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The reaction kinetics, activation energy, and reduction rates of different carbon reductant properties with electric arc furnace (EAF) slag determine the effectiveness of carbon in EAF steelmaking. This article investigates the interaction between slag and carbonaceous materials derived from palm char and coke. Palm shells were converted into palm char using chemical activation method (phosphorus acid, H3PO4) and pyrolyzed at 450 °C for 2 h in a horizontal tube furnace. Then, all the carbonaceous materials were mixed with iron oxide from slag with mass ratio of 1:3.73. The reduction reaction was carried out in a horizontal tube furnace at different temperature ranges of 1250–1550 °C under argon gas to understand the reaction kinetics, activation energies, and reduction rates of iron oxide from EAF slag with palm char and coke. All iron oxides in EAF slag were completely reduced into metallic iron at 1550 °C for both reductants. The phase and quantity of reduced iron were confirmed by Rietveld refinement method using X-ray diffraction (XRD) pattern and energy-dispersive X-ray spectroscopy (EDX). Palm char/slag has lower activation energy value, E (38.52 kJ/mol), than coke/slag (47.75 kJ/mol). The reaction rate of palm char was found faster (4.99 × 10–5 mol/cm2 s) than coke due to larger specific surface area, higher pore volume, amorphous carbon structure, and higher fixed carbon with high volatile content leading to lower activation energy, thus accelerating the iron oxide reduction rates. This finding forms the basic understanding of the reaction between EAF slag and carbonaceous materials for future research on the production of palm char as a feasible carbon reductant in EAF steelmaking.

Agricultural wastes generated from palm and coconut shells could be renewable carbon sources in steelmaking by providing the solution to environmental problems and reducing the gas emission. By applying these wastes as carbon reductant at steelmaking’s temperature, the determination of the reduction-controlling reaction rate is necessary. Thus, the present study aims to provide an understanding of the effect of high temperature (1823 K) on the reduction-controlling reaction rate of palm and coconut chars that reacted with steelmaking slag. Palm and coconut shells were pyrolyzed at 723 K under nitrogen inert for char conversion. The char has a porous structure and contains high volatile matter that is more chemically active in the system reaction compared to coke. All carbonaceous materials including coke as a control carbon mixed with steelmaking slag using an infrared (IR) gas analyzer to measure the amounts of carbon dioxide (CO2) and carbon monoxide (CO) gases produced after reduction. The reaction rate of palm and coconut chars after reaction with steelmaking slag was lower (0.93721 × 10−5 and 0.30563 × 10−5 mol cm−2 s−1) than that of coke (2.16283 × 10−5 mol cm−2 s−1) due to lower fixed carbon content that retards the reaction rate. The reaction using palm and coconut chars approached faster the equilibrium of the carbon solution-loss reaction (C + CO2 → 2CO) and Boudouard equilibrium where the reaction reached the equilibrium value of 1.0 than coke due to higher CO generation. The results found that agricultural waste char is used as a carbon reductant in iron oxide reduction of steelmaking slag in a cleaner and sustainable production of iron due to their better properties such as volatile matter and porous structure.

Carbonate rocks were mechanically activated in a high energy planetary ball mill using dry grinding method. The fine grinding test works were carried out with the same ball to powder ratio (9:1) at three levels of revolution speed (250 rpm, 350 rpm and 450 rpm) and grinding time (30 min, 60 min, 90 min) respectively. The chemical composition and elemental constituents of the raw dolomite and limestone samples were determined using X-ray fluorescence (XRF) and energy dispersive X-ray spectroscopy (EDX). The structural properties such as degree of crystallinity (DOC), crystallite sizes and lattice strains of non-activated and mechanically activated carbonate rocks were analyzed using X-ray diffraction (XRD) while the morphological analysis conducted using scanning electron microscopy (SEM). Results obtained showed that high revolution speed and longer grinding duration have pronounced effect on the grindability, increase in fineness, decrease in crystallite sizes and amorphization of Perlis dolomite compared to the limestone source. This might be due to the difference in material hardness and existence of appreciable amount of quartz content in limestones.

This research focused on the synthesis of ferrosilicon alloy by coke and palm char as a reductant. Raw materials which were iron ore, silica sand, coke and palm char mixed and compacted into pellets. The pellets were reduced at temperature of 1300°C using horizontal tube furnace with nitrogen gas flow. The pellets after reduction process were characterized by X-ray fluorescence (XRF), X- ray diffraction (XRD), Scanning electron microscope equipped with energy dispersive spectra (SEM/EDS). The results from XRD analysis indicated that the formation of FeSi, Fe3Si and SiC phases were appeared at 1300 °C for both reductants. The brighter phases were observed in SEM/EDS mapping analysis represents as iron and silicon. The EDX analysis showed the high amount silica developed for coke compared to palm char due to high content of silica and carbon. The results found that palm char as carbon reductant has the potential to produce ferrosilicon and silica carbide in sustainable way.

This paper presents on the structural changes associated with mechanical activation of limestone (CaCO3) and dolomite (CaMg(CO3)2) from Perlis, Malaysia via Planetary ball milling. Operational variables include 3 level of revolution speed (250, 350 and 450 rpm), grinding durations (30, 60 and 90 min) and ball to powder ratios BPR (3:1. 6:1 and 9:1) respectively. The chemical compositions of both mineral samples were determined with XRF technique while the structural properties and morphological characteristics identified using XRD and SEM methods. The structural changes such as amorphization, decline in crystallite size (CS), degree of crystallinity (DOC) and morphological alterations are closely related to the operational parameter and the mineral constituents such as quartz content. Overall, the crystallite size of limestone and dolomite ranges from 60.74 to 25.15 nm and 45.65 to 22.07 nm respectively. Accordingly the DOC was reduced from 100 to 31.69% in CaCO3 and 36.55% in (CaMg(CO3)2).