Effects of Disodium Hydrogen Phosphate Addition and Heat Treatment on the Formation of Magnesium Silicate Hydrate Gel

The formation of magnesium silicate hydrate gel is crucial in preventing magnesia aggregates from over hydrated during the construction of refractory castables since the presence of magnesium hydroxide diminish the mechanical properties of the material. This work aimed to investigate the accelerating effects of sodium hydrogen phosphate and heat treatment on the formation of magnesium silicate hydrate gel. Time-dependent pH of magnesia - silica fume slurries with and without sodium hydrogen phosphate addition and heat treatment was measured to verify the dissolution of MgO and magnesium silicate hydrate formation. The effects of sodium hydrogen phosphate were differentiable only at small added amounts, whereas heat treatment at 50 degrees Celsius performed noticeable acceleration. This observation could be applicable in molding to maintain the stability of basic refractory castables.

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ПРИДАНИЕ ОГНЕЗАЩИТНЫХ СВОЙСТВ ЦЕЛЛЮЛОЗНЫМ ТЕКСТИЛЬНЫМ МАТЕРИАЛАМ С ПРИМЕНЕНИЕМ ЗОЛЬ - ГЕЛЬ ТЕХНОЛОГИИ

chemistry of plant raw material ◽

10.14258/jcprm.2019044286 ◽

2019 ◽

pp. 365-372

Author(s):

Bijamal Raimovna Tausarova ◽

Anastasiya Yur'yevna Stasenko

Keyword(s):

Heat Treatment ◽

Flame Retardant ◽

Sodium Silicate ◽

Ignition Time ◽

Fire Retardant ◽

Hydrogen Phosphate ◽

Sodium Hydrogen Phosphate ◽

Sodium Hydrogen ◽

Fire Retardant Properties ◽

Flame Retardant Properties

The article presents studies on the use of a new composition based on sodium silicate, urea and sodium hydrogen phosphate to impart fire-retardant properties to cellulosic textile materials. The influence of the concentration of the starting components, temperature, and heat treatment time on the flame retardant properties was studied. The change in the fire retardant properties of cotton fabric is given for three heat treatment modes: at 80, 90 and 100 °C. Compared to the initial fabric, the samples treated with a flame retardant have indicators of flame retardant properties. Untreated fabric with a size of 220×170 mm when tested for flammability at an ignition time of 15 s completely burns out in 60 s. In samples treated with a flame retardant, at an ignition time of 15 s, the smoldering time is practically reduced to zero. With an increase in the concentration of the flame retardant, and the temperature of the heat treatment, the loss of material strength, breaking load, and the appearance of the fabric change slightly. Using electron scanning microscopy and energy dispersive microanalysis, it was shown that pure cotton fabric contains 68.77% carbon and 31.22% oxygen; after modification, particles of sodium – 0.02%, phosphorus – 0.04% and potassium – 0.05% are formed on the surface of the treated fabric. distributed fairly unevenly. It has been shown that in cellulosic materials modified with compositions based on sodium silicate and urea, sodium hydrogen phosphate, flame retardant properties increase. The proposed composition provides the achievement of higher fire resistance. Processing can be carried out on standard equipment of finishing enterprises without the stage of high-temperature fixation of the drug.

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