Synthesis of Sustainable and High Purity of Quicklime Derived from Calcination of Eggshell Waste in a Laboratory-Scale Rotary Furnace

Quick lime or calcium oxide has attracted significant attention as a sustainable material to be used as fillers and catalysts in a broad range of industries. The quick lime derived from calcination of eggshell waste in a laboratory-scale rotary furnace is reported in this study. The eggshell waste was prepared by washing several times, drying in the sun, grinding and sieving through a 250 micrometers sieve size. Calcination of the sieved eggshells waste was conducted in a single zone rotary tube furnace at 800 °C with 5 degree slope and at 1 rpm. Both physical and chemical properties of the calcium oxide derived from the calcination of eggshell waste were systematically investigated by various scientific instruments. The results from powder X-Ray Diffraction (PXRD) and X-Ray Fluorescence: (XRF) showed that most of the calcium carbonate in the eggshell waste was thermally transformed to nano-calcium oxide with mean crystallite size of 47.5 nm and with a purity of 97.8%. The results from this study indicated the optimum conditions and the possibility for mass production of nano-calcium oxide via rotary furnace and have shown that the obtained nano-calcium oxide is comparable to the commercial chemical.

ROTARY FURNACE LINING TO REDUCE THERMAL STRESS

The aim of the study is to reduce the thermal stresses of the lining in the areas adjacent to the flare sintering zone of rotary kilns intended for the production of cement clinker. It is proposed to use a lining made of parallel rows of alternating chamotte and chromium-magnesite refractory products to reduce thermal stresses in the areas adjacent to the flare sintering zone by up to 20%, increase the service life of the lining by 1.1-1.2 times as a result of equalizing thermal stresses in the areas of the sintering zone. Optimization of the initial raw material mixture, in turn, made it possible to reduce the temperature of clinker formation and led to fuel savings.

Research on Reduction of Selected Iron-Bearing Waste Materials

During the steel production process, nearly twice as many input materials are used as compared to finished products. This creates a large amount of post-production waste, including slag, dust, and sludge. New iron production technologies enable the reuse and recycling of metallurgical waste. This paper presents an investigation on the reduction of selected iron-bearing waste materials in a laboratory rotary furnace. Iron-bearing waste materials in the form of dust, scale, and sludge were obtained from several Polish metallurgical plants as research material. A chemical analysis made it possible to select samples with sufficiently high iron content for testing. The assumed iron content limit in waste materials was 40 wt.% Fe. A sieve analysis of the samples used in the subsequent stages of the research was also performed. The tests carried out with the use of a CO as a reducer, at a temperature of 1000 °C, allowed to obtain high levels of metallization of the samples for scale 91.6%, dust 66.9%, and sludge 97.3%. These results indicate that in the case of sludge and scale, the degree of metallization meets the requirements for charge materials used in both blast furnace (BF) and electric arc furnace (EAF) steelmaking processes, while in the case of reduced dust, this material can be used as enriched charge in the blast furnace process. Reduction studies were also carried out using a gas mixture of CO and H2 (50 vol.% CO + 50 vol.% H2). The introduction of hydrogen as a reducing agent in reduction processes meets the urgent need of reducing CO2 emissions. The obtained results confirm the great importance and influence of the selection of the right amount of reducer on the achievement of a high degree of metallization and that these materials can be a valuable source of metallic charge for blast furnace and steelmaking processes. At an earlier stage of the established research program, experiments of the iron oxides reduction from iron-bearing waste materials in a stationary layer in a Tammann furnace were also conducted.

Improving the Reliability of Rotary Furnace Drums By Stabilizing the Temperature Regime By Effect of Electromagnetic Fields

The unevenness of the heat flow generated in the furnaces of the drums of rotary kilns leads to damage to the drum casing, which can cause premature failure. The author suggests that by deflecting the flame by applying electromagnetic fields, it is possible to prevent direct contact between the flame and the furnace drum, extending the latter’s service life. In this way, it is possible to regulate the directions of movement of the heated combustion products to realize the uniform distribution of heat fluxes, as well as to regulate local temperature fields in real time. The study took into account 5 main factors of the influence of the electromagnetic field on the flame. Based on the studies, a description of a device partially integrated in the furnace is proposed. In this case, there is no significant constructive modernization of the furnace. This device is an analogue of a high-temperature fan, but has several advantages in comparison with it. Keywords: electromagnetic field, furnace, flame, heat exchange

The Effect of Palm Kernel Shell Ash on the Mechanical and Wear Properties of White Cast Iron

