Sand casting is the most widely used casting technique, known for ages, even since ancient times. The main goal of this study was to determine the thermal decomposition behaviour of foundry sand for ...cast steel. We first tested the basic properties of foundry sand, including its proximate analysis, chemical composition, and particle size characteristics; we next monitored the thermal decomposition behaviour of foundry sand for cast steel via simultaneous thermal analysis. We focused on the mass loss of foundry sand for cast steel at different heating rates in nitrogen and air atmospheres. We adopted a novel method to calculate the volatile release characteristic index of foundry sand. The volatile content of foundry sand for cast steel was very low, so the volatile release characteristic index of the sand could not be strictly calculated according to this concept. We calculated the thermal decomposition kinetics parameters of foundry sand, namely, the activation energy and preexponential factor, under kinetics theory. To thoroughly test the fitting effect, we conducted a single-factor analysis of variance on the source of error. The results showed that the independent variable has a significant influence on the dependent variable and that the fitting equation we selected is feasible and effective.
The method of the ongoing assessment of the reclaim quality originating from the mechanical reclamation is described in this paper. In the process, the triboelectric system of measuring amounts of ...dust in the dedusting part of a reclamation device was applied. Based on the online measurements of the amounts of dust generated in the spent sand-reclamation process and the post-process determinations of the ignition losses and granular structures of the removed dust, the proper work parameters of the experimental reclaimer were selected. The allowable value of the ignition losses as well as the main fraction of the reclaimed matrix being similar to fresh sand was assumed as the main criteria of the positive assessment of the process. Within the presented investigations, a periodically operating device for rotor-mechanical reclamation was developed. The possibility of changing the intensity and time of the reclamation treatment as well as the triboelectric system of the dust-amount measuring were applied in this device. Tests were performed for the spent moulding sand with phenol-resol resin Carbophen 5692 hardened by CO2. This sand represents the moulding sand group with a less harmful influence on the surroundings for which the recovery of the quartz matrix utilising the reclamation requires stricter control of the parameters of the reclamation process and reclaim quality.
Various building infrastructure projects worldwide have resulted in a significant rise in the production of waste materials such as concrete, fly ash, plastic, rice husk, foundry sand, and other ...materials, raising disposal issues. Crushed concrete is abundant and comes from the removal of old buildings as well as waste concrete from new construction. As a result, construction waste recycling is essential, both in reducing the amount of open land needed for landfilling and environmental protection by resource conservation. The research’s main objective is to study the effect of adding sodium silicate on the cohesion strength of crushed concrete and its behavior. the concrete cubes are grinded with a hammer to get crushed concrete which passing sieve no 4. The results show that the cohesion strength increase as a percentage of sodium silicate increase (addition 6% Sodium silicate show the higher strength where the strength increased at 10 days by 246% and at 14 days by 250% as compared with strength at 5 days) and the cohesion between crushed concrete particles increase until 8% sodium silicate the cohesion began to decrease (10% same cohesion at 2%). As well, the cohesion strength increase when curing time increase.
In this paper, oil recovery mechanisms and asphaltene precipitation phenomenon of immiscible and miscible COsub 2 flooding processes in the tight sandstone reservoir core plugs are experimentally ...studied. First, the vanishing interfacial tension (VIT) technique is applied to determine the minimum miscibility pressure (MMP) between the original light crude oil and COsub 2. Second, a total of five coreflood tests are performed at the actual reservoir temperature. Finally, the experimental results obtained in this study at the actual reservoir temperature of Tsubres=53.0degreesC are compared with those attained previously at the laboratory temperature of Tsublab=27.0degreesC to examine the temperature effect on the COsub 2-based oil recovery process.
The aim of this research was to evaluate the possibility of reusing waste foundry sands derived from the production of cast iron as a secondary raw material for the production of building materials ...obtained both by high-temperature (ceramic tiles and bricks) and room-temperature (binders such as geopolymers) consolidation. This approach can reduce the current demand for quarry sand and/or aluminosilicate precursors from the construction materials industries. Samples for porcelain stoneware and bricks were produced, replacing the standard sand contained in the mixtures with waste foundry sand in percentages of 10%, 50%, and 100% by weight. For geopolymers, the sand was used as a substitution for metakaolin (30, 50, 70 wt%) as an aluminosilicate precursor rather than as an aggregate to obtain geopolymer pastes. Ceramic samples obtained using waste foundry sand were characterized by tests for linear shrinkage, water absorption, and colorimetry. Geopolymers formulations, produced with a Si/Al ratio of 1.8 and Na/Al = 1, were characterized to evaluate their chemical stability through measurements of pH and ionic conductivity, integrity in water, compressive strength, and microstructural analysis. The results show that the addition of foundry sand up to 50% did not significantly affect the chemical-physical properties of the ceramic materials. However, for geopolymers, acceptable levels of chemical stability and mechanical strength were only achieved when using samples made with 30% foundry sand as a replacement for metakaolin.
