CC BY
37
UDK 691.311
R. Z. Rakhimov, N. R. Rakhimova, A. R.Gaifullin, O. V. Stoyanov, G. I.Yakovlev
DIFFERENTIAL THERMAL ANALYSIS OF CLAYS OF DIFFERENT COMPOSITION
Keywords: analysis, thermal, clay, composition, chemical, mineral, endoeffect, temperature range, the peak, weight.
There results of differential thermal analysis of clays with different chemical and mineral composition are described. There temperature ranges and peaks and loss of weights, characterizing endoeffects are stated.
Ключевые слова: анализ, термический, глина, состав, химический, минеральный, эндоэффект, температура, интервал, пик,
масса.
Исследована характеристика результатов дифференциально-термического анализа глин различного химического и минерального состава. Установлены температурные интервалы и пики и потеря масс, характеризующих эндоэффекты.
Introduction
Half a century ago, the famous American explorer, R.E. Grim [1] noted that the clay used as fillers last years, and judging by the trends in the development of modern industry and, especially, chemistry, this type of using will be expanded. In this regard, in his opinion, the energy of researches should be focus on this issue. Nowadays fillers of clay minerals are used in virtually all industries, particularly in the manufacture of paper, paints, adhesives, zeolites, ceramics, rubber, linoleum, roofing materials, concrete and mortars, adsorbents for cleaning oil products, wine, medicines, beer; mineral additives in cement, lime, magnesia and gypsum binder and the materials and products based on them; composite materials for immobilization of radioactive and toxic waste, etc.
It is obvious that the above-mentioned need of sending energy of researchers to promote the using of fillers of clay materials is relevant in the present time and especially for the construction industry and building materials industry, as the most material-intensive. However, the results of studies of the properties and structure of the fillers of clay materials carried out in some area of application may represent scientific and practical interest for other applications. Modification of mill ground mineral additives is one of the ways to solve problems of resource and energy conservation and ecology in the production and use of binders and materials on their basis [2,3]. Nowadays the nomenclature of mineral additives, which are introduced into the binders to increase the performance of their physical and technical properties and technical and economic efficiency includes rather a wide range of materials of natural, synthetic and technogenic origin [4]. The highest efficiency at the same time is shown at the introduction of active pozzolanic mineral additives in cements and lime binders, binding formed during mixing with water and waterproof, low-strength the calcium hydroxide in strong waterproof neoplasms. One of the first applications of ancient builders varieties of artificial pozzolanic additives was milled ceramic.
Later finely dispersed burnt clay as a pozzolanic additive has been applied in the form of tsemyanka, glinit, agloporit, burned rocks, expanded clay and expanded clay dust [4]. Tsemyanka is product of grinding baked to sintering at temperatures above
9000C and ceramic materials. Clay is baked by grinding at a temperature 600-800°C [4,5]. Lately a certain application as pozzolanic additives to improve the performance of physical and technical properties of cement composites was one of the varieties glinit -metakaolin. Metakaolin is the product of thermal processing monomineral high kaolinite clays [6,7].
However, for wide production and application of metakaolin as pozzolan certain obstacle is the limited deposits and reserves of kaolin clays in many countries, including Russia.
In this regard, the last years in many countries activated research pozzolanic activity of ubiquitous mineral clays with different contents of kaolinite and its complete absence [9,10].
In the early 40 years of the last century, such systematic studies of the pozzolanic activity of common clays were performed in the Soviet Union, as a result of which it was found that out of 207 clays from different deposits, only 11% were not suitable for the product with enough pozzolanic activity [5].
Nowadays it is expedient resumption of research activity and development from thermally activated polymineral supplements common ordinary clays in our country to create a scientific basis for the organization of their production on the basis of local clays in different regions. It is known [11] that the grindability of calcined clays depends on its chemical and mineral composition.
The activity of fine thermally activated clays additives to influence the properties of cement and lime composites depends on the characteristics of their dehydration during heat treatment.
The following are the results of differential thermal analysis (DTA) 5 varieties clays with different chemical and mineral composition.
Objects and research techniques
As objects of studies were taken the following
clays:
- New Orsk (NOC) - deposits in the Orenburg
region;
- Lower Uvelsky (LUC) - deposits in the Chelyabinsk region;
- Arsky (AC), Saray-Chekurchinskaya (SCC) and Koschakovskaya (KC) - deposits in the Republic of Tatarstan.
Tables 1-3 show the particle size distribution, chemical and mineral composition of the above mentioned clays.
Table 1 - Granulometric composition of clays which was adopted in the research
Differential thermal analysis of clays was made by using derivatograph-1500 D «Paulik - Paulik -Erdei».
There are differential thermal analysis which were adopted by researching of clays in the pic.1-5.
