The ‘Green’ Ni-UGSO Catalyst for Hydrogen Production under Various Reforming Regimes

A new spinelized Ni catalyst (Ni-UGSO) using Ni(NO3)2·6H2O as the Ni precursor was prepared according to a less material intensive protocol. The support of this catalyst is a negative-value mining residue, UpGraded Slag Oxide (UGSO), produced from a TiO2 slag production unit. Applied to dry reforming of methane (DRM) at atmospheric pressure, T = 810 °C, space velocity of 3400 mL/(h·g) and molar CO2/CH4 = 1.2, Ni-UGSO gives a stable over 168 h time-on-stream methane conversion of 92%. In this DRM reaction optimization study: (1) the best performance is obtained with the 10–13 wt% Ni load; (2) the Ni-UGSO catalysts obtained from two different batches of UGSO demonstrated equivalent performances despite their slight differences in composition; (3) the sulfur-poisoning resistance study shows that at up to 5.5 ppm no Ni-UGSO deactivation is observed. In steam reforming of methane (SRM), Ni-UGSO was tested at 900 °C and a molar ratio of H2O/CH4 = 1.7. In this experimental range, CH4 conversion rapidly reached 98% and remained stable over 168 h time-on-stream (TOS). The same stability is observed for H2 and CO yields, at around 92% and 91%, respectively, while H2/CO was close to 3. In mixed (dry and steam) methane reforming using a ratio of H2O/CH4 = 0.15 and CO2/CH4 = 0.97 for 74 h and three reaction temperature levels (828 °C, 847 °C and 896 °C), CH4 conversion remains stable; 80% at 828 °C (26 h), 85% at 847 °C (24 h) and 95% at 896 °C (24 h). All gaseous streams have been analyzed by gas chromatography. Both fresh and used catalysts are analyzed by scanning electron microscopy-electron dispersive X-ray spectroscopy (SEM-EDXS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) coupled with mass spectroscopy (MS) and BET Specific surface. In the reducing environment of reforming, such catalytic activity is mainly attributed to (a) alloys such as FeNi, FeNi3 and Fe3Ni2 (reduction of NiFe2O4, FeNiAlO4) and (b) to the solid solution NiO-MgO. The latter is characterized by a molecular distribution of the catalytically active Ni phase while offering an environment that prevents C deposition due to its alkalinity.

Optimization of Blast Furnace Throughput Based on Hearth Refractory Lining and Shell Thickness

Computational analyses were performed to optimize the furnace throughput, steel shell and lining thickness of a blast furnace. The computations were done for measured parameters within the hearth region as this is the vital zone of the furnace with high temperature fluctuations, molten iron, and slag production. The lining materials were namely 62% high alumina (A), carbon composite (B), silicon carbide (C) and graphite bricks (D) with thermal conductivities 2, 12, 120 and 135 W/(m∙K), respectively. It was observed that by varying the refractory lining thickness from 0.2–0.35 m, and furnace inside temperatures from 1873–2073 K, certain optimal conditions could be specified for the furnace under consideration. Silicon carbide and graphite brick linings which have higher thermal conductivities, melting points, good chemical and mechanical wear resistance were observed to be the best hearth lining materials. Due to the high thermal conductivities of these two materials, the hot face temperature levels of the lining materials would be lowered. Amongst the four lining materials employed, silicon carbide and graphite bricks when used with lining cooling systems could optimize the blast furnace for better performance, production, and longer campaigns.

Modeling Viscosity of High Titania Slag

TiO2-FeO-Ti2O3 slag system is the dominant system for industrial high-titania slag production. In the present work, viscosities of TiO2-FeO and TiO2-FeO-Ti2O3 systems were experimentally determined using the concentric rotating cylinder method under argon atmosphere. A viscosity model suitable for the TiO2-FeO-Ti2O3 slag system was then established based on the modification of the Vogel-Fulcher-Tammann (VFT) equation. The experimental results indicate that completely melted high-titania slags exhibit very low viscosity of around 0.8 dPa s with negligible dependence on temperature and compositions. However, it increases dramatically with decreasing temperature slightly below the critical temperature. Besides, the increase in FeO content was found to remarkably lower the critical temperature, while the addition of Ti2O3 increases it. The developed model can predict the viscosities of the TiO2-FeO-Ti2O3 and TiO2-FeO systems over wide ranges of compositions and temperatures within experimental uncertainties. The average relative error for the present model calculation is < 18.82 pct, which is better than the previously developed models for silicate slags reported in the literature. An iso-viscosity distribution diagram was made for the TiO2-FeO-Ti2O3 slag system, which can serve as a roadmap for the Ilmenite smelting reduction process as well as the high titania slags tapping process.

