Method for recovering polyether from waste metal processing liquid and application of polyether in concrete slump retaining agent

Abstract

The invention discloses a method for recovering polyether from waste metal processing liquid and application of the polyether in concrete slump retaining agent. The method for recovering the polyether from the waste metal processing liquid comprises the following steps: adding inorganic base to water-based waste metal processing liquid containing the polyether to adjust the pH value of the waste metal processing liquid to 10-12, standing the waste metal processing liquid for reaction, filtering, adding activated carbon and an inorganic acid to adjust the pH value of the waste metal processing liquid, heating to the temperature above the cloud point temperature, layering solution, standing at constant temperature, taking polyether phase on the upper layer, adding anti-oxidant to the polyether phase, and fully drying to remove water until the water content is 0.05 percent by weight or less to obtain the reaction product which is polyether. The following raw materials are needed when the polyether is applied to the concrete slump retaining agent: a catalyst, maleic anhydride, water, sulfonated styrene and an initiator in addition to the polyether. The polyether and the maleic anhydride are directly subjected to the esterification reaction under the heating condition without adding organic solvent and water and adopting a condensing and refluxing device, thus the equipment requirement and the production cost are reduced, and the production safety is improved. The prepared concrete slump retaining agent has good slump retaining performance, high water reducing rate and good compatibility with cement.

Description

[0001] technical field [0002] The invention relates to a technology for recovering polyether from water-based metal processing fluid and its application in the preparation of environment-friendly high-performance concrete slump-retaining agent. Background technique [0003] The application of water-based metalworking fluids has been very popular. Water-soluble polyether is an important component of many water-based metalworking fluids. Compared with general water-soluble oily agents, especially fatty acid soaps, it has better cooling, stability, Antibacterial, hard water resistance and defoaming properties, it has good extreme pressure, and has a significant synergistic effect with fatty acids or phosphates, and has a long service life, no obvious harm to the human body, and low physiological and ecological toxicity , does not cause corrosion to metals, and is widely used in metal processing. There are three main types of water-based metalworking fluids: emulsion, micro...

AI Technical Summary

Problems solved by technology

The evaporation method is to heat water to boiling, and then condense the water vapor to discharge waste water that meets the discharge regulations. It does not need to be sent to a public treatment plant for treatment. The main advantage is that the indicators after treatment are excellent, and all kinds of waste liquids can meet the discharge standards after treatment. The process is simple. It is easy to operate, but its disadvantages are high energy consumption (converting liquid water into water vapor requires a lot of energy), poor safety, possible fire and explosion, most of them require an air pollution discharge permit, and the gas has corrosion or unpleasant smell (especially waste liquid When there are sulfides in the medium), a larger space is required

The application of chemical method is more common than other treatment methods. It is suitable for both large and small amounts. It also includes two methods: inorganic salt separation (acid-aluminum method) and polymer (cationic surfactant) separation. These methods are based on surface tension In essence, the flocculation of aluminum hydroxide and polymer is used to separate the changes of pH value and pH value. The price of this method is moderate and it is conducive to medium and large-scale treatment. Unable to achieve polyether recycling

Membrane separation is divided into three methods: microporous filtration, ultrafiltration and reverse osmosis. The most commonly used method is ultrafiltration membrane treatment, which generally requires heating and vacuuming, which requires high equipment requirements and a large one-time investment. It is difficult to fully promote and apply it.

Chinese patent applications No. 200710117665.0 and No. 2006l0058747.8 provide a method for processing and recycling monocrystalline silicon cutting waste liquid. Silicon carbide particles and polyethylene glycol solution are recycled in silicon cutting process, but the purification and separation of polyethylene glycol has not been realized

Chinese patent application No. 2006l0029378.X provides a method for recovery and treatment of monocrystalline silicon cutting waste liquid. The acidified waste liquid is sprayed and dehydrated to obtain polyethylene glycol ether, but the composition of water-based metalworking fluid is lower than that of monocrystalline silicon cutting fluid. It is complex and contains extreme pressure agent and other components, which cannot effectively separate the extreme pressure agent and polyethylene glycol ether components, which is not conducive to the production and preparation of concrete slump retaining agent in the next step

Chinese patent No. 0382609.9 provides a method for separating and recovering polyethylene glycol (PEG) in an aqueous two-phase system (ATPS), mainly using microwave energy to recover PEG from the used aqueous two-phase system, which requires special microwave equipment. The investment cost of disposable equipment is high, production and maintenance are difficult, and it is difficult to apply on a large scale

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