In this work, the properties of alkali silicate geopolymer type materials and diatomite as additi... more In this work, the properties of alkali silicate geopolymer type materials and diatomite as additive to fly coal ash was investigated using thermic coal plant's fly ash in alkaline solution. The reacted products of alumino-silicate geopolymers using fly ash plus diatomite were pseudo-amorphous aluminosilicate gel and calcite and their mechanical and thermal properties were evaluated by the addition of diatomite. The compressive strength of this geopolymer is similar to that of the Portland cement mortar of PC20 (± 20 %) when cured for 28 days while the density and thermal properties are much lower that indicates the insulator properties. Alkaline solution was produced by NaOH in different concentrations to determine the least alkaline solution molarity in the range of 1 M, 3 M and 5 M. The characterization of geopolymers were done by using XRD for phase analysis, SEM for surface and morphological evaluation, compression tests for mechanical properties and transient plane source thermal analysis for thermal insulation properties. The results showed that, 1 M of NaOH alkaline solution and 10 wt.% diatomite addition can provide enough strength of 18 MPa which is a good candidate for constructional materials. The thermal conductivity coefficient of 10 wt.% diatomite added geopolymer was evaluated as 0.0018 W/m⋅K which can also be a good candidate for insulator materials to be used in green lateral wall production.
Physicochemical Problems of Mineral Processing, 2014
Recovery of gangue pyrite and its accidental activation are vital issues in flotation of complex ... more Recovery of gangue pyrite and its accidental activation are vital issues in flotation of complex sulfide ores. This work was performed by cyclic voltammetry (CV) and flotation tests to elucidate applicability of ovalbumin (OVA) as depressant for pyrite. The synergetic effect of metal ions in addition to its possible use in case of accidental activation by metal ions. CV tests stated that OVA adsorbed irreversibly on pyrite, and restricted electron transfer up to moderately oxidizing potentials due to electrostatic interaction together with weak hydrophobic interactions. At highly oxidizing potentials, adsorption occurred through electrochemical mechanisms through formation of metal-OVA chelates. Rate of pyrite depression with OVA was found to be potential dependent reaching its peak point around moderately oxidizing potentials both in absence and presence of metal ions. Electrochemically active metals display synergetic effect with OVA on pyrite depression, whereas noble metals activate pyrite and reduced depressing potency of OVA.
Bu calismada, Artvin-Murgul cevher yatagindan alinan pirit orneginin toplayicisiz ortamda Kuebra ... more Bu calismada, Artvin-Murgul cevher yatagindan alinan pirit orneginin toplayicisiz ortamda Kuebra (quebracho) ile etkilesiminin, donusumlu voltametri deneyleri ile aydinlatilmasi ve farkli potansiyellerde bu reaktifin pirit flotasyonuna etkisinin ortaya konulmasi amaclanmistir.Oncelikle pirit orneklerinin donusumlu voltmetre (CV) yontemini kullanarak, farkli kosullarda piritin elektrokimyasal davranisi incelenmis, mineral yuzeyinde gerceklesen redoks tepkimeleri tahmin edilmistir. Elde edilen bulgular isiginda belirlenen potansiyel degerlerinde, yuzeyde olusan redoks bilesiklerinin piritin yuzebilirligine etkisinin belirlenmesi amaciyla flotasyon deneyleri yapilmistir. Genel olarak indirgen potansiyellerde dusuk verim elde edilirken 200 mV’un uzerinde ise verimde onemli bir artis oldugu gozlenmistir. Notr ve alkali ortamda farkli pH degerlerinde yapilan flotasyon deneyleri sonucunda en iyi verim degerlerine pH 6.97’de orta ve yukseltgen potansiyellerde ulasilmistir. Pirit oksidasyonu...
