Selection of Binder Materials for the Production of Extruded Briquettes

Carbon nanofibers and PVA fiber hybrid concrete: Abrasion and impact resistance

Granules were prepared using three different binders, pregelatinized starch (PGS), gelatin (GEL), and polyvinylpyrrolidone (K30) by a fluidized bed method. As a quantitative measurement of mechanical strength or abrasion resistance, granules were subjected to a friability test for certain periods of time, and friability indexes (FI) as a function of time were calculated. The data obtained were analyzed by applying standard mathematical models. According to the derived parameters of the logistic and Weibull models, which fit best to the data, mechanical strength of granules made with K30 was observed to be lower than that of the granules of PGS and GEL which have similar values of model parameters. Flow properties, consolidation, and compressibility behaviors of unfriabled (UFR) and friabled (FR) granules, which were selected based upon their Weibull time parameter, were investigated as comparative. The flow rate of granules decreased due to diminishing particle size depending on binder type and friability, but the values of angle of repose were within the acceptable limits. Regarding consolidation behavior, the change of relative density vs. the number of taps, i.e., packing rate for FR granules of GEL was slower than that of its UFR form, whereas FR granules of PGS and K30 showed faster change in relative density compared to their UFR forms. According to the parameters obtained from the Heckel equation, PGS and K30 were found to produce softer, more plastic and readily deformable granules than GEL, and the compressibility of their FR forms was not influenced negatively.

The purpose of the work is to analyze existing preconditions, driving forces, and barriers for the widespread introduction of the production and use of fuel briquettes from biomass in Ukraine. The task of the work is to determine the advantages and prospects of the process, first of all, for domestic consumers, as well as to develop recommendations for creating a positive environment for the development of this segment of bioenergy in Ukraine. In this part of the paper, the main types of briquettes from biomass and their fuel characteristics are considered. It is shown that density is the main factor determining the mechanical strength and water resistance of the briquettes. Usually, it is 0.8...1.2 t/m3 with a water content of pressed biomass of 8...14%. The calorific value of the briquettes depends on the type of the initial feedstock and on the moisture content. The typical range ​​of the lower calorific value of briquettes from biomass is 16...17 MJ/kg. The legislative aspects of the production of briquettes from biomass, issues of standardization and certification of the products are analyzed. The legislative basis for the production of fuel briquettes from biomass can be found, mainly, in the Laws of Ukraine “On Alternative Fuels” and “On Licensing Types of Economic Activities”. It was determined that one of the constraining factors for the development of this segment of bioenergy is the lack of a sufficient number of relevant state standards and the reliable certification system. Solutions to these issues will help to improve the quality of briquettes from biomass and, accordingly, improve their fuel characteristics. It is also recommended that experts should develop standard feasibility studies and business plans for the production of fuel briquettes from biomass to demonstrate the economic attractiveness of this type of activity and its practical implementation. Particular emphasis should be put on the use of biomass of agricultural origin as feedstock for the production of briquettes. It is expected that the introduction of the biofuel electronic trading systems in Ukraine, which is already under development, will have a positive impact on the development of production and consumption of briquettes from biomass.

The biofuel industry seeks materials that can reduce maintenance costs and enhance product quality. Low alloy ferritic stainless steel, specifically P410D with 11%wt Cr, 0.01%wt C, and 0.3%wt Ni, shows promise due to its superior wear-corrosion resistance compared to structural carbon steel. Maintaining corrosion resistance while improving mechanical strength is crucial for this sector. This study investigates the impact of austenitising temperature on the abrasive wear resistance of P410D ferritic stainless steel + nickel. Austenitising temperatures from 850°C to 1050°C were tested, followed by air quenching. Additionally, the annealed and 1050°C austenitised samples were field-tested in a biofuel industrial setting to observe real-world wear micromechanisms. Alongside laboratory evaluations using a fixed-ball micro-scale abrasive wear test, were conducted. SEM images revealed grooving as the predominant wear micromechanism due to abrasive particle sliding. Samples austenitised below 950°C exhibited a biphasic microstructure of martensite and ferrite, with properties dependent on martensite fraction. Temperatures above 950°C resulted in a fully martensitic microstructure. The heat treatment increased hardness by 78%, yield strength by 117%, and decreased ductility by 169%. The sample austenitised at 1050°C showed the lowest wear rate in both field and laboratory tests, with a 77% increase in abrasion resistance. Laboratory tests confirmed a positive correlation between wear resistance and austenitising temperature. Optimizing austenitising temperature thus enhances the abrasive wear resistance of P410D ferritic stainless steel, making it a viable material for the biofuel industry.