In order to study the effect of the micro‐CT scan resolution and size on the accuracy of upscaled digital rock property estimation of core samples Bentheimer sandstone images with the resolution ...varying from 0.9 μm to 24 μm are used. We statistically show that the correlation length of the pore‐to‐matrix distribution can be reliably determined for the images with the resolution finer than 9 voxels per correlation length and the representative volume for this property is about 153 correlation length. Similar resolution values for the statistically representative volume are also valid for the estimation of the total porosity, specific surface area, mean curvature, and topology of the pore space. Only the total porosity and the number of isolated pores are stably recovered, whereas geometry and the topological measures of the pore space are strongly affected by the resolution change. We also simulate fluid flow in the pore space and estimate permeability and tortuosity of the sample. The results demonstrate that the representative volume for the transport property calculation should be greater than 50 correlation lengths of pore‐to‐matrix distribution. On the other hand, permeability estimation based on the statistical analysis of equivalent realizations shows some weak influence of the resolution on the transport properties. The reason for this might be that the characteristic scale of the particular physical processes may affect the result stronger than the model (image) scale.
Key Points
Correlation length of pore‐to‐matrix distribution is statistically reliably determined for resolution finer than 9 voxels per correlation length
The statistically representative volume for pore‐to‐matrix distribution is about 15 correlation lengths
The representative volume for the transport property calculation should be greater than 50 correlation lengths of pore‐to‐core distribution
In a post-pandemic world, health and environmental safety will become a more important issue than it was before the COVID-19 pandemic. Several fields of engineering, including the foundry industry, ...have already adopted health and safety measures in the workplace. The risk of pulmonary disease caused by the inhalation of fine particles of silica sand, the main moulding material used in the foundry industry, is rampant in that industry. In terms of environmental protection, the new regulatory restrictions on the disposal of used sand create the need for moulding aggregates to be more recyclable than silica. Chromite sand is an alternative refractory sand for metal casting applications, and is abundant in South Africa. The present study investigated whether this aggregate has better overall reusability than silica. The focus of this study is on the use of chromite sand in foundries as a contribution to improving health in the workplace and to reducing the environmental impact of foundry sand.
Novel composite materials composed of clay, foundry sand (FS), and fly-ash (FA) have been employed to immobilize TiO
2
for incorporating in-situ dual effect for the degradation of antibiotic ...ofloxacin. The in-situ generation of iron from the composite beads with surface active TiO
2
induced the dual effect of photo-Fenton and photocatalysis. FA/FS/TiO
2
beads illustrated the best results (92% removal) at optimized conditions in the batch reactor experiments. The increment in the rate constant along with a decrease in treatment time for the dual effect has proven the credentials of the in-situ dual effect. Synergy in first-order rate constant using dual process was 51% over the single processes of photo-Fenton and photocatalysis. After 35 recycles the viability of the composed beads was observed through SEM/EDS, UV-DRS and FT-IR analysis, which further justified its use industrially. Estimation of nitrate, nitrite, and ammonia as its by-products was performed for the confirmation of mineralization. Generation of the intermediate products was also identified through GC-MS analysis, and a degradation pathway was proposed. Toxicity test confirming the nontoxic nature of the treated solution was performed on
E. coli
grown in Miller’s Luria Bertani Broth nutrient medium.
Scarcity of high-cost silica sand, casting defect such as hot tear in hard moulds and casting ejection problem after solidification are the key industrial problems. Sawdust is a by-product of wood ...working industries, and economic disposal of sawdust in these industries is a growing concern to the wood industries. The present work utilized sawdust as an additive in preparing mould cavity for casting applications. Sand mould properties such as compression strength (CS), mould hardness (MH), gas evolution (GE), permeability (P) and collapsibility (CP) will have good impact on the quality of castings. The effect of variables, namely quantity of resin, hardener, sawdust and setting time, on no-bake furan-bonded sand system is studied in the present research work. The experiments are conducted as per design of experiments, and the data are used to investigate the effect of individual and combined parametric contributions towards responses and establish nonlinear input–output relationships. All nonlinear regression models (that is, input–output relationships) are found to be statistically adequate. The input–output relations are analysed and presented for each of the response with the help of surface plots. Further, the models are found to predict the output close to the experiment (target value). The grand average value in predicting responses is found to be equal to 5.03%. The multi-objective optimization of responses with conflicting nature (minimize: GE and CP; maximize: CS, P and MH) is carried out with the help of global fitness function values determined using genetic algorithm, particle swarm optimization, teacher–learner-based optimization and JAYA algorithms. The optimized values of process parameters that resulted in best set of responses are found to be equal to 60 min, 2.01%, 0.6% and 0.93% for setting time, quantity of resin, hardener and sawdust, respectively. Two automobile coupling parts are cast by pouring molten aluminium into the mould cavity with the optimized and non-optimum sand mould conditions. Further, these two cast components are tested for their quality characteristics, such as surface finish, yield strength, hardness, density and secondary dendrite arm spacing. It has been observed that the quality characteristics of castings produced in mould with optimized parameters are found to be much better.
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