In this work, the properties of alkali silicate geopolymer type materials and diatomite as additi... more In this work, the properties of alkali silicate geopolymer type materials and diatomite as additive to fly coal ash was investigated using thermic coal plant’s fly ash in alkaline solution. The reacted products of alumino-silicate geopolymers using fly ash plus diatomite were pseudo-amorphous aluminosilicate gel and calcite and their mechanical and thermal properties were evaluated by the addition of diatomite. The compressive strength of this geopolymer is similar to that of the Portland cement mortar of PC20 (± 20 %) when cured for 28 days while the density and thermal properties are much lower that indicates the insulator properties. Alkaline solution was produced by NaOH in different concentrations to determine the least alkaline solution molarity in the range of 1 M, 3 M and 5 M. The characterization of geopolymers were done by using XRD for phase analysis, SEM for surface and morphological evaluation, compression tests for mechanical properties and transient plane source therm...
Bu çalışmada, Sivas Kangal Termik Santrali’nden edinilmiş uçucu külden yapılan alkali aktivasyon ... more Bu çalışmada, Sivas Kangal Termik Santrali’nden edinilmiş uçucu külden yapılan alkali aktivasyon yani jeopolimerleşmenin ardından, farklı sıcaklıklarda sinterlenmesi ile üretilen numunelerin mekanik özellikleri, toz özellikleri, termal özellikleri ve faz özellikleri tartışılmıştır. Mekanik özellikler için basma testi, termal özellikler için geçirgen plaka kaynağı ölçümü, yüzey ve toz özellikleri için taramalı elektron mikroskobu ve faz analizi için X-ışınları difraksiyonu kullanılmıştır. Yapılan çalışmalarda kolay bulunan ve silika kaynağı da olabilen bir alkali olan Na2SiO3 farklı molaritelerde kullanılmış ve özellikleri incelenmiştir. Uçucu külün hem jeopolimer olarak kullanılabilirliği, hem de sinterlenmiş malzemenin yüzey plakası olarak kullanılabilirliğinin olduğu sonucuna varılmıştır. Basma mukavemeti 10 MPa, termal iletkenliği 0.0006 W/m.K, belirlenen fazlar ise kalsiyum silikat, kalsiyum aluminate, amorf silika ve magnezyum alüminat ve sinterleme ürünü olan camsı kyanite yan...
Geopolymer structures are a relatively new family of un-fired ceramics that are produced by alkal... more Geopolymer structures are a relatively new family of un-fired ceramics that are produced by alkaline slurry of mixed alumina silicate-based materials. One of the most abundant geopolymer-forming powders is the fly ash. Fly ash is a waste product of thermic coal plants, which produce electricity by coal burning. Fly ashes contain mostly Ca, Al, Si and Fe oxide mixtures and compounds formed during the burning process, followed by sedimentation. The standardization is made by SiO2 content. Class C ash has low silica content (<50 wt.%) and class F ash has a higher silica content (>50 wt.%). The fly ash, studied in this work, was obtained from Kangal Coal Plant. The NaOH was used as the geopolymer binder and curing was performed at 80% relative humidity, at 40 • C in sealed plastic molds. The obtained cylinders were aged for one week before releasing from molds. pH dependent degradation was used to determine the ionic exchange of geopolymers into the solution. Afterwards, XRD and SEM were done to detect the structural changes of geopolymers.
Chalcopyrite (CuFeS 2) is commonly used ore in production of copper, but leaching of this ore is ... more Chalcopyrite (CuFeS 2) is commonly used ore in production of copper, but leaching of this ore is very slow and inefficient due to "passivation" during leaching at atmospheric conditions. In this study, in order to overcome drawbacks of the passivation layers, the concentrate supplied from Eti Bakır A.Ş. Küre Plant in Turkey was roasted at 600 °C for 1 h and after leached. Box-Wilson procedure of statistical experimental design was utilized to identify the effects of significant leaching variables for instance leaching time (X 1 ; 10-120 min), solid/liquid ratio (X 2 ; 0.01-0.20), and H 2 SO 4 concentration (X 3 ; 0.01-1.00 M) on Cu extraction (%) from roasted concentrate and was tried to be optimized. The coefficients of response functions have been calculated by regression analysis, and the estimates have been found to be well in line with the experimental outcomes. The optimal leaching parameters, time, solid/liquid rate and H 2 SO 4 concentration were determined as 115 min, 0.116, and 0.71 M, respectively, and the highest Cu extraction (%) value was calculated as 92.45%.