Turning the food waste into a fuel source such as charcoal briquette was one of the alternatives in managing the food wastes disposal. In this present work, food waste was converted into charcoal by microwave irradiation technique. Application of binders such as potato starch and carboxymethyl cellulose (CMC) at ratios of 5%,10% and 15% for briquetting purpose were investigated in terms of its chemical and physical characteristics. Result showed that the briquette formed using the starch as the binder performed better in combustion quality than that of carboxymethylcellulose (CMC). A good quality of charcoal briquette has capability to withstand impact during packaging, handling, and transportation. Standard physical characteristic that was tested for briquette includes moisture content, compressive strength, and impact resistance. Calorific value of briquette was studied to analyse energy content in the briquette. The study showed that food waste charcoal has calorific value comparable to that of the commercial charcoal. However, the addition of binders showed some reduction in the energy content, with more reduction when CMC is added. In terms of combustion characteristic, the addition of binders does not alter the combustion profile in comparison to the raw food waste charcoal’s profile. The ignition and burnout temperatures of the food waste charcoal briquette showed a better performance with and without binders as compared to the commercial charcoal. In terms of physical characteristics, CMC has showed as an excellent binder with highest shatter index value. Overall, in terms of chemical properties, addition of 10% starch showed a better performance, while addition of 10% CMC showed a better performance in terms of physical characteristics. This finding is beneficial for briquette industry in the development of green product using biomass, but further research is essential before production of briquette take place.

In the construction industry, the lack of supply and demand for high-quality natural aggregates is a problem. In the case of South Korea, according to data from the Ministry of Environment, it is predicted that the depletion of aggregate resources will occur in 20 years, considering the amount of aggregate used in construction every year and the amount of natural aggregate. Therefore, it is necessary to develop recycled aggregates that can replace natural aggregates for construction. The purpose of this study is to evaluate the applicability of recyclable air-cooled slag (ACS) aggregates as a substitute material for natural aggregates applied to rural-road pavement concrete. That is, the applicability of rural-road pavement concrete is evaluated by evaluating the strength and durability of rural-road pavement concrete to which an ACS aggregate is applied. Durability was assessed in terms of the chloride ion diffusion, repeated wetting-drying, abrasion resistance, impact resistance, and repeated freezing-thawing tests. The test result showed that the diffusion coefficient of the mixture to which the ACS aggregate was applied was slightly larger. In addition, the diffusion coefficient was slightly larger in the case of applying the air-cooled slag coarse aggregate (GG) than in the case of applying the air-cooled slag fine aggregate (GS). The results of abrasion and impact resistance tests of ACS-aggregate-incorporated rural-road concrete indicated that abrasion and impact resistance decreased as the aggregate content increased. The ACS retained some of the properties of the blast furnace slag. Thus, in repetitive wetting-drying tests, which can cause changes in chemical properties, the ACS aggregate increased the concrete’s long-term residual strength. In addition, the results showed that the relative dynamic elastic modulus targeting repeated freezing-thawing resistance satisfied the 80% target. The freeze-thaw resistance improved as the ACS aggregate content increased. In conclusion, the results of this study showed that the durability of rural-road pavement concrete can be improved experimentally by applying both GG and GS at the same time. Therefore, it is shown that ACS aggregates can be applied to rural-road pavement concrete as a substitute for natural aggregates.

This study examined the mechanical and durability properties of CaO-activated ground-granulated blast-furnace slag (GGBFS) concretes made with three different additives (CaCl2, Ca(HCOO)2, and Ca(NO3)2) and compared their properties to the concrete made with 100% Ordinary Portland Cement (OPC). All concrete mixtures satisfied targeted air content and slump ranges but exhibited significantly different mechanical and durability properties. The CaO-activated GGBFS concretes showed different strength levels, depending on the type of additive. The added CaCl2 was the most effective, but Ca(NO3)2 was the least effective at increasing mechanical strength in the CaO-activated GGBFS system. The OPC concrete showed the most excellent freezing–thawing resistance in the durability test, but only the CaO-activated GGBFS concrete with CaCl2 exhibited relatively similar resistance. In addition, the chemical resistance was significantly dependent on the type of acid solution and the type of binder. The OPC concrete had the best resistance in the HCl solution, while all CaO-activated GGBFS concretes had relatively low resistances. However, in the H2SO4 solution, all CaO-activated GGBFS concretes had better resistance than the OPC concrete. All concrete with sulfate ions had ettringite before immersion. However, when they were immersed in HCl solution, ettringite tended to decrease, and gypsum was generated. Meanwhile, the CaO-activated GGBFS concrete with CaCl2 did not change the type of reaction product, possibly due to the absence of ettringite and Ca(OH)2. When immersed in an H2SO4 solution, ettringite decreased, and gypsum increased in all concrete. In addition, the CaO-activated concrete with CaCl2 had a considerable amount of gypsum; it seemed that the dissolved C-S-H and calcite, due to the low pH, likely produced Ca2+ ions, and gypsum formed from the reaction between Ca2+ and H2SO4.

