Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India.
Department of Earth Science, Indian Institute of Technology Bombay, Mumbai, 400076, India.
J Environ Manage. 2021 Feb 1;279:111628. doi: 10.1016/j.jenvman.2020.111628. Epub 2020 Nov 14.
Binder material (e.g. bentonite, polymeric resins) is used for producing molds and cores in foundries. It deactivates upon exposure to the high temperature (~1400C) of molten metal. As a result, these binders form either loosely or strongly bound deposits on the surface of sand grains, leaving them unsuitable for further use. Disposal of Waste Foundry Sand (WFS) remains to be one of the significant challenges faced by foundry industry nowadays. In order to remove these deposits from WFS, we have studied and compared two types of methods namely, mechanical and thermal reclamation. The WFS samples after being reclaimed either mechanically or thermally or by combination of both, are compared using various tests. These tests include determination of loosely bound and strongly bound clay content, compressive strength, Grain Fineness Number (GFN), Loss on Ignition (LOI), Acid Demand Value (ADV), Particle size distribution and optical microscopy. We have used the aforementioned tests to characterize the quality of foundry sand and the suitability of reclaimed sand for use in mold and core production in foundries. The results showed that neither of these treatments is sufficient to completely remove the deposits from sand grains. However, solely mechanically reclaimed sand is suitable for the mold production after maintaining 8% active clay and 10% loosely bound clay in the reclaimed sand, respectively.
黏结剂材料（例如膨润土、聚合树脂）用于铸造厂生产模具和型芯。它在接触到熔融金属的高温（~1400°C）时会失活。结果，这些黏结剂在砂粒表面形成松散或紧密结合的沉积物，使其不适合进一步使用。废铸造砂（WFS）的处理仍然是当今铸造行业面临的重大挑战之一。为了从 WFS 中去除这些沉积物，我们研究并比较了两种类型的方法，即机械和热回收。经过机械或热或两者结合回收的 WFS 样品，使用各种测试进行比较。这些测试包括测定松散结合和强结合的粘土含量、抗压强度、颗粒细度数（GFN）、灼烧损失（LOI）、酸需求值（ADV）、粒度分布和光学显微镜。我们使用上述测试来表征铸造砂的质量和回收砂在铸造厂中用于模具和型芯生产的适用性。结果表明，这些处理方法都不足以将沉积物从砂粒中完全去除。然而，仅经过机械回收的砂在分别保持回收砂中 8%的活性粘土和 10%的松散结合粘土的情况下，适用于模具生产。
