Autor: Subramanian, S. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Selective dispersion-flocculation and flotation studies on a siliceous copper ore
Autorzy:: Mweene, L.
Subramanian, S.
Powiązania:: https://bibliotekanauki.pl/articles/109546.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: flocculation
adsorption
zeta potential
dispersion
chalcopyrite flotation
Opis:: A low-grade copper ore from Mpanda Mineral Field (MMF), Tanzania containing 0.90% Cu, 10.40% Fe and 58.3% SiO2 was subjected to beneficiation adopting selective dispersion, flocculation and flotation techniques. Based on the mineralogical characterization of the sample chalcopyrite, pyrite and quartz were identified as the major minerals. The isoelectric point of MMF ore was observed to be at pH 2.7, signifying that the ore was highly siliceous. The addition of sodium trisilicate and xanthan gum shifted the zeta potential of ore to more electronegative values. Adsorption of xanthan gum on chalcopyrite and silica indicated that the maximum adsorption was at pH 2.3 for chalcopyrite and the adsorption isotherm exhibited L2 type of the Giles classification. On the contrary, no adsorption of xanthan gum on silica was observed. The ground ore was selectively dispersed and flocculated at pH 9.7 using 30 ppm of sodium trisilicate and 30 ppm of xanthan gum. The grade of CuFeS2 was improved to 19.8% after 3 desliming stages. Flotation of the flocculated portion was carried out at pH 10.30 using 30 g/t of potassium amyl xanthate and potassium ethyl xanthate (1:1) , 40 g/t of Na2S as a sulphidising agent and methyl iso-butyl carbinol (MIBC) as a frother yielding a rougher concentrate with silica and chalcopyrite grades of 8.4% and 23.5% respectively with corresponding recoveries of 4.8% and 92.8% respectively. Additionally, rougher concentrate was subjected to cleaner flotation yielding silica and chalcopyrite grades of 1.8% and 29.2 % respectively and with recoveries of 1.2% and 89.1% respectively.
Źródło:: Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1282-1291
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Study on the Change in Characteristics of Ring Yarn during Post Spinning and Yarn Dyeing Operations
Badanie zmian właściwości przędz pierścieniowych podczas przędzenia i barwienia
Autorzy:: Saravanan, A. R.
Subramanian, S.
Powiązania:: https://bibliotekanauki.pl/articles/231968.pdf
Data publikacji:: 2018
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:: yarn abrasion
cone winding
hairiness
ring spinning
ring yarn
singeing
yarn imperfections
yarn tenacity
yarn dyeing
ścieranie przędzy
nawijanie stożka
włochatość
wirowanie pierścienia
przędza pierścieniowa
niedoskonałości przędzy
wytrzymałość przędzy
barwienie przędzy
Opis:: The origin of yarn hairiness has been attributed to the escape of fibres from the twisting action from within the spinning triangle. The protruding fibres entangle themselves due to the rubbing of yarn with parts of the machinery during post spinning operations and form thin places, thick places and neps. In this study, cotton combed yarns were produced by removing 14, 16 and 18% of the noil at the comber. These samples were dyed before and after singeing. The hairiness, imperfections and tenacity of the yarns were measured. The results revealed that an increase in comber noil causes a decrease in imperfections at the ring bobbin stage. The imperfections changed at different stages of post spinning operations and dyeing, and finally the difference was not appreciable, especially when the noil % was extracted beyond a certain level. The tenacity of yarn decreased when the ring bobbin was converted into a cone form, singed and dyed. Removal of a higher level of comber noil or singeing did not make a significant difference at the dyed yarn stage, although there was difference at the ring bobbin and cone stages.
Pochodzenie włochatości przędzy przypisuje się ucieczce włókien podczas procesu skręcania. Wystające włókna splątują się w wyniku styczności przędzy z częściami maszyn podczas operacji przędzenia i tworzą pocienienia i wzgrubienia. W pracy wytworzono przędze czesankowe, które następnie barwiono przed i po opalaniu. Zmierzono włochatość, niedoskonałości i wytrzymałość przędz. Wyniki ujawniły, że niedoskonałości przędz zmianiły się na różnych etapach operacji po przędzeniu i farbowania, a na końcu różnica nie była znacząca. Wytrzymałość przędzy zmniejszyła się, gdy cewka pierścieniowa została przekształcona w postać stożka. Usunięcie wyższego poziomu zgrubienia lub uskoki nie spowodowało istotnej różnicy w poziomie wybarwienia przędzy.
Źródło:: Fibres & Textiles in Eastern Europe; 2018, 3 (129); 35-39
1230-3666
2300-7354
Pojawia się w:: Fibres & Textiles in Eastern Europe
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Utility of Chromobacterium violaceum SUK1a, an indigenous bacterial isolate for the bioremediation of Cr(VI)
Autorzy:: Prabhakaran, D. C.
Krishnan, S.
Ramamurthy, P. C.
Sivry, Y.
Quantin, C.
Subramanian, S.
Powiązania:: https://bibliotekanauki.pl/articles/109867.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: biosorption
bioremediation
chromium
bioreduction
Chromobacterium violaceum SUK1a
Opis:: The potential of an indigenous bacterial strain, Chromobacterium violaceum SUK1a, isolated from surface water samples collected from Sukinda Valley in Odisha, India, has been evaluated for the first time for the bioremediation of toxic hexavalent chromium (Cr(VI)) ions. The isolate was assessed for its Cr(VI) biosorption efficiency and the various parameters affecting the biosorption process were evaluated. A maximum Cr(VI) biosorption of about 50% was obtained, and the residual chromium was in the form of less toxic Cr(III). The Gibbs free energy of biosorption was determined to be -26.3 kJ/mol, suggestive of a chemisorption process. Additionally, the Cr(VI) biosorption by the isolate followed pseudo second order kinetics. FTIR spectral studies indicated that the surface functional groups present on the bacterial isolate such as, carboxyl, hydroxyl, amino, and phosphate groups were involved in the complexation of chromium ions with the bacterial cells. X-ray photoelectron spectroscopic studies on Cr(VI) interacted bacterial cells revealed an additional peak corresponding to Cr(III) in the Cr(2p) spectra. The surface charge of the bacterial cells subsequent to interaction with Cr(VI) were less negative compared to the pristine cells, which further substantiated the bioreduction of Cr(VI) to Cr(III). The bioremediation mechanism of Cr(VI) by the bacterial isolate is delineated to be governed by both biosorption and bioreduction processes under metabolism independent conditions. The results obtained indicate that the isolate can be a promising candidate for Cr(VI) bioremediation applications.
Źródło:: Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1266-1281
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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