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... is noteworthy to mention that a real advantage of the polycarboxylate ethers is the fact that -according to the chemical architecture -the hydration process of the alumiate cement can be controlled to some extent. In Table 1 the typical dosage rates and properties are summarized. maleic anhydride is grafted onto a polyethylene glycol chain. ...Similar publications
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... At present, superplasticizers based on naphthalene are widely used. Such as S-3 [3], and in particular on the basis of polycarboxylate esters (РСЕ) [7,[10][11][12][13][14][15]. The most studied is the use of S-3. ...
... However, it gives a significant reduction in strength after heating [8]. Additives based on РСЕ are free of this drawback [7,[10][11][12][13][14]. ...
... The slag of the current output contains significant amounts of C 12 A 7 , which causes short period of setting -the beginning of setting in 3-4 minutes. To adjust the setting time of the binder obtained, surfactant additives of various types were used, based on lignosulfonates (LST), a naphthalene base and on the basis of PSE [7,13,14,19,20]. It was found that the addition of LST is ineffective, and S-3 in an amount of up to 0,4 % allows to get the binder with the beginning of in 25-35 minutes at a normal density of 27,5 %. ...
The paper is discussing the results of the study of alumina binder and refractory concrete with additives of fine-milled high-alumina industrial wastes. The siftings of the catalyst support of dehydrogenation of hydrocarbons and ferrochromic aluminothermal slag by Kliuchevskoi Ferroalloys Corp. were used as additives. Selecting ferrochromic slag as additive is based on the fact that its content of alumina and phase composition is the closest to the alumina (CAC) and high-alumina cement (HAC). The siftings of the catalyst support of dehydrogenation of hydrocarbons consist of alumina in the active form. These additives provide increased refractoriness of cement. The information on the composition of additives is given. Superplasticizers, based on PCE, were introduced into the binder to compensate the reduction of strength. As PCE additives were used Melflux 1641F, Melflux 2641F, Melflux 2651F and Glenium 51 by BASF Constraction Polymers. The effect of additives on hydration is shown. It is established that the superplasticizers take a retarding effect on the concrete setting process. The optimal quantities of high-alumina additives and superplasticizers have been identified. The basic properties of obtained binders and concrete were investigated. The temperature of application of the developed concrete is 1,400-1,600 ° C.
This article presents the results of a comparative analysis of the dispersing effect of Russian and imported deflocculating agents based on polyphosphates and polycarboxylate ethers (PCEs) on the rheological properties of high-alumina matrix systems and their mineral components. As demonstrated, in terms of deflocculating characteristics, Russian PCEs are not inferior to analogous imported products and can be used to control the rheological behavior of low-cement refractory casting masses.
The effect of three different types of deflocculants and their amounts on high-alumina low-cement castables is studied. Castable formulations were done as per continuous particle size distribution of a Dinger-Funk model using a distribution coefficient of q = 0.21. Castable compositions were processed as per conventional processing techniques and variation in properties were evaluated regarding flowability of the mix and densification and strength development after drying and firing at 900 and 1500 °C. Phase analysis of the matrix phase was also done for the 1500 °C compositions to evaluate the phase formations at high temperature in the presence of cement. The alumina-based dispersant was found to have resulted in better properties in the castable. ABSTRACT The effect of three different types of deflocculants and their amounts on high-alumina low-cement castables is studied. Castable formulations were done as per continuous particle size distribution of a Dinger-Funk model using a distribution coefficient of q = 0.21. Castable compositions were processed as per conventional processing techniques and variation in properties were evaluated regarding flowability of the mix and densification and strength development after drying and firing at 900 and 1500 °C. Phase analysis of the matrix phase was also done for the 1500 °C compositions to evaluate the phase formations at high temperature in the presence of cement. The alumina-based dispersant was found to have resulted in better properties in the castable.
For production of fireclay refractory castables, various deflocculants are used. In recent years new polycarboxylate ethers-based deflocculants appeared and so far their properties comparing to those of common deflocculants are little investigated. This study compares the effect of content of two deflocculants, sodium tripoliphosphate and polycarboxylate ethers Castament FS-20, on hydration of aluminate cement, on structure forming during it, pH and electrical conductivity in suspensions. It was established that the increase in content of deflocculant sodium tripoliphosphate, as a binder, in the suspension results in a considerable increase of electrical conductivity, while the increase of Castament FS-20 reduces pH values. The study also evaluates the effect of content of deflocculants on duration of exothermal reaction in paste of castable with medium content of cement, on formation of structure, physicalmechanical properties of castable. It was established by means of compressive strength tests that the increase in content of sodium tripoliphosphate affects the strength properties of castables, meanwhile Castament FS-20, on the contrary, increases the compressive strength of castable samples. Dilatometric test helped to establish a different effect of deflocculants on processes of linear changes at high temperatures.
Results are provided for a study of the properties of a cement matrix of medium-cement heat-resistant concrete with deflocculant additions, i.e., sodium tripolyphosphate and polycarboxylate ester. The effect of amount of deflocculant and heat treatment temperature on the change in matrix hydration product composition after hardening at 20°C and drying at 60, 80, and 110°C is considered. Comparative analysis is performed for the change in concrete physicomechanical properties and their heat resistance is evaluated in relation to amount and type of deflocculant.
The interaction of silica fume with negatively charged polycarboxylate ethers in comparison to a polyacrylate and two non-ionic polyethylene glycols is investigated by adsorption and streaming potential measurements at slight alkaline pH value. The results indicate that polyethylene glycol is adsorbed on the silica fume in a flat conformation. Increased molecular weight however favours network formation. In contrast, the polyacrylate is adsorbed only in a very low amount due to a mutual electrostatic repulsion of the negative charged silica surface and the carboxylate groups. Polycarboxylate ether, which combine both structural features, a negative charged backbone and non-ionic polyethylene glycol side chains, adsorb via hydrogen bonding mechanism of the side chains with the silica particles. The adsorption rate of the polycarboxylate ethers predominantly increases with decreasing carboxylic equivalent. However, the adsorption affinity is determined by both, the carboxylic equivalent and the side chain length of the polycarboxylate ether.