Factor Analysis of Training, Knowledge, Supervision, and Unsafe Actions on Occupational Accidents at PT X

Introduction: Industrial accidents are accidents occurring in the workplace, especially in the industrial environment. According to the data, the occupational accidents at PT X in RKC (raw mill, kiln, cooler) Operational Section of Slag Production are still found annually. From 2015 to 2017, there had been nine occupational accidents recorded. There was one occupational accident in 2015, five occurrences in 2016, and three occurrences in 2017. This study aimed to analyze the factors of supervision, training, knowledge, and unsafe actions that can lead to occupational accidents suffered by the workers in RKC Operational Section of Slag Production at PT X. Methods: This study was a cross-sectional study with a population of 19 people by implementing the descriptive test analysis to describe the percentage of each observed dependent variable. Results: This study revealed that 78.9% of the workers claimed that the supervision was good, 73.7% agreed that the training was good, 57.9% agreed that they had good knowledge, and 52.6% claimed to conduct unsafe actions in moderate level. Conclusion: the factors of supervision, training, and knowledge were influential to the occurrence of occupational accidents, yet they remained within the tolerable level since almost all workers performed in the good category in those categories. On the other hand, unsafe actions had a considerable influence on the occurrence of occupational safety and health since the majority of the workers performed unsafe actions moderately. Keywords: factor analysis, occupational accidents, unsafe actions

Development of the organization of rational schemes for the use of technogenic waste in the processes of off-treatment of steel intermediate

The results of the experimental verification of the efficiency of complex out-of-furnace treatment of low carbon steel using a test mixture based on man-made waste, which is fed partly to the melting unit at the end of the oxidation period of melting and partly by pouring under a stream of liquid metal. is the use of slag-forming materials obtained by joint heat treatment of mixtures of components containing the above mentioned oxides and carbonaceous material of vegetable origin. Their weight ratio in the initial mixture is determined by the purpose and properties of the finished product. The positive technological effects that are achieved by applying the developed method of after-treatment will in future provide favorable conditions for the effective conduct of microalloying, modification, vacuuming and stable casting of low-quality and ultra-low carbon steel. A slight decrease in the temperature of the steel intermediate in the implementation of the method is about 10 - 15 ° C, which is easily compensated for the installation of the ladle, and a slight increase in electricity consumption is compensated by the effects achieved in the processing of low-carbon steel intermediate. Obtaining a higher degree of desulfurization and deoxidation of steel, as well as reducing the contamination of Al2O3 steel and improving the ecological purity of the process can be achieved by reducing the composition of the SHS used in the first stage of processing, the amount of slag aluminothermal production of ferromanganese and complete exclusion of melting, melting weight ratios of powdered waste production of lime, aluminum-thermal slag production of ferromanganese, sludge neutralization of electrocorundum and carbide cr emnia.

Synthetic Slag Production Method Based on a Solid Waste Mix Vitrification for the Manufacturing of Slag-Cement

Herein an innovative process to develop a potential vitreous material with cementing properties is proposed. This process paves a production path through melting industrial waste and subsequently cooling the casting in water. The idea erases the need to reduce the environmental impact of the cement industry in terms of natural resources consumption as well as the re-utilization of abandoned wastes from other industries. The recycled industrial wastes were selected according to the amount of waste produced in the industrial field and its suitable chemical composition, such as construction and demolition waste and/or shells from shellfish. As a main result, the mechanical properties showed by our novel material were worse than those reported by blast furnace slag (25–28 MPa for two different proportions) for seven days and better (43–52 MPa for two different proportions) for 28 days. The rest of the properties evaluated were in agreement with the standards’ requirements. Hence, this novel process would help to minimize the environmental impact of these wastes at the same time that their use in the cement industry would reduce the consumption of raw materials.