阅读说明：本技术 一种增强型硫氧镁水泥缓凝剂 (Enhanced magnesium oxysulfate cement retarder ) 是由 刘晓莉 吴潇潇 岂珊珊 杨宇飞 杨红健 于 2019-03-29 设计创作，主要内容包括：本发明公开了一种增强型硫氧镁水泥缓凝剂,所述硫氧镁水泥缓凝剂包括以下组分及其重量份：葡萄糖酸0.1～3份,葡萄糖酸钠0.1～0.5份,丙二酸类0.1～0.5份,丁二酸0.1～0.5份。其能用于改善硫氧镁水泥性能,提高硫氧镁水泥强度并延长硫氧镁水泥的凝结时间。经测定,在25～40℃的条件下,添加增强型缓凝剂后硫氧镁水泥的初凝时间延长了296％以上,终凝时间延长了256％以上,28抗折强度可达30.5MPa以上,增加了软化系数高至0.9,早期强度均得到显著提高。且本发明的增强型缓凝剂廉价易得,酸性较弱,便于储存,满足夏季硫氧镁制品所用缓凝剂要求。(The invention discloses an enhanced magnesium oxysulfate cement retarder, which comprises the following components in parts by weight: 0.1-3 parts of gluconic acid, 0.1-0.5 part of sodium gluconate, 0.1-0.5 part of malonic acid and 0.1-0.5 part of succinic acid. It can be used to improve the performance of magnesium oxysulfate cement, increase the strength of magnesium oxysulfate cement and prolong the setting time of magnesium oxysulfate cement. According to the determination, under the condition of 25-40 ℃, the initial setting time of the magnesium oxysulfate cement is prolonged by more than 296%, the final setting time is prolonged by more than 256%, the 28 flexural strength can reach more than 30.5MPa, the softening coefficient is increased to 0.9, and the early strength is obviously improved. The enhanced retarder is cheap and easy to obtain, has weak acidity, is convenient to store, and meets the requirements of retarders used for magnesium oxysulfate products in summer.)

1. The enhanced magnesium oxysulfate cement retarder is characterized by being prepared from the following raw materials in parts by weight: 0.1-3 parts of gluconic acid, 0.1-0.5 part of sodium gluconate, 0.1-0.5 part of malonic acid and 0.1-0.5 part of succinic acid.

2. An enhanced magnesium oxysulfate cement retarder according to claim 1, wherein the malonic acid species comprises one or more mixtures of malonic acid, sodium malonate, and calcium malonate.

Technical Field

The invention relates to the technical field of cement additives, in particular to an enhanced magnesium oxysulfate cement retarder.

Background

The magnesium oxysulfate cement is an air-hardening cementing material formed by fully hydrating light-burned magnesium oxide and magnesium sulfate aqueous solution, has the advantages of quick setting, early strength, fire resistance, flame retardance, wear resistance, corrosion resistance, no halogen return, low corrosion to reinforcing steel bars and the like, and is mainly used for assembled buildings, heat-insulating wallboards, wood substitute materials, fireproof products, artware and the like. At present, magnesium oxysulfate cement is generally considered to be an upgraded and updated product of magnesium oxychloride cement, but compared with magnesium oxychloride cement, the magnesium oxysulfate cement has poor mechanical properties, so that the wide application of the magnesium oxysulfate cement is limited, and the defect is improved mainly by adding a modifier at present.

It is known that in hot summer, the setting time of the magnesium cement slurry is shortened due to the characteristics of higher temperature and production process of enterprises, so that the injection molding is difficult, the bubbles of the slurry are increased, and the compactness of the product is reduced. The inside of cement is easy to generate temperature stress due to hydration heat release, so that cracks are generated in the product, and finally the quality of the product is reduced. Therefore, in summer production, the retarder needs to be added to delay the hydration of the slurry, improve the workability of the slurry, reduce the construction difficulty and improve the product quality.

At present, the research on the retarder of the ordinary portland cement is basically mature, a plurality of literatures and patents are systematically summarized, for example, in the literature, "the action mechanism of the retarder and the influence on the performance of the cement concrete", the retarder suitable for the cement concrete is classified, the effects and the action mechanisms of various retarders are described in detail, but the research on the retarder suitable for a magnesium oxysulfate cement system is lacked, the research stage of the reinforcing agent is remained, and the existing modifier or retarder has single function and is deficient in the performance improvement of the magnesium oxysulfate cement.

The commonly used modifier is citric acid, and the document "citric acid modification effect on magnesium oxysulfate cement" discloses the influence of citric acid on the mechanical property and the setting time of magnesium oxysulfate cement, but the strength improvement and the extension degree of the setting time of the singly doped citric acid are limited, and the production requirement cannot be met.

Disclosure of Invention

Aiming at the problems, the invention provides an enhanced retarder, and aims to prolong the setting time of magnesium oxysulfate cement and improve the flexural strength of the magnesium oxysulfate cement by adding the enhanced retarder. The gluconic acid, the sodium gluconate, the malonic acid and the succinic acid adsorb magnesium oxide particles in a magnesium oxysulfate cement system, so that the hydration of the magnesium oxide particles is delayed, the hydration process of the system is changed, and the system is induced to generate a large amount of 517(5Mg (OH) 2. MgSO 4. 7H2O) needle crystal phases, so that the coagulation time of the magnesium oxysulfate cement is delayed, the strength of the magnesium oxysulfate cement is improved, the hydration heat of the cement is reduced, the generation of microcracks in the product is reduced, and the problems of difficult injection molding and low strength of the product in summer production are solved. In addition, each component of the retarder is industrial grade, is cheap and easy to obtain, has low mixing amount and obvious cost advantage, is weak in acidity and is convenient to store.

An enhanced magnesium oxysulfate cement retarder is prepared from the following raw materials in parts by weight: 0.1-3 parts of gluconic acid, 0.1-0.5 part of sodium gluconate, 0.1-0.5 part of malonic acid and 0.1-0.5 part of succinic acid.

Further, the malonic acid comprises one or more of malonic acid, sodium malonate and calcium malonate.

The invention has the following beneficial effects:

(1) the enhanced retarder can effectively prolong the setting time of magnesium oxysulfate cement, the initial setting time is prolonged by more than 296%, and the final setting time is prolonged by more than 256%; the workability of the slurry is improved, and the production and construction efficiency in summer is improved.

The addition of the enhanced retarder promotes the generation of 517 crystal phase in the magnesium oxysulfate cement, obviously improves the mechanical property of the magnesium oxysulfate cement, has 28 flexural strength of more than 30.5MPa and a softening coefficient of as high as 0.9, makes the magnesium oxysulfate cement possible to replace the traditional magnesium oxychloride cement, fundamentally solves the problems of moisture absorption and halogen return of the magnesium oxychloride cement, steel bar corrosion and the like, and expands the application range of the magnesium oxysulfate cement.

The enhanced retarder is cheap and easy to obtain, weak in acidity and convenient to store.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.