The impact of torrefaction temperature on the ignitability, fuel ratio and ash fusion temperatures of two tropical deciduous woods (Teak and Melina) were investigated in a setup of tubular furnace. The properties considered are calorific value, fuel ratio, ignitability index, ash compositions and ash fusion temperatures of the biomass. Six different temperatures (220, 240, 260, 280, 300 and 320 °C) at 60 min reaction time were considered. The results indicated that as torrefaction temperature increased, the calorific value, fuel ratio and ignitability index of the biomass also increased. The ignitability index of biomass (40-63) was better than the value (35) recommended for fuel applicable in thermal plants for power generation. The ash compositional analysis revealed that there was no variation in the quantity of SiO₂, Al₂O₃, CaO along with other minerals for the raw and torrefied biomass. This implied that the temperature up to 320 °C has no significant impact on the compositions of biomass ash during torrefaction. The ash fusion temperature test showed that the biomass ash softens at ≈ 1200 °C and finally fused at ≈ 1300 °C. The study concluded that an increase in torrefaction temperature increases the thermal properties of the torrefied biomass without affecting the compositions of biomass ash or lowering the ash fusion temperatures.

The utilization of agro-residues ash as complementary reinforcing materials continues to gain prominence for metal matrix composite (MMCs) development. A rarely investigated but largely available ash among these agro-residues is the palm kernel shell ash (PKSA). Thus, the present study investigates the influence of PKSA particulates hybridized with SiC on the physico-mechanical properties and microstructure of Al6063 metal composites. The composites are synthesized using the double stir-casting technique with SiC held constant at 2 wt.%, while the PKSA contents are varied from 0 to 8 wt.%. The phases present and morphology of the composites are investigated using X-ray diffractometer (XRD) and scanning electron microscopy (SEM), respectively. The density, porosity, hardness, tensile and fracture toughness tests are carried out on the hybrid composites. X-ray diffractometer revealed that for Al 6063, only Al cubic crystal system was identifiable within the matrix. However, for the reinforced composites, major phases identified are Al, Fe₃Si, SiC, MgO, and SiO₂. The SEM images show that the particulates reinforcements (SiC and PKSA) were uniformly dispersed in the matrix. The percentage porosity for the composites ranged from 2.06 to 2.39%. In addition, hardness, yield strength and ultimate tensile strength of the composites are about 10.3%, 18.5% and 10.4%, respectively better than for Al 6063. However, the percent elongation and fracture toughness are lower for the hybrid composites than for Al 6063 and SiC reinforced composite with values decreasing with increase in ash content. Hence, the MMCs produced will be applicable for light-weight engineering applications.

Coal processing industries generate millions of tons of fines (<3 mm) during mining operation and are often considered as wastes. These wastes have enormous potential in serving as energy and metallurgical operation feedstock. One avenue for its use is densification into briquettes or pelletizes. Various briquetting techniques have been adopted in the past few decades; however, the main issues upfront in commercializing these techniques are significant binder cost and poor mechanical integrity. Therefore, the present study concentrates on utilizing commonly available organic binder along with pretreated biomass in developing coal fine briquettes. Briquettes were produced after initial pretreatment of the raw materials under a load of 2 tons. Briquettes were cured in an inert environment and eventually characterized for its main litmus requirements (physical properties). It was observed that pitch-molasses bonded briquettes have better physical properties leading to good mechanical integrity than briquettes produced from individual binder. The proximate, ultimate and calorific value analyses of the briquettes do not deteriorate but mildly improved compared to the raw coal fines. With a density of 1.18-1.32 g/cm³, drop to fracture that is greater than 100 (times/2 m), impact resistance index well above 6000, water resistance index of 99% and cold crushing strength of 9 MPa, pitch-molasses bonded briquettes clearly surpassed recommended physical properties benchmarked for briquettes of industrial and domestic end use. The physical properties of the briquettes favorably meet requirements as feedstock for rotary kiln direct reduced iron and COREX iron-making processes as well as fuel for thermal operations.