Preparation method of residue-free high-concentration water reducer

Abstract

The invention relates to a preparation method of a residue-free high-concentration water reducer, which is characterized by comprising the steps of injecting 1200kg industrial naphthalene into a reaction kettle, heating to 135 DEG C with steam, adding 1150 kg of concentrated sulfuric acid, heating to 170 DEG C, performing heat preservation for 150min, injecting cold water into a jacket to cool to 110 DEG C after heat preservation, opening a manhole to add 265 kg of citric acid, putting a cover in place, reacting for 30min at the temperature, cooling to 95 DEG C, opening a methanal valve, slowly adding 720kg of 37% methanol at the temperature of 90-100 DEG C, raising the temperature to 105-115 DEG C after the addition, rapidly injecting 1000 kg of warm water at the temperature of about 50 DEG C when current of a stirrer rises by 10A, stirring for 30min, putting in a neutralization kettle, neutralizing with 35% sodium hydroxide till a PH (potential of hydrogen) value is 7-9, and putting a material in a drying tower for drying to obtain a finished product. The method has the benefits that a yield is increased, and the produced water reducer exerts an action of reducing slump of concrete in the fresh concrete to achieve the purpose of pumping.

Description

technical field [0001] The invention relates to a naphthalene-based water reducer mainly used in commercial concrete and pumped concrete to reduce the water consumption of concrete mixing, increase the fluidity of freshly mixed concrete, thereby improve the strength of concrete, and change the pumpability of pumped concrete. Agent industry, specifically, a method for preparing a waste-free high-concentration water reducer. Background technique [0002] The current main raw materials for the production of high-concentration naphthalene-based water reducers are industrial naphthalene, concentrated sulfuric acid, formaldehyde, sodium hydroxide, lime water, etc. The main reaction principle is as follows: [0003] 1. Vulcanization reaction: naphthalene + sulfuric acid → (150°C) β naphthalenesulfonic acid, [0004] Side reaction: naphthalene+sulfuric acid→αnaphthalenesulfonic acid; [0005] 2. Hydrolysis reaction: α naphthalenesulfonic acid + water → (110°C) naphthalene + sulfur...

AI Technical Summary

Problems solved by technology

The calcium sulfate generated in the neutralization reaction is a precipitate. If only sodium hydroxide is used to neutralize, the sodium sulfate generated in the product can reach 20%, and the obtained product is a low-concentration water reducer. If a small amount of sodium hydroxide is used to neutralize, If neutralized with lime water, the obtained sodium sulfate content is only less than 10%. This product is a high-concentration water reducer. The price difference between the two is about 1,500 yuan, but a large amount of calcium sulfate precipitates will be generated in this way. Use a centrifuge or vacuum filter to remove the waste and fill it up. This separation process is very complicated, the process takes a long time, and the labor intensity is high. At the same time, a large amount of waste residue is generated, polluting the environment, and the energy consumption is also high. The product also contains a lot of precipitates that cannot be separated.