Mixing Of Raw Materials Research Articles

Isolantes térmicos produzidos a partir de resíduos sólidos industriais

Resumo Composições contendo dois diferentes tipos de resíduos, vidro de garrafas transparentes, VGT (50-70%), e lodo de estação de tratamento de efluentes, ETE (30-50%), e formador de poros, CaCO3 (2-10%), foram preparadas para a produção de isolantes térmicos para fins estruturais. As matérias-primas das composições formuladas foram, em uma etapa posterior, misturadas, compactadas uniaxialmente a 40 MPa e, após secagem (110 °C/2 h), queimadas entre 750 e 1000 °C com patamares de 15 a 60 min. As matérias-primas e os materiais obtidos foram caracterizados do ponto de vista de suas propriedades químicas, físicas e microestruturais. Os resultados obtidos mostraram que é possível produzir isolantes térmicos, a partir de composições otimizadas contendo 70% de VGT, 30% de lodo de ETE e 5% de CaCO3, queimados entre 750 e 1000 °C/60 min, os quais apresentaram porosidades entre 3 e 62% com condutividades térmicas entre 1,25 e 0,5 W/m.K e com resistência à compressão entre 8,7 e 5,4 MPa. Os materiais obtidos são fortes candidatos em aplicações estruturais tais como painéis para isolamento térmico, os quais requerem uma combinação adequada de condutividade térmica, porosidade e resistência mecânica.

Development of Carbon-based Composite Materials for Energy Storage

The following work aims the preparation and characterization of electrodes for supercapacitors employing different carbon materials and their integration functional prototypes. Preparation of electrodes was conducted in two steps; I) formulation and mixing of raw materials and II) coating of the aluminum foil that supports the electrode with the mixture of materials. Different compositions and formulations were carried out to prepare the electrodes. Electrodes were composed by a matrix polymer of PVDF (Polyvinylidene Fluoride) and several carbon material additives (activated carbon, graphite, carbon black, carbon nanotubes and graphene) that ensured a high specific capacity and low electrical resistance. Finally, the build-up of “single-cell” prototypes employing the electrodes was carried out to validate their performance. Galvanostatic charging/discharging cycles, cyclic voltammetry and impedance spectroscopy to characterize the electrodes and prototypes were performed. From these experiments important parameters of a supercapacitor were estimated; equivalent serie resistance (ESR) and specific capacitance (F/g). Results of characterization have shown high capacities and good kinetics in the electrodes developed.

Sulfuric acid hydrolysis of various lignocellulosic materials and its mixture in ethanol production

Lignocellulosic materials sustainability in ethanol production could be supported by the use of mixed raw materials. Therefore the effect of mixed raw materials to hydrolysis kinetics needs to be studied. For this purpose each raw material was hydrolyzed and the mixed raw materials were also hydrolyzed. As a result, a comparison of the kinetics models of dilute sulfuric acid hydrolysis between various lignocellulosic materials (leaf, twig, corn cob, sawdust) and its mixture was obtained. It was observed that a pseudo-homogeneous model can quantitatively describe individual materials as well as mixed materials with different levels of accuracy. Besides the kinetics model, the influence of various lignocellulosic materials on sugar yield was also investigated. The results showed that the lignin content of the raw material influenced the sugar yield of the hydrolysis. Moreover the mixed lignocellulosic materials did not proportionally provide a yield based on its composition. Some hydrolyzates were fermented to verify whether the sugars formed could be converted into ethanol using Saccharomyces cerevisiae. The fermentation results showed that high sugar concentrations of hydrolyzates did not produce high ethanol yields. The various sugar types and the chemical substance of the sugar degradation affected the ethanol yield from sugars.

Optimized synthesis of LiFePO4 composites via rheological phase assisted method from FePO4 with acetic acid as dispersant

LiFePO4 composites were synthesized by aqueous ball milling and carbon thermal reduction from FePO4·2H2O through a rheological phase using acetic acid as dispersant. The rheological phase assisted method using acetic acid as dispersant improved the homogeneity of mixing raw materials. Li deficiency and solid-solution Mg dopant in the lattice of LiFePO4 was created through controlled off-stoichiometry Li/Fe ratio. Li deficiency, solid-solution Mg doping and uniform carbon layer decreased electron transfer and Li-ion diffusion resistance. The optimal LiFePO4 composite exhibited a high rate capability with 153mA·h·g−1 at 1C and 111mA·h·g−1 at 20C as well as a stable capacity retention with 99% for 100 cycles at 2C and 98% for 200 cycles at 5C. The rheological phase assisted method from FePO4 with acetic acid as dispersant is a promising route for production of high quality LiFePO4 materials at a reasonable cost.

