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This study compares the cementation performance of metallic iron, metallic aluminum, and metallic tin in terms of the reaction conditions and parameters in synthetic antimony chloride solutions. The effects on the antimony recovery (%) caused by the cementators\" types, stirring speed, reaction time, and temperatures were explored thoroughly. The cementation kinetics of antimony were also explored for each cementator. The activation energies were determined to be 10.99, 9.09, and 13.58 kJ mol(-1) for Al, Fe, and Sn, respectively. The results reveal that the reaction is diffusion controlled, and comparable results were obtained for each cementator. At 25 degrees C, 40 mg of iron powder was found to reduce all antimony ions (i.e., approx. 99% recovery), but even when 100 mg of Al and Sn cementators were used, the antimony recovery did not reach 100%. This result shows that iron is the best candidate to cement antimony out of the solution.

Antimonun geleneksel kullanım alanlarının yanında, son senelerde güneş enerjisi teknolojilerindeki gelişmeler antimon ve bileşiklerine duyulan ihtiyacının artması ve birincil kaynakların dünyada hızla tükenmesi ile artan kotalar ikincil kaynaklardan antimon geri kazanımının önemini arttırmıştır. Bu çalışma önerilen geri kazanım yönteminde, daha aktif metalin oksitlenerek iyonik haldeki antimonu indirgemesi ve redüksiyon işlemi sonucu metalik antimonun toz şeklinde üretilmesi amaçlanmaktadır. Cevher ve konsantre içeren oksit ve kükürt esaslı antimon, sırasıyla çeşitli asidik ve bazik çözeltiler ile işlenmiştir. Ancak geri kazanım oranı çok düşük olduğundan, ikincil bir kaynak olan asidik sentetik antimon çözeltilerinden antimonun metalik olarak çöktürülmesine etki eden parametreler detaylı olarak incelenmiştir. Deneysel çalışma şartlarına etki edebilecek sementasyon işlemi sırasında reaksiyon süresi, sıcaklık, başlangıç antimon konsantrasyonu, çinko tozu miktarı ve çözelti pH parametreleri incelenerek elde edilen antimon metalinin fiziksel ve kimyasal özellikleri karakterize edilmiştir. Deneysel çalışmalar sonucunda, 25 ml 1000 ppm Sb+3 sentetik çözeltisi 100 mg metalik çinko ilavesi ile 60 dev./dk. karıştırma hızı ile 5 dakika gibi çok kısa sürede %100’e varan geri kazanım verimine ulaşılmış ve % 99 saflıkta metalik antimon elde edilmiştir. Tek aşamalı sementasyonda 100 mg çinko ile % 100 geri kazanım sağlandığı durumda, iki aşamalı sementasyonda % 40 daha az çinko ilavesi ile aynı verime erişilmiştir.

Purpose The purpose of this study is to reveal the usability of waste paper sludge on the production of composite materials and the printability of their surfaces were investigated. Design/methodology/approach First, composite plates were produced by using dried and milled waste sludge together with polyester resin and epoxy. Screen printing using water, solvent and UV-based inks were carried out. Findings It was determined that UV and solvent-based inks in both resin groups were permanently attached to the surface of composite plates produced using paper mill waste sludge, while it was found that the adhesion was not achieved sufficiently in cardboard factory waste sludge. Originality/value The unique aspect of this study is obtained the composite plates from paper mill and cardboard mill waste sludge and improved the printability of them.