A polycrystalline diamond compact (PDC) bit has advantages, such as a fast drilling rate and long drilling footage, but its abrasive resistance is low. Although an impregnated diamond bit has a high abrasive resistance, the corresponding rate of penetration (ROP) is low. In view of the difficulties of rock breaking in hard rocks and the characteristics of each cutter type, it is necessary to design a new hybrid drill bit with multiple cutting functions. Through laboratory experimentation and analysis, this study investigated a conical PDC cutter with a strong penetration capacity, abrasive resistance, and impact resistance, and developed a new diamond-impregnated block embedded with natural diamonds, with consideration of its matrix formulation and diamond grades, sizes, and concentrations. Moreover, this research optimized the crown shape, blades, cutters’ position, and number with a reinforced hydraulic structure. The combination of three cutters with different structures enables the drill bit to adapt to drilling in hard rocks and greatly improves the rock-breaking efficiency and service life of the drill bit. The drilling test was conducted of the well Jingu 1-1HF in the Jinshan gas field and drill bit demonstrated excellent performance.

In order to obtain a proper powder injection molding the rheological behavior of feedstocks should be known. To determine the binder effect on the rheological behavior of 316L stainless steel powders feedstock two different feedstock were prepared. In the current experiments water atomized 316L stainless steel powders (-20 µm) were used. Two types of binders, one of which is mainly paraffin wax can be dissolved in heptane and the other Polietilenglikol (PEG) based and can be dissolved in water, were used. Polypropylene was used as binder and steric acid was used as lubricant for both binder systems as skeleton binder. Dry binder system were mixed for 30 min in a three dimensional Turbola. Capillary rheometer was used to characterize the rheological properties of feed stocks at 150-200 °C and a pressures of 0.165-2.069 MPa. Powder loading capacity of PEG and PW based feed stocks were found to be %55 and %61 respectively. The lowest viscosity of PEG and PW based feed stocks were found to be 304.707 Pa.s and 48.857 Pa.s respectively. Keywords: PIM, Binder, Rheological properties

Composites of different composition and structure have been obtained on the basis of crushed porous stems of Sosnovsky's hogweed modified with borazote for biostability with the use of organopolymer binders. The particle size of the plant material varied from 1 to 10 mm. Polyvinyl acetate, polyurethane, and casein were used as binders. The ratio of the components (vegetable raw material: polymer) in the composites was 3:1 by mass. Biostability and thermophysical properties of the composites obtained were investigated by applying appropriate GOST methods. It was established that the preliminary modification of vegetable raw material particles with monoethanolamine (NB)-trihydroxyborate provides 100% biostability of composite materials based on used raw materials and organopolymer binders. The use of the above modifier is equally effective for all composites obtained using different types of binders: polyurethane, polyvinyl acetate, and casein. The composites obtained on the basis of modified plant raw materials and organopolymer binders are heat-insulating materials characterized by appropriate coefficients of thermal conductivity and density. Composites based on polyurethane binders have lower thermal conductivity compared to composites based on polyvinyl acetate and casein binders and belong to class A. The polyurethane binder provides the resulting composites with a particle size of 5 mm with an increased compressive strength as compared to the composites based on polyvinyl acetate and casein binders. Thus, the optimal composition of biostable heat insulating material is the composition based on modified plant raw materials with a particle size of 5 mm and polyurethane binder.

