阅读说明：本技术 低游离硫酸铸造固化剂的制备 (Preparation of low free sulfuric acid casting curing agent ) 是由 王世汉 于 2018-07-25 设计创作，主要内容包括：低游离硫酸铸造固化剂的制备,其特别原料重量配比(千克)：甲苯40-45、二甲苯120-180、98%硫酸1100-1500、甲醇400-540、自来水100-300、双氧水10-12。特别配制方法：投甲苯40-45千克,再投二甲苯120-180千克,升温到40-45度,滴加98%硫酸1100-1500千克,升温至110摄氏度-115摄氏度反应一小时,降温60摄氏度以下,滴加甲醇400-540千克,滴加过程不超过60摄氏度,加完后,在50-60摄氏度中反应40分钟,降温至50摄氏度以下,根据需要的酸度加入自来水100-300千克,同时加入双氧水10-12千克,搅拌10分钟放料；其有益效果是：解决了常规树脂砂生产过程中固化剂游离硫酸偏高的问题,提高了树脂强度,减少了在浇铸时产生的过大发气量,提高了铸件质量。(The preparation of the low free sulfuric acid casting curing agent comprises the following special raw materials in parts by weight (kilogram): 40-45 parts of toluene, 120 parts of xylene, 180 parts of 98 percent sulfuric acid, 1100 parts of 1500 parts of methanol, 400 parts of 540 parts of tap water, 100 parts of 300 parts of tap water and 10-12 parts of hydrogen peroxide. The special preparation method comprises the following steps: 40-45 kg of toluene is added, 180 kg of dimethylbenzene is added, the temperature is raised to 40-45 ℃, 1500 kg of 98 percent sulfuric acid 1100-plus is dripped, the temperature is raised to 110-115 ℃ for reaction for one hour, the temperature is lowered to below 60 ℃, 540 kg of methanol-plus is dripped, the dripping process does not exceed 60 ℃, after the dripping is finished, the reaction is carried out for 40 minutes at 50-60 ℃, the temperature is lowered to below 50 ℃, 300 kg of tap water 100-plus is added according to the required acidity, and simultaneously 10-12 kg of hydrogen peroxide is added, and the materials are stirred for 10 minutes for emptying; the beneficial effects are as follows: the problem of curing agent free sulfuric acid in the production process of conventional resin sand is high is solved, the resin strength is improved, the excessive gas evolution generated in the casting process is reduced, and the casting quality is improved.)

1. Preparation of the low free sulfuric acid casting curing agent:

the weight ratio of the special raw materials is as follows: kilogram (kilogram)

40-45 parts of toluene

Xylene 120-

98% sulfuric acid 1100-

Methanol 400-

Tap water 100-

10-12 parts of hydrogen peroxide

The preparation method comprises the following steps:

40-45 kg of toluene is added, 180 kg of dimethylbenzene is added, the temperature is raised to 40-45 ℃, 1500 kg of 98 percent sulfuric acid 1100-plus is dripped, the temperature is raised to 110-115 ℃ for reaction for one hour, the temperature is lowered to below 60 ℃, 540 kg of methanol-plus is dripped, the dripping process does not exceed 60 ℃, after the dripping is finished, the reaction is carried out for 40 minutes at 50-60 ℃, the temperature is lowered to below 50 ℃, 300 kg of tap water 100-plus is added according to the required acidity, and simultaneously 10-12 kg of hydrogen peroxide is added, and the materials are stirred for 10 minutes for emptying.

Technical Field

The invention relates to the field of chemical industry, in particular to preparation of a low free sulfuric acid casting curing agent.

Background

The known casting resin is a main molding material in the casting industry, the raw material of the casting resin is from agricultural and sideline products, the regeneration is realized, the expected future market development prospect is good, but the curing agent of the matched product of the resin has high free sulfuric acid content, and excessive gas evolution and sulfide are generated during high-temperature casting of molten iron, so that the casting quality is seriously influenced.

