The addition of NaCl in the ammonium persulfate-APS (as an oxidant) leaching was investigated. AP... more The addition of NaCl in the ammonium persulfate-APS (as an oxidant) leaching was investigated. APS has some advantages compared with conventional oxidants and its standard redox potential (E°) is 2.0 V. Effect of six parameters such as NaCl concentration, APS concentration, temperature, time, liquid–solid ration (L/S), and stirring speed on the leaching behavior was studied. Results showed that metals extraction increased with increasing of NaCl concentration, APS concentration, leaching temperature (up to 333 K), and L/S ratio. During oxidative leaching of sulfide minerals, the occurrence of elemental sulfur layer on particle surface is known as primary problem that causes low metal extraction. According to the results, the passivation effect of sulfur layer and low dissolution problems can be eliminated in the presence of chloride ions. Copper and iron extraction yields were obtained as 75% and 80%, respectively under leaching conditions as follows: APS concentration 250 g/L; NaCl concentration 150 g/L; time 180 min; temperature 333 K; stirring speed 400 r/min; and L/S 250 mL/g.
Journal of Materials Science: Materials in Electronics, 2021
Numerous studies have revealed the properties of composites obtained by adding carbon nanotubes (... more Numerous studies have revealed the properties of composites obtained by adding carbon nanotubes (CNTs) into different polymer matrices. Although CNTs significantly improve the properties of the polymer matrix, problems are experienced in the production of composites due to CNTs. Therefore, only graphene nanoplates (GNPs) at the same rate along with CNTs were added into the polyester matrix which was used as a matrix in this study. In this way, the changes occurring in the properties of polyester were revealed. The mechanical properties of CNTs–GNPs reinforced polyester composite are lower than the composites reinforced only with CNTs. Besides, electrical conductivity of CNTs reinforced polyester composite was lower than CNT + GNP reinforced composite. Mechanical properties and electrical conductivity of both polyester–CNTs composite and polyester–CNT + GNP composite increased with increasing reinforcement ratio. In addition, the thermal properties were examined and glass transition temperature was determined as averagely 79 °C.
Physicochemical Problems of Mineral Processing, 2017
In this study, carbon composite pellets were exposed to a reduction test under low temperature an... more In this study, carbon composite pellets were exposed to a reduction test under low temperature and semi-fusion conditions in which iron was melted without a solid form of slag deteriorated. The purpose of the reduction experiments under the semi-fusion condition was to produce an iron nugget which had physical and chemical properties similar to blast furnace pig iron at lower temperatures. These nuggets were produced from pellets that were made from a mixture of iron oxide, coke, flux, and a binder. These nuggets heated in a furnace with a chamber temperature of 1330 C. The produced dried carbon composite pellets were melted and carbureted in a single-stage process. In this study, three distinct products were produced as a function of furnace residence time at fixed furnace temperature (1330 C). These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and iron nuggets produced at residence times 8-24, 32-40 min, and 48 min, respectively. The iron nugge...
This study has been conducted to determine whether iron nugget having similar features to pig iro... more This study has been conducted to determine whether iron nugget having similar features to pig iron that can be obtained after a period of nearly 8 hours under blast furnace conditions, could be obtained in shorter period. In our previous study, iron nugget was produced using carbon composite pellets obtained from magnetite ore at furnace temperature 1330 o C and furnace residence time 48 minutes. In this study the carbon composite pellets, produced using magnetite iron ore and coke through reduction at semi-fusion conditions, were used for production of iron nugget at furnace temperature 1410 o C and residence time 8 minutes. The reduction was carried out under semi-fusion conditions in order to produce an iron nugget having physical and chemical features that are similar to high furnace pig iron at lower temperature and furnace residence time. The iron nugget was produced from pellets composed of iron oxide, coke, flux, and binder. Its characteristics are: micro hardness of 343.4 H...
Bu çalışma, KBI (Samsun) Konverter flaş cüruf karışımlarının hidrojen peroksitli ortamda sülfürik... more Bu çalışma, KBI (Samsun) Konverter flaş cüruf karışımlarının hidrojen peroksitli ortamda sülfürik asitle liç işlemine tabi tutulması sonucu metallerin kazanımı ve liç kinetiğinin incelenmesi amacıyla yapılmıştır. 0.25 M H2SO4 ve 2.00 M H2O2 içeren karışımlarla 30–50C arasında değişen sıcaklıklarda süreye bağlı olarak yapılan deneylerle elde edilen sonuçlar, yüzey reaksiyonu kontrollü küçülen tanecik modeline ve difüzyon kontrollü küçülen çekirdek modeline uygulanmıştır. Sonuçlar difüzyon kontrollü modelle iyi bir uyum gösterdiğini ortaya koymuştur. Ayrıca Arhhenius eşitliğine göre, bakır liçinin aktivasyon enerjisi 31.63 kJ/mol Cu olarak hesaplanmıştır. Artan peroksit konsantrasyonuyla liç hızının az bir miktar arttığı, liç reaksiyonunun perokside göre mertebesinin 0.5-3.0 M konsantrasyon aralığında yaklaşık 1 olduğu belirlenmiştir. Cüruf karışımından bakırın liç kinetiğinin sülfürik asit konsantrasyonuna bağlılığını ortaya koymak üzere yapılan deneyler, 0.25-1.50 M H2SO4 konsantra...