This study aims to explore the recovery of palladium (Pd(II)) ions using Lewatit TP 214 resins. Waste Pd(II) ions with ammonia complex procured from a precious metal plating were selected as the source solution. In the experimental studies, two stock solutions of 60 ppm Pd(II) with a pH value of 4.0 and 7.5 were prepared as initial solutions. The experiments were performed by altering four parameters: solution pH, time 15-180 min, temperature 25 degrees C-60 degrees C, and amount of resin 100-400 mg. It was proved that the recovery percentage increased with higher temperature and resin at lower pH values. The Pd(II) recovery percentage increased with a temperature rise, reaching 100% after 40 min at pH 4.0 and 60 degrees C. On the other hand, a bit lower efficiency (95%) was attained after 180 min at pH 7.5 and 60 degrees C. Using Lewatit TP 214, the computed activation energies for Pd(II) recovery are 17.73 and 15.62 kJ/mol at pH 4.0 and 7.5, respectively. Considering these activation energy values, a mixed mechanism dominated the recovery of Pd(II).

According to critical statistical studies, antimony is one of the rarest elements in the world, and global resources could be exhausted by 2050. In light of these observations, its extraction will be costly due to poor-quality ore, deep mining, remote locations, and high energy consumption. In the present study, an alkaline leaching process was carried out on stibnite concentrate to evaluate the effect of reaction parameters on the percentage of antimony extraction. The leaching efficiencies of different sulfur and hydroxide sources were studied and compared to one another to create a better understanding of the reaction process. Kinetic models were investigated to identify the reaction pathway and calculate the activation energy. The activation energy of the stibnite dissolution was assessed as 19.13 kJ/mol using a two-dimensional diffusion-reaction model. The value of activation energy indicates the quantity of energy necessary for a reaction to proceed. As expected, potassium hydroxide leaching was significantly more successful than was sodium hydroxide; however, in terms of economics, the use of sodium hydroxide was found to be more cost-efficient. Interestingly, this finding indicated that caustic leaching is still the most effective method for stibnite extraction.

Beingone the modern high quality industrial welding process especially for stainlesssteels and titanium alloys. TIG welding process has been has been researchedfor decades in order to define its parameters such as welding speed, currentand arc length to improve the weld penetration. Hence it is a popular techniquefor joining thin materials - the thickness of the work piece is in generalrestricted to less than 6 mm- inmanufacturing industries. In this study, AISI 321 and 316L stainless steelsheets of 4 mm of thickness were used as welding metals. Thus, AISI 321 weldingmetal couples, AISI 316L welding metal couples and AISI 321 and 316L weldingmetal couples were selected to ensure a combination of similar and dissimilarmetals. The filler metal rod was made of 316L SS. The specimens were cut indimensions of 150 x 30 x 4 mm as using an abrasive cutter, then the V weld buttjoint configuration with single groove of 37.5o ± 2.5o groove angle by a lathemachine. The welding current was 200 A and TIG welding process was performedmanually in single under argon shielding gas atmosphere. After TIG weldingprocess, the separate metallographic preparations, then microscopic andmacroscopic examinations of the specimens, also hardness measurements ofspecimens were made. The rest of them was shaped for tensile strengthmeasurement using Instron Universal Testing Machine. The hardness of thespecimens were observed being altered in the range of 145-151 HRV(average) andtheir tensile strength values in the scale of 345-400 MPa (average).

WOS: 000510612100009 This study investigates the effects of addition of Carbon nanotube (CNT) at different volume ratios (0.5- 5%) into Ti6Al4V matrix by mechanical alloying in terms of the density, microstructure, hardness and creep under dynamic load. As a result of the good bonding of carbon nanotubes powders with the main matrix, Ti-6Al-4V/CNT composites have experienced change both in microstructure and mechanical properties (such as hardness, density) and, correspondingly, qualitatively creep behaviour of Ti-6Al-4V matrix alloy has been improved compared to the lean one. The density of CNT reinforced Ti6Al4V composites sintered at 1300 degrees C for 3h decreases with increasing CNT content. The hardness tests indicated that the hardness of composites increased with CNT addition. In addition, although creep strain is decreased continually with CNT content until 5%, creep life increased with increasing CNT content until 4% of CNT but decreased above 4%. After sintering at 1300 degrees C under vacuum for 3 hours the density of the composite material reached to a level of 98.5 %, the microhardness to 538 HV and the creep behaviour was improved. The characterization of Ti6Al4V/CNT composites after mechanical alloying was carried out using scanning electron microscopy (SEM), energy dispersive x-rays spectroscopy (EDS) analysis and X-ray diffraction (XRD) methods. Although Ti-6Al-4V alloys are used as biomaterial, this study aimed at using MWCNTs containing Ti-6Al-4V composites at high temperature applications. Because MWCNTs reinforced Ti-6Al-4V composites are cheaper and have lower weight than the other materials used in this kind of applications. Scientific Research Project Program of Marmara UniversityMarmara University [FEN-K-070317-0107] This work was supported by the Scientific Research Project Program of Marmara University (FEN-K-070317-0107).

