness range of 0.757 and 0.709. These findings in turn showed that the grinding conditions dictate the soft component to be monitored by the harder and denser component which dominates the angularity and floatability of the mixture.
2
Content available Inhibiting effect of citric acid on the floatability of serpentine activated by Cu(II) and Ni(II) ions
Huang Jun-wei, Zhang Cheng-qiang
Physicochemical Problems of Mineral Processing
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2019
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Vol. 55, iss. 4
960--968
EN
The laboratory researches about the inhibiting effect of citric acid on the flotation performance of serpentine activated by Cu2+ and Ni2+ were carried out through micro flotation tests, zeta potential measurements, collector adsorption capacity measurements and solution chemistry analysis. The flotation results showed that Cu2+ and Ni2+ could remarkably activate the flotation of serpentine when the pH value was more than 6, however, this activation could be effectively weakened by adding citric acid. Zeta potential measurement and adsorption capacity measurement indicated that the presence of citric acid could prevent the adsorption of Cu2+ and Ni2+, and therefore reduce the adsorption amount of potassium butyl xanthate on serpentine surface. Furthermore, solution chemical analysis of the flotation system showed that copper hydroxide Cu(OH)2(s) and the nickel hydroxide Ni(OH)2(s) were the main component in the pH range of 9 to 10, which adsorbed onto serpentine surface and made it activated; while the citric acid could effectively prohibit the formation of these metal hydroxide in slurry so as to inhibit the activation impact.
3
Content available Selective agglomeration of magnetite in entlandite-serpentine system and implication for their separation
Lu J., Yuan Z., Liu J., Li L., Wang N., Meng Q.
Physicochemical Problems of Mineral Processing
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2017
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Vol. 53, iss. 2
943--955
EN
In nickel sulfide processing, magnesium silicates (serpentines) can easily form slime coatings or hetero-aggregation on pentlandite surfaces, and hence decrease the pentlandite flotation rate and recovery. In this work, magnetic separation of pentlandite from serpentine using selective magnetic coating through adding magnetite fines as magnetic seeds was investigated. Interactions of magnetite-pentlandite and magnetite-serpentine were calculated by the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory. The results show that the interaction of magnetite-pentlandite was obviously stronger than that of magnetite-serpentine with an external weak magnetic field (4776 A/m-1). Therefore, fine magnetite fractions selectively adhered to the pentlandite surfaces and enhanced its magnetism, resulting in being separated from serpentine by magnetic separation, which was further verified by magnetic coating-magnetic separation and SEM observations.
4
Content available Interaction between mineral particles during ascharite flotation process and direct force measurement using AFM
Li Z., Han Y., Li Y., Gao P.
Physicochemical Problems of Mineral Processing
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2017
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Vol. 53, iss. 2
1161--1174
EN
Interaction between mineral particles during ascharite flotation was investigated by flotation, zeta potential, Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, atomic force microscope (AFM) and SEM-EDS tests. Flotation results showed that the ascharite recovery decreased significantly in the presence of serpentine. In order to improve the ascharite recovery, negative charged quartz was used to limit the detrimental effect of serpentine on ascharite flotation in this research. The effect of quartz on improving ascharite recovery was attributed to the particle surface interactions. The DLVO theory was applied to study the particles interaction in the aqueous solution. The fitting curves showed that serpentine could attach to the surface of quartz easily, and quartz would be well dispersed with ascharite. Therefore, quartz can improve the ascharite flotation performance effectively by interaction between particles. Zeta potential tests showed the opposite charges on the surfaces of mineral particles, which was the basic reason leading to particles interaction. The force measurement results of AFM indicated that the attraction force existed between serpentine and ascharite, as well as serpentine and quartz, but the force between quartz and ascharite was repulsive. The DLVO theory was in a good agreement with the results of AFM. Eventually, particles coating were observed by SEM-EDS, which supported the results of DLVO theory and AFM measurements. During the flotation process, addition of quartz would lead to attachment of serpentine to the quartz surface, so the adverse effect of serpentine on decreasing floatability of ascharite was weakened.
5
Content available Dispersive effect of low molecular weight sodium polyacrylate on pyrite-serpentine flotation system
Zhao K., Yan W., Wang X., Gu G., Deng J., Zhou X., Hui B.
Physicochemical Problems of Mineral Processing
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2017
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Vol. 53, iss. 2
1200--1213
EN
In this work, the dispersive effect of low molecular weight sodium polyacrylate (PAAS) on serpentine, and its dispersion mechanism were systematically investigated through zeta potential measurements, micro and batch flotation as well as adsorption tests. At pH 5, where flotation of iron sulphide was routinely performed, pyrite and serpentine minerals were oppositely charged, and therefore they were attracted to each other. Slime coatings of serpentine adhered to the surface of pyrite, decreasing the adsorption density of a collector on the pyrite surface, but also reducing the flotation recovery. PAAS increased the flotation recovery of pyrite by promoting dispersion between pyrite and serpentine. The effective flotation separation of pyrite from the refractory iron sulphide ore was possible by using PAAS as a dispersant. Anionic PAAS adjusted the surface potential of serpentine through adsorption on the serpentine surface and changed the interaction between pyrite and serpentine particles from attractive to repulsive, and then dispersed pyrite and serpentine.