Abstract Batch flotation experiments were conducted using a bituminous coal. It was found out tha... more Abstract Batch flotation experiments were conducted using a bituminous coal. It was found out that pulp density and especially impeller speed had significant influences on coal flotation performance, selectivity and rate. Products with lower ash content were obtained ...
Transactions of Nonferrous Metals Society of China, 2013
Ovalbumin (OVA), chicken egg albumin, is an environmentally friendly, non-toxic, cheap surface ac... more Ovalbumin (OVA), chicken egg albumin, is an environmentally friendly, non-toxic, cheap surface active agent. It has electrochemically active sulfhydryl residues in molecular structure. OVA adsorption on pyrite as an alternative depressant was investigated by cyclic voltammetry, FTIR spectroscopy and flotation. Tests were conducted in a wide potential range in alkaline pH to clarify the role of electrochemical condition on the adsorption mechanisms and the rate of depression. In the absence of OVA, the floatability reached its maxima around slightly oxidizing condition. Beyond the range, it decreased presumably due to the formation of Fe-oxyhydroxides together with the hydrophilic S-containing species. OVA−pyrite interaction occurred in the whole examined potential range. Depressing effect of OVA increased gradually from reducing to slightly oxidizing potential, open circuit potential (OCP) of pyrite, mainly due to weak conformational changes in OVA molecules together with the hydrophobic interaction around OCP. The rate of depression reached its maxima at moderately oxidizing potentials, which was referred to electrostatic attraction. This level was almost kept at higher potentials owing to OVA adsorption as metal−chelates.
In this work, the properties of alkali silicate geopolymer type materials and diatomite as additi... more In this work, the properties of alkali silicate geopolymer type materials and diatomite as additive to fly coal ash was investigated using thermic coal plant's fly ash in alkaline solution. The reacted products of alumino-silicate geopolymers using fly ash plus diatomite were pseudo-amorphous aluminosilicate gel and calcite and their mechanical and thermal properties were evaluated by the addition of diatomite. The compressive strength of this geopolymer is similar to that of the Portland cement mortar of PC20 (± 20 %) when cured for 28 days while the density and thermal properties are much lower that indicates the insulator properties. Alkaline solution was produced by NaOH in different concentrations to determine the least alkaline solution molarity in the range of 1 M, 3 M and 5 M. The characterization of geopolymers were done by using XRD for phase analysis, SEM for surface and morphological evaluation, compression tests for mechanical properties and transient plane source thermal analysis for thermal insulation properties. The results showed that, 1 M of NaOH alkaline solution and 10 wt.% diatomite addition can provide enough strength of 18 MPa which is a good candidate for constructional materials. The thermal conductivity coefficient of 10 wt.% diatomite added geopolymer was evaluated as 0.0018 W/m⋅K which can also be a good candidate for insulator materials to be used in green lateral wall production.
Physicochemical Problems of Mineral Processing, 2014
Recovery of gangue pyrite and its accidental activation are vital issues in flotation of complex ... more Recovery of gangue pyrite and its accidental activation are vital issues in flotation of complex sulfide ores. This work was performed by cyclic voltammetry (CV) and flotation tests to elucidate applicability of ovalbumin (OVA) as depressant for pyrite. The synergetic effect of metal ions in addition to its possible use in case of accidental activation by metal ions. CV tests stated that OVA adsorbed irreversibly on pyrite, and restricted electron transfer up to moderately oxidizing potentials due to electrostatic interaction together with weak hydrophobic interactions. At highly oxidizing potentials, adsorption occurred through electrochemical mechanisms through formation of metal-OVA chelates. Rate of pyrite depression with OVA was found to be potential dependent reaching its peak point around moderately oxidizing potentials both in absence and presence of metal ions. Electrochemically active metals display synergetic effect with OVA on pyrite depression, whereas noble metals activate pyrite and reduced depressing potency of OVA.
