Ordinary coated sand: its composition is generally composed of quartz sand thermoplastic phenolic resin, and calcium stearate constitute urotropine coated sand regeneration, without concerning additives. The resin was added in an amount typically at a certain strength requirements are relatively high renewable coated sand production line, do not have high temperature, low inflation, low gas and other characteristics, applies to some less demanding, simpler structure of cast iron production. High-strength low gas coated sand: on the basis of the common-coated sand by adding related properties "additive" and the introduction of new preparation process, so a substantial decline in the amount of resin significantly reduces gas evolution, and can delay gas - speed. The coated sand with high strength, low inflation, low gas, slow gas evolution and other characteristics, especially suitable for cast iron, steel castings requirements of small and medium hair volume low sand core, such as sand and other core body coated sand ( coated sand). Before molding sand surface that is covered with a layer of solid resin film is sand or core sand. There are two methods of cold and hot coating process: Cold method using the resin is dissolved in ethanol, and adding hexamine in the sand process, so that the surface of both coated sand coated sand recycling equipment manufacturers, volatile ethanol, was coated sand; thermal preheating the sand to a certain temperature, add the resin melted, stirring the resin coated sand surface, plus methenamine solution and lubricants, cooling, crushing, screening was coated sand . For steel castings, coated sand will review indicators iron castings 1992 Revision coated sand industry standards set forth: room temperature flexural strength, thermal bending strength, loss on ignition, particle size and melting point. Optional detection indicators are: room temperature tensile strength, tensile strength hot, gas evolution and mobility. Performance coated sand for nearly 10 years has been greatly improved, a corresponding increase in the number of new detection indicators: (1) high temperature compressive strength - to simulate actual conditions of casting, coated sand core test at the time of 1000-1500 ℃ compressive strength. (2) Heat time - test coated sand core at a high temperature (700-1500 ℃) to maintain strength, no distortion, no collapsing of time. (3) anti-Shelling - The test coated sand against shelling capacity. Coated sand regeneration, Qingdao Heng (certified), coated sand regeneration by Qingdao Heng Machinery Co. Qingdao Heng Machinery Co., Ltd. (www.thjidian.com) is in Qingdao, Shandong Cleaning equipment leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Qingdao Heng leadership with the staff warmly welcome all inquiries negotiations to create a better future Qingdao Heng.