Method for recycling waste foundry sand through compound roasting device

Abstract

The invention discloses a method for recycling waste foundry sand through a compound roasting device. The method for recycling the waste foundry sand through the compound roasting device comprises thefollowing steps that S1, materials enter a receiving tank through a material uniformizing plate, then enter a feeding protection device through an impeller and finally enter a horizontal combustion chamber; S2, the materials are blown and boiled through hot air from the bottom of the combustion chamber to flow from one end of the combustion chamber to the other end of the combustion chamber, andthree-stage roasting is conducted in the flowing process of the materials, wherein the temperature for the first stage of roasting is 300-400 DEG C, and the time for the first stage of roasting is 10-20 s; the temperature for the second stage of roasting is 600-800 DEG C, and the time for the second stage of roasting is 180-240 s; and the temperature for the third stage of roasting is 850-900 DEGC, and the time for the third stage of roasting is 10-20s; and S3, the roasted materials enter an air preheating chamber, exchange heat with cold air to be cooled to 200-300 DEG C and then are discharged, and high-temperature waste gas is exhausted after heat exchange. According to the method for recycling the waste foundry sand through the compound roasting device, the discharge temperature is lower than 300 DEG C, and the furnace temperature can be increased rapidly and can be increased to the material roasting temperature within 30 min; and the exhausted waste gas has a low temperature andcontains few hazardous substances.

Description

technical field [0001] The invention belongs to the technical field of material roasting, and in particular relates to a method for recycling foundry waste sand based on compound roasting equipment. Background technique [0002] About 90% of the castings in the foundry industry are produced by sand casting. The basic raw materials for making sand molds are foundry sand and sand binders. The commonly used sand binders can be divided into organic types (such as: phenolic resin, cold box resin, etc.) and inorganic types (such as: 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 foundry waste sand, a large amount of silica sand comes from nature, the scale development of the foundry industry will inevitably lead to natural silica sand resources A large number of mining and discarding of a large amount of waste sand containing harmful substances. For the sustai...

AI Technical Summary

Problems solved by technology

The existing thermal regeneration method is insufficient for the combustion of foundry waste sand and waste gas, resulting in a large amount of waste gas emissions, poor environmental protection effect, and relatively high heat loss

The main reason is that the feeding method of the vertical roasting furnace is from top to bottom, and the combustion chamber is at the bottom. During the feeding process, the casting waste sand is heated, but the temperature of combustion cannot be reached, and the organic matter sticking to the casting waste sand is volatilized and discharged. , and the exhaust gas is directly discharged outside without heat exchange, resulting in large heat loss, high sand production temperature, and high energy consumption

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