Construction technology and raw materials for the restoration of Gian Lorenzo Bernini's Cornaro Chapel Vault, Rome (Italy)

Objective: A comparative study was carried out to determine the reinforcement efficiency of palm fruit fibre (PFF) and coconut fibre (CNF) in high-density polyethylene (HDPE) composites. Method: For both fibres the physical properties such as bulk density, pH, and particle size were first assessed. Then mechanical tests such tensile strength and impact strength were also carried out. Results: PFF had higher bulk density (99.20 kg/m³) and pH (9.00), while CNF had greater particle size (6.10 kJ/m²) and moisture content (5.32%). Mechanical testing revealed that PFF significantly enhanced tensile strength (up to 22.56 N/m²) and impact strength (1.26 kJ/m²) at 10–20 g loading, but reduced abrasion resistance and elongation at break. CNF also improved tensile (21.88 N/m²) and impact strength (1.01 kJ/m²) at 10 g, but caused greater reductions in abrasion resistance and a more substantial increase in water absorption, reaching 43.01% at 20 g. Solvent absorption tests showed a general increase in kerosene, petrol, and diesel uptake with higher fibre content for both composites. PFF composites showed the highest petrol absorption (25.12%) at 20 g, while CNF composites exhibited greater overall solvent and water uptake. The findings indicate that PFF offers better mechanical reinforcement, while CNF shows higher fluid affinity. Conclusion: The choice between fibres should therefore depend on whether mechanical performance or resistance to moisture and solvents is prioritized in the intended application.

Clay had been used as binders in briquetting research activities, however their performance characterization in terms of quality and combustion have not been clearly evaluated or reported. This study therefore provide a qualitative evaluation of briquettes produced using sawdust of Gmelina arborea and montmorillonite clay. Sun-dried sawdust (~9% moisture contents) obtained from sawmills in Ishiagu, Ebonyi State were mixed with processed clay samples collected from earthen pot mould sites characterized, then used in briquette production using five mixing ratios of 90:10, 80:20, 70:30, 60:40, & 50:50 (weight/weight)% and standard test procedures for characterization. Data were analyzed using SPSS at p< 0.05 significance levels. The quality characteristics of clay briquettes compared favourably with other binder types with an increase in performance as binder concentration increases. The briquettes combustion performance in air and stove are significantly affected by the agglomerated non-combustible clay particle impregnating the biomass matrix. Best combustion performance occurred at 10% binder concentration with no significant value-addition to ignition time, flame combustion and heating values. Above 10% binder addition, briquettes failed self-ignition, flame combustion, and retarded char combustion tests. This implied clay is a poor performing binder and the associated briquette are combustibly poor.

1. It was established in this investigation that, when 15% nickel is added to an iron-copper-graphite alloy containing after sintering 1.1% C and 10% Cu, the hardness of the alloy increases by 20–25%, but, at the same time, its mechanical strength, ductility, and impact strength decrease compared with the same properties of a similar nickel-free alloy. 2. Other conditions being equal, sintering in a dissociated ammonia atmosphere reduces the mechanical and impact strengths by approximately 10–15% and slightly decreases the ductility compared with the properties of the same alloy sintered in a hydrogen atmosphere. 3. The tensile and impact strength tests of specimens at 400°C revealed a slight decrease in the mechanical and impact strengths at that temperature. 4. The thermal conductivity increases linearly with increasing temperature. The Lorenz function is greater than its theoretical value, and decreases with increasing temperature. This indicates that heat conduction in this alloy is due to conduction electrons and crystal-lattice conduction. 5. The coefficient of linear thermal expansion at first shows an insignificant increase, but at 400°C attains values characteristic of cast austenite.

Autoclaved Aerated Concrete (AAC) is a special composite and widely accepted construction material owing to good durability, raw material availability, and environmentally friendly nature. Nevertheless, the continuing focus of the industry remains in cost optimization and maximizing the performance of blocks. The investigations related to the effects of admixtures in AAC are continuing globally with the objective of improving the productivity and strength improvement of AAC blocks. It is now well documented that the behavior of admixtures in conventional concrete and AAC is different, partly due to the low quantities of cement in a mix design and production systems. Hence it is essential to conduct a detailed investigation for finding the suitability of chemical admixtures. This review paper shows the trend of admixtures used in AAC and describes how they affect the rheological characteristics, setting time, and mechanical properties. From the review, it is clear that the performance of admixtures mainly depends on the type of binder, type, and dosage of admixtures. PCE‐based superplasticizers and performance enhancers are generally recommended to provide incremental improvement in flow behavior and mechanical strength. However, it is important to note the mix design and complex interplay of various materials have a large impact on the performance of any admixture employed. The investigations thus far indicate that chemical admixtures also impact the initial curing times without sacrificing the mechanical properties of AAC. In general, the usage of admixtures can enhance the strength of blocks between 5% and 15% depending on the type and quantity of admixture.