The present communication reports the production of Cu81-Al13-Ni4-Ti2 shape memory alloy (SMA) by... more The present communication reports the production of Cu81-Al13-Ni4-Ti2 shape memory alloy (SMA) by an arcmelting method. A piece of this alloy is subjected to heat treatment at 930oC for 30 min and then shock-cooled in liquid nitrogen (-196oC), alcohol (0oC) and saline ice water (+6oC). Differential Scanning Calorimetry (DSC) is performed on samples with no heat treatment and on those subjected to three different heat treatments. It is found that the chosen heat treatments increase significantly the phase transformation temperatures of the shape memory alloy. Some changes in the microstructure of the alloy are also observed after the heat treatment. The grain boundaries become more pronounced, while the martensite plates increase in the samples which are shock-cooled in alcohol and saline ice water. The crystalline structures of the samples are investigated at room temperature. The XRD diffractograms reveal that bı phase (martensite phases) increases in the alloys subjected to heat t...
Aims: In this work, the effect of milling time on the mechanical alloying of the mixture containe... more Aims: In this work, the effect of milling time on the mechanical alloying of the mixture contained the magnetite concentrate and waste of biomass was investigated. Method: The ore consisting of hematite and magnetite was increased from 49.87% Fe to 67.29% Fe after the enrichment in the low field severe wet magnetic separator with a yield of 78.11%. Waste of biomass used as a carbon source was subjected to carbonization processes at 800 oC for 1440 min and the carbon content was determined as 94.68% and the sulphur content as 0.03%. Result: For the mechanical alloying process, a mixture of concentrated-biomass with a grain size of -45 μm was used such that the stoichiometric ratio of 2. After 5, 10, 15, 30 and 45 minutes of alloying, 90% of the mixture was reduced to 3.89 micron. In the SEM images, cube-like particles were seen along with spherical and narrowly spaced particles depending on the alloying times. After 45 minutes of alloying, the crystalline structure was found to be pa...
The addition of NaCl in the ammonium persulfate-APS (as an oxidant) leaching was investigated. AP... more The addition of NaCl in the ammonium persulfate-APS (as an oxidant) leaching was investigated. APS has some advantages compared with conventional oxidants and its standard redox potential (E°) is 2.0 V. Effect of six parameters such as NaCl concentration, APS concentration, temperature, time, liquid–solid ration (L/S), and stirring speed on the leaching behavior was studied. Results showed that metals extraction increased with increasing of NaCl concentration, APS concentration, leaching temperature (up to 333 K), and L/S ratio. During oxidative leaching of sulfide minerals, the occurrence of elemental sulfur layer on particle surface is known as primary problem that causes low metal extraction. According to the results, the passivation effect of sulfur layer and low dissolution problems can be eliminated in the presence of chloride ions. Copper and iron extraction yields were obtained as 75% and 80%, respectively under leaching conditions as follows: APS concentration 250 g/L; NaCl concentration 150 g/L; time 180 min; temperature 333 K; stirring speed 400 r/min; and L/S 250 mL/g.
Journal of Materials Science: Materials in Electronics, 2021
Numerous studies have revealed the properties of composites obtained by adding carbon nanotubes (... more Numerous studies have revealed the properties of composites obtained by adding carbon nanotubes (CNTs) into different polymer matrices. Although CNTs significantly improve the properties of the polymer matrix, problems are experienced in the production of composites due to CNTs. Therefore, only graphene nanoplates (GNPs) at the same rate along with CNTs were added into the polyester matrix which was used as a matrix in this study. In this way, the changes occurring in the properties of polyester were revealed. The mechanical properties of CNTs–GNPs reinforced polyester composite are lower than the composites reinforced only with CNTs. Besides, electrical conductivity of CNTs reinforced polyester composite was lower than CNT + GNP reinforced composite. Mechanical properties and electrical conductivity of both polyester–CNTs composite and polyester–CNT + GNP composite increased with increasing reinforcement ratio. In addition, the thermal properties were examined and glass transition temperature was determined as averagely 79 °C.
