Technique for producing sulfonic acid firming agent for foundry by industry waste material-sulfonic acid mother liquor

Abstract

The invention discloses a process for preparing a sulfonic acid curing agent for casting from industrial waste, i.e. sulfonic acid mother liquor, which comprises the following steps of: pre-treating the sulfonic acid mother liquor, adding 98% concentrated sulfuric acid 175 to 250 parts in dimethylbenzene 100 parts, stirring, heating to 110 to 140 DEG C, keeping the temperature and reacting for 1 to 3 h, decreasing the temperature below 70 DEG C, adding water and alcohol solvent 40 to 105 parts slowly, adding the pre-treated sulfonic acid mother liquor 70 to 350 parts, stirring for 0.5 to 1 h, decreasing the temperature below 40 DEG C, adding hydrogen peroxide 2 to 3 per mill, and stirring uniformly to obtain the final product. The sulfonic acid curing agent prepared by the process keeps the excellent performance of original curing agent, and is improved in the selection of use range, cured strength, viscosity, odor, decrease of production cost, etc. by different degrees. Particularly, the sulfonic acid curing agent has very strong competition advantages in environment protection, low viscosity and low cost.

Description

technical field [0001] The invention relates to a process for producing a sulfonic acid curing agent for casting by using industrial waste-sulfonic acid mother liquor. Background technique [0002] With the rapid development of China's foundry industry, domestic foundry companies are gradually connecting with foreign foundry industries. In recent years, the development of resin sand for foundry, especially no-hardening furan resin for foundry, has been particularly rapid. At present, the amount of furan resin used in China is One million tons per year, and there is still a trend of rapid increase year by year, and the annual usage of sulfonic acid curing agent is also about one million tons. The current production process of the sulfonic acid curing agent is as follows: xylene and sulfuric acid are mixed in a mass ratio of 1:1.75-2.2 at a temperature of 105-130°C for 6-7 hours, and alcohol is added in proportion after the reaction. Solvents (methanol and ethanol, etc.), sti...

AI Technical Summary

Problems solved by technology

However, the sulfonic acid curing agent produced by the current production process has the following disadvantages: 1. The price of chemical materials has risen sharply, and the price of xylene is currently 8,000-10,000 yuan / ton, resulting in a sharp increase in production costs; 2. Due to the use of Xylene is produced, so the existence of free xylene in the finished product causes some irritating gas volatilization in the process of casting (molding core making and pouring), which affects the working environment of production; 3. Due to the use of 98 in the production process %concentrated sulfuric acid or 105% oleum is not easy to control the reaction speed in the production process, it will corrode the equipment and cause great harm to the working environment of the workshop, etc.

4. The production time of sulfonic acid curing agent using this process is long, the yield and output are too low, etc.

[0004] Sulfonic acid mother liquor is a by-product (industrial waste) of industrial production of p-toluenesulfonic acid, xylenesulfonic acid and p-cresol. This waste is currently harmful to the environment and the degree of pollution is large, and the energy consumption required in the industrial process is large. , high cost, if not handled properly, it will bring great harm to our environment and life, and cause serious pollution to society and the environment

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