Hydroxylapatite, titania and Bioglass 45S5 are the components generally used for the production of bioactive biomaterials for years. In literature, although the binary composites with the permutation of three components exist, a ternary composite has not yet been tried. Primarily, Bioglass 45S5 was cast, its thermal analysis (Differential thermal analysis (DTA), dilatometric analysis), phase analysis (X-Ray Diffraction (XRD) ), microstructural characterization (Scanning Electron Microscopy (SEM) ) were performed. Then Bioglass 45S5 powder was ground to fine powder to make its particle size closer to the hydroxylapatite and the titania powders. The particle size of the powders were determined using the laser particle sizer. The DTAs of the 3 components, separately and mixed, were performed. They were then mixed, and ball-milled during 24 hours for a better homogenization. Following drying for 24 hours, pellets of 1 inch diameter were obtained using unaxial manuel press and sintered at 1000, 1100, 1200 °C. Mechanical testing (compression and microhardness), porosity measurement (The Archimèdes Method), phase determination (XRD) and microstructural characterization (SEM) of the composites were then performed. As a conclusion, when sintering temperature was increased, the porosity in the structure was decreased. Between 1100 °C and 1200 °C, a phase transformation occurred. The results of microhardness ( 24.6, 38.99, 316.2 HV (500gf for 15 sec) for the composites sintered at 1000, 1100, 1200 °C, respectively) and subsequent compression tests (93.023±10.5, 298.14±78.074, 371.9684±38.36 MPa, respectively) approved the possible phase transformation between 1100 °C and 1200 °C along with the XRD results.

Alumina is a biomaterial of choice for more than 20 years due to its high hardness accompanied by low friction, wear and inertness to in vivo environment. It has been reported that titanium oxidized to the rutile phase is bioactive. This is a property discovered for certain ceramics such as Bioglass and sintered hydroxylapatite (HA). But the combination of alumina and titania forming tialite (Aluminium titanate-50 mol % Al2O3 and 50 mol % TiO2) is a new challenge. In this work we made firstly the beneficiation of the Seydisehir alumina by leaching it in the acidic solution “the Aqua Regia” followed by preparation of batches containing 2,5 wt %, 3,5 wt % and 4,5 wt % of MgO as the sintering aid, 1 wt % of SiO2 and the balance; the alumina and titania powder mixture (1:1 mole). After sintering these batches at 1600°C for about 12 h, their mechanical properties (the compression and hardness testings) and phase ratios (the XRD analysis) were analyzed and compared with the control group containing the laboratory scale alumina instead of the Seydisehir alumina. Following the characterization (the SEM and the EDS analysis) of the substrate material, the comparison of two different materials was carried out.

and Fracture Toughness of BaTiO3 B. Ertu§, B.N. Cetiner, G. Sadullaho§lu, H. Gokce, Z.E. Erkmen and M.L. Oveco§lu Orion Company Industry and Trade Ltd., Organized Industrial Zone, Metal 3 Sanayi Sitesi 5. Blok No:2, Ikitelli, Istanbul, Turkey Marmara University, Metallurgical and Materials Eng., 34722 Goztepe, Istanbul, Turkey Istanbul Technical University, Metallurgical and Materials Eng, 34469 Maslak, Istanbul, Turkey