The invention patent of 2010 (casting resin with low residual methanol and preparation thereof) is published (patent number: 2010102332874), the quality effect is good, although the content of formaldehyde is reduced from 0.3% to 0.1%, the problem of overlarge pungent smell is solved, the environment is improved, but the defect of overlarge gas evolution caused by higher free sulfuric acid of a curing agent is overcome, and no good technical scheme is provided so far.

Disclosure of Invention

Through years of research and practice, the applicant invents the preparation of the low free sulfuric acid casting curing agent, improves the strength and toughness of resin, solves the problem that the curing agent free sulfuric acid is higher in content and excessively large in gas evolution in the conventional resin sand production process, and improves the quality of castings; the new curing agent formula process not only reduces the production cost of the curing agent, but also mainly reduces the problem of higher free sulfuric acid, so that the free sulfuric acid of the curing agent is reduced by more than 30 percent under the condition of the same acidity compared with the common curing agent, the excessive gas evolution generated during casting is effectively reduced, and meanwhile, under the condition that the resin is not changed, the strength of the resin can be improved by 1.5-2.5 kilograms and the strength and the toughness of the resin are improved by adding the curing agent compared with the common curing agent.

In order to achieve the above object, the preparation of the low free sulfuric acid casting curing agent of the present invention is achieved by:

the weight ratio of the raw materials is as follows: kilogram (kilogram)

40-45 parts of toluene

Xylene 120-

98% sulfuric acid 1100-

Methanol 400-

Tap water 100-

10-12 parts of hydrogen peroxide

The special preparation method comprises the following steps: 40-45 kg of toluene is added, 180 kg of dimethylbenzene is added, the temperature is raised to 40-45 ℃, 1500 kg of 98 percent sulfuric acid 1100-plus is dripped, the temperature is raised to 110-115 ℃ for reaction for one hour, the temperature is lowered to below 60 ℃, 540 kg of methanol-plus is dripped, the dripping process does not exceed 60 ℃, after the dripping is finished, the reaction is carried out for 40 minutes at 50-60 ℃, the temperature is lowered to below 50 ℃, 300 kg of tap water 100-plus is added according to the required acidity, and simultaneously 10-12 kg of hydrogen peroxide is added, and the materials are stirred for 10 minutes for emptying.

The invention has the beneficial effects that: the problem of curing agent free sulfuric acid in the production process of conventional resin sand is high is solved, the resin strength is improved, the excessive gas evolution generated in the casting process is reduced, and the casting quality is improved.

The present invention will be described in further detail with reference to the following drawings and specific examples.

Drawings

FIG. 1 is a flow chart of the process for preparing the low free sulfuric acid casting curing agent of the present invention.

Detailed Description

The preparation of the low free sulfuric acid foundry hardeners of the present invention is described in further detail below with reference to the accompanying drawings and specific examples, but the invention is not limited to the following examples.

The weight ratio of the raw materials is as follows: kilogram (kilogram)

40-45 parts of toluene

Xylene 120-

98% sulfuric acid 1100-

Methanol 400-

Tap water 100-

10-12 parts of hydrogen peroxide

The special preparation method comprises the following steps: 40-45 kg of toluene is added, 180 kg of dimethylbenzene is added, the temperature is raised to 40-45 ℃, 1500 kg of 98 percent sulfuric acid 1100-plus is dripped, the temperature is raised to 110-115 ℃ for reaction for one hour, the temperature is lowered to below 60 ℃, 540 kg of methanol-plus is dripped, the dripping process does not exceed 60 ℃, after the dripping is finished, the reaction is carried out for 40 minutes at 50-60 ℃, the temperature is lowered to below 50 ℃, 300 kg of tap water 100-plus is added according to the required acidity, and simultaneously 10-12 kg of hydrogen peroxide is added, and the materials are stirred for 10 minutes for emptying.

The acidity of the curing agent in the technology is flexibly increased and decreased by the technicians in the field according to the needs.