Physicochemical Problems of Mineral Processing, 2017
In this study, carbon composite pellets were exposed to a reduction test under low temperature an... more In this study, carbon composite pellets were exposed to a reduction test under low temperature and semi-fusion conditions in which iron was melted without a solid form of slag deteriorated. The purpose of the reduction experiments under the semi-fusion condition was to produce an iron nugget which had physical and chemical properties similar to blast furnace pig iron at lower temperatures. These nuggets were produced from pellets that were made from a mixture of iron oxide, coke, flux, and a binder. These nuggets heated in a furnace with a chamber temperature of 1330 C. The produced dried carbon composite pellets were melted and carbureted in a single-stage process. In this study, three distinct products were produced as a function of furnace residence time at fixed furnace temperature (1330 C). These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and iron nuggets produced at residence times 8-24, 32-40 min, and 48 min, respectively. The iron nugge...
This study has been conducted to determine whether iron nugget having similar features to pig iro... more This study has been conducted to determine whether iron nugget having similar features to pig iron that can be obtained after a period of nearly 8 hours under blast furnace conditions, could be obtained in shorter period. In our previous study, iron nugget was produced using carbon composite pellets obtained from magnetite ore at furnace temperature 1330 o C and furnace residence time 48 minutes. In this study the carbon composite pellets, produced using magnetite iron ore and coke through reduction at semi-fusion conditions, were used for production of iron nugget at furnace temperature 1410 o C and residence time 8 minutes. The reduction was carried out under semi-fusion conditions in order to produce an iron nugget having physical and chemical features that are similar to high furnace pig iron at lower temperature and furnace residence time. The iron nugget was produced from pellets composed of iron oxide, coke, flux, and binder. Its characteristics are: micro hardness of 343.4 H...
Bu çalışma, KBI (Samsun) Konverter flaş cüruf karışımlarının hidrojen peroksitli ortamda sülfürik... more Bu çalışma, KBI (Samsun) Konverter flaş cüruf karışımlarının hidrojen peroksitli ortamda sülfürik asitle liç işlemine tabi tutulması sonucu metallerin kazanımı ve liç kinetiğinin incelenmesi amacıyla yapılmıştır. 0.25 M H2SO4 ve 2.00 M H2O2 içeren karışımlarla 30–50C arasında değişen sıcaklıklarda süreye bağlı olarak yapılan deneylerle elde edilen sonuçlar, yüzey reaksiyonu kontrollü küçülen tanecik modeline ve difüzyon kontrollü küçülen çekirdek modeline uygulanmıştır. Sonuçlar difüzyon kontrollü modelle iyi bir uyum gösterdiğini ortaya koymuştur. Ayrıca Arhhenius eşitliğine göre, bakır liçinin aktivasyon enerjisi 31.63 kJ/mol Cu olarak hesaplanmıştır. Artan peroksit konsantrasyonuyla liç hızının az bir miktar arttığı, liç reaksiyonunun perokside göre mertebesinin 0.5-3.0 M konsantrasyon aralığında yaklaşık 1 olduğu belirlenmiştir. Cüruf karışımından bakırın liç kinetiğinin sülfürik asit konsantrasyonuna bağlılığını ortaya koymak üzere yapılan deneyler, 0.25-1.50 M H2SO4 konsantra...
The present communication reports the production of Cu81-Al13-Ni4-Ti2 shape memory alloy (SMA) by... more The present communication reports the production of Cu81-Al13-Ni4-Ti2 shape memory alloy (SMA) by an arcmelting method. A piece of this alloy is subjected to heat treatment at 930oC for 30 min and then shock-cooled in liquid nitrogen (-196oC), alcohol (0oC) and saline ice water (+6oC). Differential Scanning Calorimetry (DSC) is performed on samples with no heat treatment and on those subjected to three different heat treatments. It is found that the chosen heat treatments increase significantly the phase transformation temperatures of the shape memory alloy. Some changes in the microstructure of the alloy are also observed after the heat treatment. The grain boundaries become more pronounced, while the martensite plates increase in the samples which are shock-cooled in alcohol and saline ice water. The crystalline structures of the samples are investigated at room temperature. The XRD diffractograms reveal that bı phase (martensite phases) increases in the alloys subjected to heat t...
Aims: In this work, the effect of milling time on the mechanical alloying of the mixture containe... more Aims: In this work, the effect of milling time on the mechanical alloying of the mixture contained the magnetite concentrate and waste of biomass was investigated. Method: The ore consisting of hematite and magnetite was increased from 49.87% Fe to 67.29% Fe after the enrichment in the low field severe wet magnetic separator with a yield of 78.11%. Waste of biomass used as a carbon source was subjected to carbonization processes at 800 oC for 1440 min and the carbon content was determined as 94.68% and the sulphur content as 0.03%. Result: For the mechanical alloying process, a mixture of concentrated-biomass with a grain size of -45 μm was used such that the stoichiometric ratio of 2. After 5, 10, 15, 30 and 45 minutes of alloying, 90% of the mixture was reduced to 3.89 micron. In the SEM images, cube-like particles were seen along with spherical and narrowly spaced particles depending on the alloying times. After 45 minutes of alloying, the crystalline structure was found to be pa...
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