Studies of chemical interaction of magnesium oxide and electrolyte salt solutions

V. N. Derevianko, A. A. Maksimenko, A. Biegun, H. Hryshko

Abstract


Problem statement. Magnesia cement hydration runs very slowly, because its grains are covered with Mg(OH)2 coating,  preventing the water access to MgO. It has been also known, that periclase and magnesia cements   having burned grains can be gauged with solutions of various salts, thereby  the setting time and the strength properties are changing [5; 6].

Purpose. Creation of fast-hardening and solid structure of magnesia stone by activating MgO with electrolyte salt solutions. The effects of MgO hydration in the electrolyte-salt solutions - MgCl2 and MgSО4 was shown.

Conclusion. For the formation of magnesium stone with fast-hardening and solid structure was determined that it is necessary to apply to the method of activating MgO by electrolyte salts, and select a silica-containing component out of by-products with a surface area of grains more than 10,000 cm²/g for the formation of waterproof magnesium silicate hydrate. Samples hydrated in MgCl2 solutions of different concentrations exhibit two endothermic effects of the water of crystallization evolved at 160 and 240°C. The endothermic effect of magnesium hydroxide decomposition is shifted to 380°C. At 10 and 15 % MgCl2 concentrations, besides the above mentioned effects, at 415, 500, 520°C there are observed endothermic effects, associated with the decomposition of small amounts of magnesium oxyhydrochloride at such concentrations. It has been established that at low solution concentrations (≈ 5 %) magnesium hydroxide forms solid solutions with them. According to the data of the thermal gravimetric and chemical analyzes, the solid Mg(OH)2 solution, obtained by the hydration of MgO in 5 % MgCl2 and MgSO4 solutions, has the following limiting composition: [Mg(OH)1,88∙Cl0,22]∙0,20H2O and [Mg(OH)1,86∙ (SО4)0,07]∙0,23H2O. When mixing cement by MgO  solution of low concentration less 1,5 mol/l (13% or 1,1 g/sm) by end-product in stone structure is Mg(OH)2.


Keywords


electrolyte salts; caustic magnesite; sealer; setting up time; x-ray phase analysis; thermal gravimetric analysis

References


Adomavichyute B. B., Janickiy I. V., Viktoris B. N. Izuchenie sistemy MgO-MgSO4-H2O [ Study of MgO-MgSO4-H2O system ]. Lietuvos TSR Mokslu Akademiyos Darbai. Serija B : Chemija. Vilnius, 1961, no. 2 (25), pp. 219-226. (in Russian).

Vaganov A. P. Ksilolit (proizvodstvo i primenenie) [Xylene (production and use)]. Leningrad, Moscow, Gosstroyizdat, 1959. 144 p. (in Russian).

Zyryanova V. N., Berdov G. I., Vereshchagin V. I. Fiziko-himicheskie processy pri gidratacionnom tverdenii kompozicionnykh magnezial'nykh vjazhushhikh veshhestv [Physical and chemical processes in the hydration hardening of composite magnesia binders] Sovremennye problemy proizvodstva i ispol'zovaniya kompozicionnykh stroitel'nykh materialov, 15–16 aprelya, 2009. Materialy Vseros. konf. Novosibir. gos. arhitekturno-stroit. universitet. – Modern problems of the production and use of composite building materials, 15-16 April, 2009. Proceedings of All-Russian conference of the Novosibirsk State University of Architecture and Civil Engineering. Novosibirsk, 2009. pp. 50-52. (in Russian).

Kaminskas A. Ju. Tehnologiya stroitel'nykh materialov na magnezial'nom syr'e. Kompleksnye metody opredelenija prigodnosti syr'ja i sposoba proizvodstva [Technology of building materials magnesian materials. Complex methods for determining the suitability of materials and method of manufacture] Vil'nyus, Mokslas, 1987. 344 p. (in Russian).

