Production of ceramic materials using waste foundry sand and marble powder

Approximately 1 million tons of waste foundry sand (WFS), which is formed as a result of production in the casting sector, which is one of the sectors that are important for our country, needs to be reused. In recent years, many scientific studies have been carried out on this subject. As a result of this research, it was ensured that the waste foundry sand was reused together with auxiliary additives in sectors such as ceramics, construction, and highway. While the contribution of the foundry industry to the country's economy is considered a positive value, the limited waste foundry sand storage areas and the damages it may cause to the environment are negative. In addition, the sector is growing every year. In this study, cement from the inorganic binder family and various amounts of marble powder, namely 5%, 10%, 15%, and 20% were added to 50 g of waste foundry sand and ground in a ring mill, and ceramic mixtures were obtained. The mixtures obtained after this process were poured into a 12-section silicone plastic mold with 25x25 dimensions and 3 cm depth and shaped. The samples were divided into two groups namely unsintered and sintered (9 hours at 800°C) by producing 3 pieces of each class. The characterization of the obtained ceramic mixtures was carried out in the laboratory by SEM, compression test, and Archimedean density tests. While the average compressive strength of the unsintered samples was 5.21 MPa in the 0% MP-containing sample, it decreased to 4.08 MPa in the 20% marble powder containing one. In terms of density, while the water absorption value was 13,7191% in 0% MP sample, it was 16,6760% in 5% sample, and it further increased gradually and became 18,6054% in other samples. The apparent solid density was 2.3860 gr/cm3 in 5% marble powder sample and 2.7023 gr/cm3 in 20% MP-containing sample. In the sintered samples, while 0% MP added samples did not exhibit any change in surface appearance and in mass, variation in the surface appearance and massive cracks and dispersions occurred in the samples containing MP additives. Compression test of these samples was performed on those with 0% MP containing sample and the average compressive strength was found to be 1.37MPa. Increasing the ratio of MP additive in waste foundry sand (WFS) led to an increase in density. In parallel with this, the compressive strength decreased with increasing MP.