One-step solid-state synthesis of Li4Ti5O12/C with low in situ carbon content and high rate cycling performance

Spinel Li4Ti5O12/C composites were obtained from C3H5O3Li and TiO2 via one-step solid-state reaction without adding extra carbon sources. This facile synthesis method can reduce production steps, contribute to uniform mixing of raw materials, and get homogenous particles. As-prepared Li4Ti5O12/C composites with low in situ carbon content of only 1.81 wt% show significant improvement in discharge capacity and high rate cycling performance comparable to Li4Ti5O12/C in previous studies, showing that low in situ carbon content in the as-prepared Li4Ti5O12/C composites perfectly balances discharge capacity and high rate cycling performance. At 1 C and 10 C, the initial discharge capacity is 168.0 and 140.0 mAh g−1 with capacity retention of 94.4 and 90.2 % after 200 cycles, respectively. Even at 20 C, the discharge capacity is 133.3 mAh g−1 at 1st cycle and 109.8 mAh g−1 at 50th cycle. It demonstrated promising potential as an anode material in lithium-ion batteries with excellent discharge capacity and high rate cycling performance.

The addition of transglutaminase improves the physical quality of extruded fish feed.

The possibility of improving the physical quality of extruded fish feed using transglutaminase (TGase) treatment at different stages of the production process was investigated. The addition of TGase to the raw material mix and processing under high and medium moisture conditions significantly increased (p>0.05) the durability, hardness and elasticity of fish feed pellets. However, the water stability of feeds was only improved when the TGase was applied in the vacuum coater; when it was mixed with the dry raw materials, the water stability of the product decreased. By further optimization of the enzyme dose when added to the vacuum coater, an increase in pellet durability was observed at enzyme dosages between 2.5 and 5 gkg(-1). Application of TGase in the coating step allowed an 87.5% decrease in the dose of enzyme in feed produced under high moisture conditions. TGase treatment improves the physical quality of extruded fish feed, and the importance of optimization of enzyme dosage and processing conditions was demonstrated.

EFFECT OF PROPORTION OF HOME AND EXTERNAL SCRAP ON THE MECHANICAL PROPERTIES OF RECYCLED PVC: A COMPARATIVE STUDY

Raw material powder mixtures have been prepared with PVC resin, unplasticized polyvinylchloride (uPVC) scrap and additives. A twin screw extruder has been used to make pipe for sample preparation from the mixture. Domestic and external uPVC scrap were formulated and blended with PVC resin to form melt compound. Domestic samples designated as DS-10, DS-20, DS-30, DS-40, DS-50 and DS-100 have been prepared by blending 10, 20, 30, 40, and 50 phr and 100% uPVC domestic scrap with PVC resin and various additives, followed by extrusion, flattening and machining. Following a similar procedure, external samples such as ES-10, ES-20, ES-30, ES-40, ES-50 and ES-100 have been prepared using external uPVC scrap. The effects of the proportions of uPVC scrap in the raw material mix on the mechanical properties such as break stress (BS), % elongation at break, flexural yield strength [1], impact strength (IS) and Shore hardness were investigated. The maximum decrease in break stress is 11.40% for 20 phr domestic scrap, while in samples containing external scrap this decrease is 15.71% for 40 phr scrap. The minimum and maximum reduction in IS values of DS are recorded 1.0% for DS-10 and 27.4% for DS-40, respectively, whereas the minimum and maximum decrease in IS values of ES recorded are 9.6% for ES-10 and 39.2% for ES50, respectively. The minimum and maximum increase in hardness values of DS are recorded as 0.07% for DS-40 and 2.8% for DS-10, respectively, whereas the minimum and maximum reduction in hardness values of ES are recorded as 1.2% for ES-50 and 2.2% for ES-20, respectively. The mechanical properties of samples were found to deteriorate with increasing quantity of scrap in the raw material mix, the effects of external scrap being more prominent.