Pirogov A. A. Vozdushnotverdeyushie vysokoogneupornye magnezial'nye betony [Air hardening high magnesia refractory concretes]. Ogneupory i tehnicheskaya keramika - Refractories and technical ceramics 1958, no.10, pp. 445-455. (in Russian).

Pirogov Ju. A., Fisherova A. I. Fosfatnoe svyazyvanie periklaza [Phosphate binding of periclase]. Ogneupory i tehnicheskaya keramika - Refractories and technical ceramics. 1969, no. 11, pp. 44-47. (in Russian).

Smirnov B. I., Solov'eva E. S., Segalova E. E. Issledovanie himicheskogo vzaimodejstviya okisi magniya s rastvorami hloristogo magniya razlichnykh koncentraciy [Study of the chemical interaction of magnesium oxide with solutions of different concentrations of magnesium chloride]. Zhurnal prikladnoy himii - Journal of Applied Chemistry . 1967, vol. 40, no. 3, pp.. 505-514. (in Russian).

Nikol'skiy B. P. Spravochnik himika : v 6 tomahk. Tom 1 : Obshhie svedeniya stroenie vazhneyshikh veshestv. Laboratornaya tehnika [Chemist reference: in 6 volume .Volume 1 : The general information of the structure of the most important substances]. Moscow ; Leningrad, Goshimizdat, 1963. 1071 p. (in Russian).

Kasai J., Ihiba M., Nakanara M. Mechanisme of the Hydration of Magnesia Cement. Journal of the Physical Society of Japan. 1960, vol. 63, no. 7. pp. 1182-1184.


GOST Style Citations


Адомавичюте Б. Б. Изучение системы MgО-MgSО4-H2О / Адомавичюте Б. Б., Яницкий И. В., Викторис Б. Н. // Lietuvos TSR Mokslu Akademijos Darbai. Serija B : Chemija. – Vilnius, 1961. – № 2 (25). – С. 219-226. Ваганов А. П. Ксилолит (производство и применение) / Вагонов А. П. ; [науч. ред. канд. техн. наук В. П. Шемяков]. – Ленинград ; Москва : Госстройиздат, 1959. – 144 с.

 

Зырянова В. Н. Физико-химические процессы при гидратационном твердении композиционных магнезиальных вяжущих веществ / В. Н. Зырянова, Г. И. Бердов, В. И. Верещагин // Современные проблемы производства и использования композиционных строительных материалов, 15-16 апреля, 2009 г. : материалы Всерос. конф. / Новосибир. гос. арх.-строит. университет. – Новосибирск, 2009. – С. 50-52.

 

Каминскас А. Ю. Технология строительных материалов на магнезиальном сырье. Комплексные методы определения пригодности сырья и способа производства / Каминскас А. Ю. – Вильнюс : Мокслас, 1987. – 344 с.

 

Пирогов А. А. Воздушнотвердеющие высокоогнеупорные магнезиальные бетоны / А. А. Пирогов // Огнеупоры и техническая керамика. – 1958. – № 10. – С. 445-455.

 

Пирогов Ю. А. Фосфатное связывание периклаза / Ю. А. Пирогов, А. И. Фишерова // Огнеупоры и техническая керамика. – 1969. – № 11. – С. 44-47.

 

Смирнов Б. И. Исследование химического взаимодействия окиси магния с растворами хлористого магния различных концентраций / Б. И. Смирнов, Е. С. Соловьева, Е. Е. Сегалова // Журнал прикладной химии. – 1967. – Т. 40, вып. 3. – С. 505-514.

 

Справочник химика : в 6 т. / гл. ред. Б. П. Никольский. – 2-е изд., перераб. и доп. – Москва ; Ленинград : Госхимиздат, 1963-1967. – Т. 1 : Общие сведения строение важнейших веществ. Лабораторная техника. – 1963. – 1071 с.

 

Kasai J Mechanisme of the Hydration of Magnesia Cement / J. Kasai, М. Ihiba, М. Nakanara // Journal of the Physical Society of Japan. – 1960. – Vol. 63, № 7. – Р. 1182-1184.