Bu calismada, Artvin-Murgul cevher yatagindan alinan pirit orneginin toplayicisiz ortamda Kuebra ... more Bu calismada, Artvin-Murgul cevher yatagindan alinan pirit orneginin toplayicisiz ortamda Kuebra (quebracho) ile etkilesiminin, donusumlu voltametri deneyleri ile aydinlatilmasi ve farkli potansiyellerde bu reaktifin pirit flotasyonuna etkisinin ortaya konulmasi amaclanmistir.Oncelikle pirit orneklerinin donusumlu voltmetre (CV) yontemini kullanarak, farkli kosullarda piritin elektrokimyasal davranisi incelenmis, mineral yuzeyinde gerceklesen redoks tepkimeleri tahmin edilmistir. Elde edilen bulgular isiginda belirlenen potansiyel degerlerinde, yuzeyde olusan redoks bilesiklerinin piritin yuzebilirligine etkisinin belirlenmesi amaciyla flotasyon deneyleri yapilmistir. Genel olarak indirgen potansiyellerde dusuk verim elde edilirken 200 mV’un uzerinde ise verimde onemli bir artis oldugu gozlenmistir. Notr ve alkali ortamda farkli pH degerlerinde yapilan flotasyon deneyleri sonucunda en iyi verim degerlerine pH 6.97’de orta ve yukseltgen potansiyellerde ulasilmistir. Pirit oksidasyonu...
In this work, the properties of alkali silicate geopolymer type materials and diatomite as additi... more In this work, the properties of alkali silicate geopolymer type materials and diatomite as additive to fly coal ash was investigated using thermic coal plant’s fly ash in alkaline solution. The reacted products of alumino-silicate geopolymers using fly ash plus diatomite were pseudo-amorphous aluminosilicate gel and calcite and their mechanical and thermal properties were evaluated by the addition of diatomite. The compressive strength of this geopolymer is similar to that of the Portland cement mortar of PC20 (± 20 %) when cured for 28 days while the density and thermal properties are much lower that indicates the insulator properties. Alkaline solution was produced by NaOH in different concentrations to determine the least alkaline solution molarity in the range of 1 M, 3 M and 5 M. The characterization of geopolymers were done by using XRD for phase analysis, SEM for surface and morphological evaluation, compression tests for mechanical properties and transient plane source therm...
Bu çalışmada, Sivas Kangal Termik Santrali’nden edinilmiş uçucu külden yapılan alkali aktivasyon ... more Bu çalışmada, Sivas Kangal Termik Santrali’nden edinilmiş uçucu külden yapılan alkali aktivasyon yani jeopolimerleşmenin ardından, farklı sıcaklıklarda sinterlenmesi ile üretilen numunelerin mekanik özellikleri, toz özellikleri, termal özellikleri ve faz özellikleri tartışılmıştır. Mekanik özellikler için basma testi, termal özellikler için geçirgen plaka kaynağı ölçümü, yüzey ve toz özellikleri için taramalı elektron mikroskobu ve faz analizi için X-ışınları difraksiyonu kullanılmıştır. Yapılan çalışmalarda kolay bulunan ve silika kaynağı da olabilen bir alkali olan Na2SiO3 farklı molaritelerde kullanılmış ve özellikleri incelenmiştir. Uçucu külün hem jeopolimer olarak kullanılabilirliği, hem de sinterlenmiş malzemenin yüzey plakası olarak kullanılabilirliğinin olduğu sonucuna varılmıştır. Basma mukavemeti 10 MPa, termal iletkenliği 0.0006 W/m.K, belirlenen fazlar ise kalsiyum silikat, kalsiyum aluminate, amorf silika ve magnezyum alüminat ve sinterleme ürünü olan camsı kyanite yan...