Development of new WC–Ni hardmetals for use in high pressure experiments

Ultrafine-grained (0.2–0.3 µm) WC–Ni hardmetals with a low Ni content (3–5 wt%) were developed using new production techniques based on adding an appropriate amount of VC and Cr3C2, combined with the strong mixing of raw materials. Their uniaxial compressibility was subsequently compared with that of existing WC–Ni and WC–Co hardmetals to assess their suitability for use as anvils in various high pressure experiments, particularly those associated with neutron or magnetic studies. The ultimate compressive strength of the newly developed hardmetals was over 7.7 GPa, which was higher by 1.2 GPa than that of the existing WC–Ni hardmetal ‘MF10’. When these hardmetals were used as anvils, a pressure of approximately 16 GPa was generated using a Paris-Edinburgh-type apparatus with φ8 mm culet, thereby proving that they can allow the physical properties of various materials to be measured at higher pressures than is possible with existing hardmetals.

A facile synthesis and characterization of LiFePO4/C using simple binary reactants with oxalic acid by polyol technique and other high temperature methods

An attempt has been made to synthesize the carbon coated Fe-based phospho-olivine nano-crystalline cathode materials using simple binary sources via polyol method. Also, a curious attempt has been made to compare the material with the high temperature methods, viz., hydrothermal and solid state method with the same binary sources as raw materials and oxalic acid as a carbon source. The thermal behaviour of the mixed raw materials of LiFePO4 and thermal stability of the final prepared materials were characterized by TGA. The prepared materials were confirmed as orthorhombic olivine structure with Pnma space group. LiFePO4/C material prepared by Polyol method exhibits an initial reverse capacity of 150 mAh g−1 at 0.1 C rate under room temperature. Also, stable capacity of 143 mAh g−1 has been observed over 50 cycles at 0.1 C rate at room temperature among the other methods studied. It may be due to the coverage of tiny particles by carbon and it leads to provide better electronic conductivity and thereby provides good electrochemical performances.

Investigation of the compressive strength, time lags and decrement factors of AAC-lightweight concrete containing sugar sediment waste

Sugar sediment waste was incorporated into the raw material mix for the production of Autoclaved Aerated Concrete, and was demonstrated by extensive testing to provide greater compressive strength than conventional materials, and an extended time lag. In addition, the use of this otherwise waste material was demonstrated to be highly beneficial both economically and environmentally. Sugar sediment is a waste product of the sugar refining industry in Thailand, and is available in huge quantities.The optimum composition obtained had sugar sediment content of 30% by weight replacement of sand and 7.5% by weight of lime. The resultant product showed a maximum compressive strength of around 6.1N/mm2 and the highest proportion of tobermorite phase of 28.9%. The higher strength can be confirmed by a higher crystalline tobermorite phase. The surface of the Autoclaved Aerated Concrete is a finer needle-like crystalline morphology. The Autoclaved Aerated Concrete consisting of the optimum sugar sediment content also extended the time for the heat wave to propagate from the outer wall to the inner wall. This study also considered the environmental, economic and health impacts of removing a substantial quantity of the industrial waste product from landfill sites.

Establishment and assessment of a novel bioethanol and efficient biogas coupling fermentation system integrated with the pretreatment of a cellulolytic microbial consortium

Abstract A novel bioethanol and biogas coupling fermentation system integrated with the pretreatment of a cellulolytic microbial consortium was proposed to treat cassava distillage. In the present study, 8 batches of ethanol fermentation integrated with 7 batches of biogas fermentation were successively proceeded. The recycled water after two-stage of anaerobic digestion was reused for raw material mixing in the later 7 batches of ethanol fermentation, whereas only tap water was used in the first batch. It was found the ethanol yield, starch utilization ratio, fermentation time can be kept steady at about 12.6%(v/v), 90% and 48 h respectively during the recycling process, which were very close to those of the conventional process using tap water. The organic substrates, volatile fatty acids, total and ammonia nitrogen reached steady states after 2-5 batches of recycling, while the total ion and alkalinity revealed a little decrease tendency with the increment of the recycling batches. Further, the total methane yield and methane producing velocity of each recycling batch in the proposed coupling system could reach 180–206 L and 40–45 L CH4 L−1 d−1 (litres of methane generate per litre of reactor volume per day) respectively, which was 16.1–32.9% and 25–40.6% higher than those of the original one. In addition, the total mass yield obtained by the combination in the proposed coupling system was 317 g ethanol plus 68.7 g methane/kg cassava, and 8.3% higher energy was generated compared with the original system. In conclusion, the insertion of a biological pretreatment step into the proposed coupling system revealed obvious superiorities and applicable potential.

