Abstract
Sand casting is used to create a wide range of parts, from small, intricate components to large, heavy-duty industrial parts. Prototypes, custom parts, and small to medium production runs are especially well suited for this technique. By removing the remaining binder from the sand particles, the thermal reclamation technique allows the sand to be returned to its original state, typically of a higher quality than fresh sand. Research indicates that the cost savings by thermal reclamation can reach fifty percent when compared to the purchase and disposal of new sand. Due to environmental regulations, sand disposal has emerged as a critical issue for foundries. Foundries are under pressure to enhance and maintain casting quality while decreasing their negative environment effects. In addition to internal pressure, foundries are encouraged to implement recycling and reuse practices under the United Nations Sustainable Development Goals. This study looks at the thermal reclamation of waste sand produced during rapid sand casting based on these factors.
The Voxeljet VX 1000 printer's waste furan-bonded sand, which was gathered from the Vaal University of Technology, was used in this investigation. Prior to being mechanically tested, the sands were first characterized as received, thereafter thermally reclaimed using the tube furnace and the muffle furnace techniques. The American Foundry Society grain fineness number (AFS GFN) of 87.79 indicated that virgin silica sand was finer than both Used Sand 1 and Used Sand 2. At 80.35 and 68.05, respectively, two batches of used sand known as Used Sand 1 and Used Sand 2 both had much lower AFS GFN than virgin sand. Due to the greater AFS of Used sand 1 and Virgin silica sand, a superior surface quality with reduced permeability was predicted while making cores. It was found that the virgin silica sand had a pH of 2.86 when it was received, which suggests the presence of sulphonic acid. The pH values of Used Sand 1 and Used Sand 2 were 3.03 and 3.29, respectively, indicating the use of sulphonic acid.
Upon thermal reclamation the pH values increased with the rate of temperature increases during the muffle furnace process, and during the tube furnace process with results of 3.67 for Used sand 1 and 3.98 for Used sand 2 both at temperature of 600⁰C for 10 minutes.