Method for recycling foundry waste sand based on vertical energy-saving roasting furnace

Abstract

According to the method for recycling the foundry waste sand based on the vertical energy-saving roasting furnace, hot-method regeneration and wet-method mechanical regeneration are combined, and meanwhile, an abrasive material is added into the waste sand during hot roasting, so that a certain grinding effect is achieved; chemical dissolution, burning and friction effects are combined together to achieve the effect of well removing surface resin and inorganic impurities of the mixed casting waste sand, and the recovery rate is high. The method further optimizes the heat cycle during roasting, and is energy-saving, environment-friendly and efficient. A novel vertical energy-saving roasting furnace is adopted in the roasting process, a unique secondary roasting technology is adopted, tail gas and materials are subjected to secondary roasting, waste heat can be efficiently utilized through secondary roasting, energy consumption is low, the quality of produced regenerated sand is excellent and uniform, and the waste sand regeneration and reuse effect is remarkable.

Description

technical field [0001] The invention belongs to the technical field of foundry sand recycling, and in particular relates to a method for recycling waste foundry sand based on a vertical energy-saving roasting furnace. Background technique [0002] About 90% of the castings in the foundry industry are produced by the sand casting process. Steel, iron and most non-ferrous alloy castings can be obtained by sand casting. The basic raw materials for making sand molds are foundry sand and molding sand binders. Commonly used molding sand binders can be divided into organic types (for example: phenolic resin, cold box resin, etc.) and inorganic types (for example: clay, water glass, etc. ), and the commonly used foundry sand is silica sand (20-140 mesh particles), generally producing 1 ton of castings will produce 1-1.5 tons of waste foundry sand, a large amount of silica sand comes from nature, the scale development of the foundry industry will inevitably lead to natural silica san...

AI Technical Summary

Problems solved by technology

[0003] Although there are many types of waste sand regeneration methods nowadays, there are many problems in these methods. The removal rate of impurity film by dry mechanical regeneration is not more than 80%. The particle size of regenerated sand is getting smaller and smaller. On the one hand, the recovery rate of regenerated sand is greatly reduced (not exceeding 80%). The surface of the reclaimed sand obtained will have cracks, and the acid consumption of regenerated sand is high, which cannot meet the technical quality requirements of foundry sand. On the other hand, a large amount of fine powder is produced, and the technical pressure for secondary treatment and utilization is relatively high; the thermal regeneration method has a good removal effect on flammable organic impurity films such as phenolic resin and cold box resin, but it is not effective for clay, water, etc. The removal effect of inorganic impurity films such as glass is not good; and the tail gas after roasting needs to be purified; the wet mechanical regeneration method has a good removal effect on clay, water glass and other water-soluble inorganic impurity films, but for phenolic resin, The removal effect of organic impurity films such as cold box resin is not good; and the subsequent sand, water, and impurities need to be further separated, and even the sewage generated in the production process needs to be treated for water

[0004] In summary, the existing technologies are all aimed at recycling a single type of waste sand, and there are few studies on the regeneration technology of mixed casting waste sand

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