This study investigates the influence of palm kernel shell ash (PKSA) on mechanical and wear properties of white cast iron (WCI) particularly its influence on its microstructure, elemental composition, hardness and wear resistance. The PKSA was characterized to determine its elemental composition, and it was found to contain high amount of silicon (Si) and iron (Fe) followed by calcium (Ca) and other trace elements. The cast iron was cast into rods of specific dimension with sand casting method using rotary furnace to re-melt cast iron scrap. The WCI rods were then cut into bits for the various test. Heat treatment operation was carried out to determine its properties. Upon completion of the examinations, it was found that the PKSA increased the cementite phase within the matrix of the cast iron, and reduced the pearlitic phase and graphite formation, which gave it increased hardness, and perfect wear resistance due to the increment in carbon content and reduction in silicon content. Also, upon heat treatment, it was found that the PKSA reduced the pearlitic phase within the matrix of the cast iron, increases the formation of transformed ledeburites, austenitic dendrites and tempered graphite, which lead to increased machinability and ductility as well as to reduced hardness, and wear resistance when compared to non-heat treated samples.

Modeling and Optimization of Experimentally Verified Effect of Preheated Excess Air on Fuel Consumption of Rotary Furnace using PSO (Particle Swarm Optimization) Technique

The energy consumption in ferrous foundries has been reported as a serious concern. The prevailing natural sources may not last long. By the time of availability of new resources we have to optimize the usage of prevailing resources to avoid serious conditions later on.The authors have attempted to analyze the effect of aspects of combustion of furnace oils in an oil fired rotary furnace with highly preheated air, and to verify the experimental results using PSOM (Particle Swarm Optimization) technique. The authors conducted a series of experiments on an oil fired rotary furnace of 200 kg capacity installed in a leading ferrous foundry. Detailed in measurements of temperature, and heat transfer, flame temperature, fuel consumption etc has been performed. During experimentation furnace was supplied with 10% excess air, preheated using multipass counter flow heat exchanger. The experimental investigations revealed that using 10% excess air drastically reduces the fuel consumption, increase melting rate, and the heat transfer rates due to enhanced flame temperature. The PSOM (Particle Swarm Optimization) technique also verified the experimental results.

Surface Characteristics of Different Wood and Coal-Based Activated Carbons for Preparation of Carbon Molecular Sieve

In this study, four different nanostructures precursors, pistachio wood, walnuts wood, forest wood and coal (Anthracite) were selected to produce activated carbon. The experiments were done in industrial scale using a rotary furnace with temperature between 850 and 920 ºC for 45 minutes followed by steam. The product was grounded and divided in three particle sizes, 8x30, 30x50, and 60x80 meshes. The physical properties and surface chemistry of the activated carbon samples were determined by imaging of BET-N2 adsorption. The results obtained from measurements of iodine and methylene blue numbers, surface area, pore volume and comparison of surface area and pore volume, show that by decreasing of particle sizes of each sample, increase the surface area and micro pore volumes significantly. The magnitude of changes in surface area with particle size is a significant factor in defining the effectiveness and suitability of an activated carbon for the production of carbon molecular sieve. Our results indicate that the highest pore volume belongs to pistachio wood, which was increased from 0.168 to 0.271 cm3/g from 8x30 to 60x80 mesh. Resumen. En este estudio, se seleccionaron cuatro precursores de nanoestructuras diferentes, madera de pistache, madera de nueces, madera de bosque y carbón (antracita) para producir carbón activado. Los experimentos se realizaron a escala industrial utilizando un horno rotatorio con una temperatura entre 850 y 920 ºC durante 45 minutos, seguido de vapor. El producto se molió y se dividió en tres tamaños de partículas, en mallas de 8x30, 30x50 y 60x80. Las propiedades físicas y la química de la superficie de las muestras de carbón activado se determinaron mediante imágenes de la adsorción de BET-N2. Los resultados obtenidos de las mediciones de los números de yodo y azul de metileno, área de superficie, volumen de poros y comparación de área de superficie y volumen de poros muestran que, al disminuir los tamaños de partícula de cada muestra, aumenta significativamente el área de superficie y los volúmenes de microporos. La magnitud de los cambios en el área de la superficie con el tamaño de partícula es un factor significativo en la definición de la efectividad y la idoneidad de un carbón activado para la producción de tamiz molecular de carbono. Nuestros resultados indican que el mayor volumen de poros pertenece a la madera de pistache, que aumentó de la malla de 0.168 a 0.271 cm3/g de 8x30 a 60x80.