Specific Study of Airport Pavement Asphalt Mixture

In order to reduce the influence of mixing building material quality variability of asphalt mixture. On the basis of Kunming Changshui International Airport West runway mixing by disk data, The proportional difference standard deviation as the index, Study on the quality stability of the mixture of different types of mixing the raw material consumption variability, hybrid variant gradation and the mixing process. The analysis results show that Factors of mixing type, control accuracy and operating method of great quality variability of asphalt mixture; Different variability of various mixing raw materials; Mixture gradation variability index in 9.5mm, 4.75mm and 2.36mm sieve is greater, And the maximum at 4.75mm; Mixing plant start and end of the mixture quality variability than mixing intermediate stage. Finally, aiming at the mixing plant proposed a series of measures to reduce the mixture quality variability.

Effects of mixing and covering with mature compost on gaseous emissions during composting

This study investigated effects of mature compost on gaseous emissions during composting using pig manure amended with corn stalks. Apart from a control treatment, three treatments were conducted with the addition of 5% (wet weight of raw materials) of mature compost: (a) mixing raw materials with mature compost at the beginning of composting; (b) covering raw materials with mature compost throughout the experimental period; and (c) covering raw materials with mature compost at the start of composting, but incorporating it into composting pile on day 6 of composting. Mature compost used for the last treatment was inoculated with 2% (wet weight) of raw materials of strain M5 (a methanotrophic bacterium) solution. During 30-d of composting, three treatments with the addition of mature compost could reduce CH4 emission by 53–64% and N2O emission by 43–71%. However, covering with mature compost throughout the experimental period increased cumulative NH3 emission by 61%, although it could reduce 34% NH3 emission in the first 3d. Inoculating strain M5 in mature compost covered on the top of composting pile within first 6d enhanced CH4 oxidation, but simultaneously increased N2O emission. In addition, mixing with mature compost could improve compost maturity. Given the operational convenience in practice, covering with mature compost and then incorporating it into composting pile is a suitable approach to mitigate gaseous emissions during composting.

Determination of the protective atmosphere during the Pb–Li alloy remelting

Nuclear fusion technology has been planned as a future massive source of energy. One of the most critical parts of its design is regenerating blanket modules. Among the different materials currently considered for this purpose, we have studied the Pb–Li eutectic alloy. For the production of the eutectic alloy, it is vital to ensure efficient mixing of raw materials, which is hampered by large difference in density of the two components and the high reactivity of Li versus O2. This work addressed this issue by presenting a series of tests were made with eutectic ingots in order to determine the composition of protective atmospheres and crucible material. Alloys manufactured were characterized by microscopy and ICP-MS. The results demonstrate that the best crucible material when making mergers is the SiC, due to the low reactivity presented with Pb–Li. Regarding protective atmosphere, Ar BIP (Built-In Purifier) showed the best protection and can be used in a wide range of temperatures and the eutectic salts improve this protection.

Design and Fabrication of Horizontal Screw Type Mixer for Livestock Feed Meal

Small-scale livestock raisers are in dire need of a highly nutritious poultry feed to increase production output. And efficient mixing is the next key to good feed production. The mixing time for a batch of ingredients varies according to the design of the mixer, thus designing a fabricated horizontal screw type mixer was necessitate. The horizontal screw type mixer for livestock feed meal was fabricated using metal working concepts. The main components are the housing, bucket, rotor assembly and gear box. Experimental design was made to obtain the machine performance like pulley ratio, number of paddles/ blades, and the driving gear ratio. The machine used four (4) inches diameter pulley at the gear box and seven (7) inches diameter pulley at the gear box and seven (inches) diameter pulley at the motor connecting with a V-belt, eight paddles were installed at the rotor shafting for good mixing capability. The driving gear used 18 teeth at the upper sprocket and 36 teeth at the lower sprocket to obtain past and efficient mixing of raw materials in the production of feeds. It is powered by one half horse power electric motor. The machine could produce in an average of 15 kilograms in two (3.66) minutes.