Geopolymer structures are a relatively new family of un-fired ceramics that are produced by alkal... more Geopolymer structures are a relatively new family of un-fired ceramics that are produced by alkaline slurry of mixed alumina silicate-based materials. One of the most abundant geopolymer-forming powders is the fly ash. Fly ash is a waste product of thermic coal plants, which produce electricity by coal burning. Fly ashes contain mostly Ca, Al, Si and Fe oxide mixtures and compounds formed during the burning process, followed by sedimentation. The standardization is made by SiO2 content. Class C ash has low silica content (<50 wt.%) and class F ash has a higher silica content (>50 wt.%). The fly ash, studied in this work, was obtained from Kangal Coal Plant. The NaOH was used as the geopolymer binder and curing was performed at 80% relative humidity, at 40 • C in sealed plastic molds. The obtained cylinders were aged for one week before releasing from molds. pH dependent degradation was used to determine the ionic exchange of geopolymers into the solution. Afterwards, XRD and SEM were done to detect the structural changes of geopolymers.
Chalcopyrite (CuFeS 2) is commonly used ore in production of copper, but leaching of this ore is ... more Chalcopyrite (CuFeS 2) is commonly used ore in production of copper, but leaching of this ore is very slow and inefficient due to "passivation" during leaching at atmospheric conditions. In this study, in order to overcome drawbacks of the passivation layers, the concentrate supplied from Eti Bakır A.Ş. Küre Plant in Turkey was roasted at 600 °C for 1 h and after leached. Box-Wilson procedure of statistical experimental design was utilized to identify the effects of significant leaching variables for instance leaching time (X 1 ; 10-120 min), solid/liquid ratio (X 2 ; 0.01-0.20), and H 2 SO 4 concentration (X 3 ; 0.01-1.00 M) on Cu extraction (%) from roasted concentrate and was tried to be optimized. The coefficients of response functions have been calculated by regression analysis, and the estimates have been found to be well in line with the experimental outcomes. The optimal leaching parameters, time, solid/liquid rate and H 2 SO 4 concentration were determined as 115 min, 0.116, and 0.71 M, respectively, and the highest Cu extraction (%) value was calculated as 92.45%.
Abstract Batch flotation experiments were conducted using a bituminous coal. It was found out tha... more Abstract Batch flotation experiments were conducted using a bituminous coal. It was found out that pulp density and especially impeller speed had significant influences on coal flotation performance, selectivity and rate. Products with lower ash content were obtained ...
Transactions of Nonferrous Metals Society of China, 2013
Ovalbumin (OVA), chicken egg albumin, is an environmentally friendly, non-toxic, cheap surface ac... more Ovalbumin (OVA), chicken egg albumin, is an environmentally friendly, non-toxic, cheap surface active agent. It has electrochemically active sulfhydryl residues in molecular structure. OVA adsorption on pyrite as an alternative depressant was investigated by cyclic voltammetry, FTIR spectroscopy and flotation. Tests were conducted in a wide potential range in alkaline pH to clarify the role of electrochemical condition on the adsorption mechanisms and the rate of depression. In the absence of OVA, the floatability reached its maxima around slightly oxidizing condition. Beyond the range, it decreased presumably due to the formation of Fe-oxyhydroxides together with the hydrophilic S-containing species. OVA−pyrite interaction occurred in the whole examined potential range. Depressing effect of OVA increased gradually from reducing to slightly oxidizing potential, open circuit potential (OCP) of pyrite, mainly due to weak conformational changes in OVA molecules together with the hydrophobic interaction around OCP. The rate of depression reached its maxima at moderately oxidizing potentials, which was referred to electrostatic attraction. This level was almost kept at higher potentials owing to OVA adsorption as metal−chelates.
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