6
Content available Concentration of chromite by means of magnetic carrier using sodium oleate and other reagents
Ucbas Y., Bozkurt V., Bilir K., Ipek H.
Physicochemical Problems of Mineral Processing
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2014
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Vol. 50, iss. 2
767--782
EN
Chromite recovery was studied using a magnetic carrier technology. Heavy media grade magnetite was used as the magnetic carrier. The effect of various reagents such as sodium oleate (NaOl) as a collector and carboxymethyl cellulose (CMC) as well as quebracho tannin as depressants on chromite removal was investigated. The effects of pH and reagent dosages were also determined. First, the zeta potential measurements were performed for different minerals in the absence and presence of NaOl, and then magnetic carrier tests were carried out under conditions based on zeta potential measurements. The magnetic carrier tests performed in the case of individual minerals (i.e. single minerals) showed that chromite (recovery of 95.1%) could be separated from serpentine (recovery of 3.2%) whereas it could not be separated from olivine. The best chromite concentrates containing 42.1% Cr2O3 were obtained with a 76% recovery from a synthetic mixtures of chromite and serpentine under optimum test conditions, that is at pH 10.5, 5.10–5 M NaOl, 20 g/Mg CMC, 0.5 g magnetite and 500 g/Mg kerosene (the feed contained 27% Cr2O3). Slime tailings of Turkish Maadin Company, Kavak Chrome Concentrating Plant in Eskisehir, which contain fine chromite, serpentine and olivine, were also investigated. It was found that chromite could not be satisfactorily recovered from the original slime sample in the presence and absence of NaOl by using the magnetic carrier technology. Additional FTIR studies performed with the investigated minerals showed that NaOl adsorption on chromite was greater than that on serpentine and magnetite minerals. It was also found that NaOl adsorption on serpentine is significantly reduced in the presence of magnetite while it increases only slightly on chromite.
7
Content available Accumulation of Heavy Metals by Silene vulgaris Occurring on Serpentine Waste Dump in Grochow (Lower Silesia)
Koszelnik-Leszek A.
Ecological Chemistry and Engineering. A
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2012
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Vol. 19, nr 4-5
411-420
EN
The investigation involved serpentine waste dump in Grochow (Lower Silesia).Botanical composition of analyzed serpentine dumping ground was poor since in the areas subjected to examination there were designated only 30 vascular plant species classified mainly to three botanical families – Poaceae, Fabaceae and Asteraceae. Dominant species on dumping ground in Grochow was the only recognized species representing Caryophyllaceae – Silene vulgaris. Analysis of soils material proved that total contents of nickel, chromium, manganese and cobalt were higher than average quantities of these metals in soil environment. Mobile forms, available for plants, provided, in most cases, for only a small per cent of their total forms. In plant material originating from serpentine dumping ground their were recorded high concentrations of Ni, Cr and Co in comparison with their natural amounts. Concentrations of all the examined metals were higher in underground parts of Silene vulgaris than in aboveground parts.
PL
Badaniami objęto hałdę odpadów serpentynitowych w Grochowie (Dolny Śląsk). Skład florystyczny analizowanego zwałowiska był ubogi. Na badanych powierzchniach stwierdzono jedynie 30 gatunków roślin naczyniowych, należących głównie do trzech rodzin botanicznych . Gatunkiem dominującym na zwałowisku w Grochowie był jedyny rozpoznany na jego obszarze przedstawiciel Caryophyllaceae - Silene vulgaris. Analiza materiału glebowego wykazała, że ogólne zawartości niklu, chromu, manganu i kobaltu były wyższe od przeciętnych ilości tych metali w środowisku glebowym. Formy mobilne, dostępne dla roślin stanowiły we wszystkich przypadkach tylko niewielki procent ich form całkowitych. W materiale roślinnym pochodzącym ze zwałowiska stwierdzono wysokie w porównaniu z naturalnymi zawartości Ni, Cr i Co. Koncentracje wszystkich analizowanych metali były wyższe w częściach podziemnych Silene vulgaris niż w częściach nadziemnych.
8
Content available remote Selective flocculation behavior of chromite and serpentine
Beklioglu B., Arol A. I.
Physicochemical Problems of Mineral Processing
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2004
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Vol. 38
103-112
EN
Application of selective flocculation using starch to separate chromite from serpentine has been investigated. It was determined that starch has a specific affinity towards chromite which can be exploited in selective flocculation. However, it was found that this could only be achieved when the amount of serpentine in the chromite-serpentine mixture is below 30% by weight and in the presence of a dispersant such as sodium silicate or ultrasonic treatment of the pulp.
PL
Metoda selektywnej flokulacji z użyciem skrobi jako flokulanta, została użyta do oddzielenia chromitu od serpentynitu. Zostało ustalone, na podstawie badań, że skrobia wykazuje specyficzne powinowactwo do chromitu, który dzięki temu może ulec selektywnej flokulacji. Okazało się jednak, że selektywny rozdział jest możliwy do osiągnięcia w warunkach, gdy ilość serpentynitu w chromicie nie przekracza 30% wagowych. Proces separacji został zrealizowany w obecności dysperganta - krzemianu sodu, a zawiesina była traktowana ultradźwiękami.
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