Silicomanganese production utilising local manganese ores and manganese rich slag

Silicomanganese (SiMn) is widely used in Egypt as a complex reducer and alloying addition in the production of various grades of steel due to its economic and metallurgical advantages. This work investigated the possibility of using local Egyptian manganese ores mixed with ferromanganese slag to produce SiMn alloy in a submerged arc furnace at a relatively low temperature. This paper discusses the optimal choice of raw materials mix and optimum conditions controlling the production process, such as smelting time, basicity, coke ratio, Mn/Fe and Mn/Si ratios of the blend to obtain standard SiMn. At the optimum conditions, a standard SiMn alloy containing 65·9–69·0%Mn, 15·6–17·6%Si, 1·8–2·35%C, 0·1–0·2%P and 0·015–0·025%S has been successfully produced.

Development of a Raw Material Requirement Balancing Model for a Production Process

Attainment of accuracy in raw materials mix for production processes has been the major problem in many production organizations in developing countries. Effects of unequal proportions of material required for a production process are not fully considered in the past studies. This study modeled the raw material requirements in a production process using proportionality based mixed linear programming approach. The objective was to find optimal mix of raw materials for the production of a unit tonnage of a product. The performance of the model was tested by comparing it with alternatively formulated model based on conventional material mix. This model was tested using a cement production system from which blasted limestone, crushed limestone; raw meal, gypsum, red alluvium, clinker and coal were used as raw materials. The conventional method of mixing materials led to 50 % surplus and shortage of materials in the process as compared with the new scheme. The model would be a good tool for accurate prediction of quantity of the raw material required in the production process.Nomenclature, the proportion of material used per ton of the processed product, the quantity of material in processed product (ton), the material proportional per ton of the product, andthe total quantity of materials needed per ton of the product,..., the counter for material type,..., the counter for material proportionality variant

Process parameter optimization for synthesis of high-silica liquid-glass composites for construction

The technological factors intensifying hardening and structure-formation in the system quartz-sand – liquidglass are studied. The temperature-moisture conditions for the solidification of compositions, filler dispersity, modifier form and amount and quantitative ratio of the components of the raw materials mix are optimized. High-silica liquid-glass construction-grade composites with high mechanical strength and water-resistance are worked out.

Synthesis and properties of inorganic pigments based on pyrochlore compounds with different lanthanides

For the last few decades the attention to the ecological problems, which primarily concerns the pigmentary field of research, constantly increased. So we have prepared new ecological pure thermally stable inorganic pigments with yellow, orange and red colours based on pyrochlore structure. The series of pigments have been prepared by two different methods (namely by solid state reaction and suspension mixing of raw materials). The goal was to develop conditions for the synthesis of this type of pigments and to determine the influence of the lanthanides (Ln = Dy, Ho, Er, Tm, Yb and Lu) and preparation methods on the colouring effect and properties of oxides based on Ln–Zr–V. All prepared pigments were applied into organic matrix in mass tone. The compounds were evaluated from the standpoint of their structure, thermal stability, colour properties and particle size distribution. Obtained results indicated that these pigments can provide rich yellow and orange hues.

Controlling microstructure in cement based mortars by adjusting the particle size distribution of the raw materials

Dry mortars consisting of Portland BL I 52.5 R cement (14%), dolomite and CaCO3 sands (85,8%) and organic additives (0.2%) were studied. Three types of dolomite sands with mean grain size >1.0mm, 0.0–1.0mm and 0.0–0.5mm range were used. The mortars were prepared from variable amounts of each raw material (dolomite and CaCO3 sands) and in variable W/C ratios. The particle size distribution curves for the overall mixed raw materials were used for anticipating the microstructure and mechanical properties of cement based mortars.