There is no more than 10% of swellable layers in structure of illite; mixed-layer swelling mineral has mixed-layer composition with non-swelling layers in SCC no more than 40°%, in KC no more than 20°%. Calculation is provided at 100% crystalline phase without possible content of roentgen amorphous component. (?) of clays is carried out by using diffractometer D8 Advance by Bruker company.
' "¿ "ло ¡SO "чк ''. ■■•> î» ng no >" IM» iwor
Pic. 1 - Curves DTA of LOC
590,00 С .Leo
100 I» ÏQ0 250 300 350 -Ю0 4*0 i»0 i?0 MO 6Î0 TOO 750 BOO 450 900 0J0 »0« ШОЧГ
Pic. 2 - Curves DTA of LUC
№ Varietyof clays Claysfractions%
Clayey< 0.005 мм Dusty 0.005-0.05 мм Sandy 0.051.0 мм
1 NOC 61.3 24.5 14.2
2 LUC 65 18.5 16.5
3 AC 42.2 42.8 15.00
4 SCC 49.5 37.1 13.4
5 KC 37.1 45.9 17.0
Table 2 - Ghemical composition of clays which was adopted in the research *
Varietyo fclays Н2О The content of the absolute dry weighed portion, %
SiO2 TiO2 Al2O3 Fe2O3 MnO CaO MgO Na2O K2O P2O5 SO3/S obp sum
NOC 0.81 69.18 1.36 19.55 1.32 0.01 0.20 0.42 <0.3 0.92 0.10 <0.05 6.63 99.69
LUC 0.66 66.79 0.98 20.71 1.63 0.04 0.62 0.41 <0.3 0.65 0.08 0.13 7.70 99.73
AC 1.05 73.65 1.47 15.37 2.23 0.01 0.28 0.50 <0.3 0.55 <0.03 <0.05 5.63 99.67
SCC 3.41 68.52 0.86 13.42 6.18 0.10 1.33 1.66 1.20 1.82 0.09 <0.05 4.62 99.80
KC 4.14 64.50 0.88 13.96 7.30 0.10 2.16 2.18 0.98 1.97 0.11 <0.05 5.66 99.80
*Quantitative chemical composition of clays which was determined by using ARLOPTYMX - spectrometer Table 3 - Mineral compositionof clays which adopted in the investigation *
№ п/п Variety of clays Mineral composition, %
Quartz Kaolinite Illite Mica Orthoclase Plagioclase Mixed-layer claymineral Chloride
1 NOC 41 51 8 - - - - -
2 LUC 33 62 - 4 - 1 - -
3 AC 47 40 13 - - - - -
4 SCC 28 - - 10 7 8 40 4
5 KC 34 - 5 14 40 1
Pic. 3 - Curves DTA of Arsk's clay
Pic. 4 - Curves DTA of Saray-Chekurcha's clay
There are parameters of the process of dehydration of clays on pic.1-5 in the table 4.
Analysis of the 1st endothermic effect which connected with removing of chemically bound water shows the following:
- temperature range of the 1st endothermic effect for clays with high content of kaolinite is in range 30-2500C, for clays with high content of kaolinite and its absence in range 30-2800C;
- the lowest indicators of temperature range and peak and considerable loss chemically bonded water are observed in clay with content 40% of kaolinite and 13% of illite;
- the highest loss of chemically bonded water at temperature 30-2100C is observed at clays with content mixed-layer mineral;
- weight losses in clays at temperature from 400 to 680 0C are increased with increasing content of kaolinite;
The weight loss at temperatures range 400-680 0C is connected with the loss of the main volume of hydroxyl water.
Analysis of the 3rd endothermic effect which is connected with the final loss hydroxyl water shows the following concluding:
- the temperature interval of the 3rd endoeffect at clays with kaolinite is located in range 900-600 0C, and maximum is reached at ~ 940 0C;
- clays with kaolinite 51-62% at the temperature range 900-960 0C have the lowest weight loss ~ 0,6%;
- clay with 40% of kaolinite and 13% of illite has the temperature interval 850-9500C of the 3rd endoeffect and characterized by losing weight ~ 0,8%;
- clay without kaolinepolymineralSaray-Checurchinsk's has temperature interval of the 3rdendoeffect 850-9300C and characterized by losing weight ~ 0,6%;
- clay without kaolinepolymineral Koschakovsk's has temperature interval of the 3rdendoeffect 850-9200C and characterized by losing weight ~ 0,2%.
Pic. 5 - DTA of Koschakov's clay
Table 4 -Process indicators of dehydration of clays according the differential thermal analysis.
Endoeffects and loss of weight
1stendoeffect 2ndendoeffect 3rdendoeffect
£ JS 'o <4-4 О <u "Ü > Temperatur e interval, 0С Temperatur e peak, 0C The weigh t loss, % Temperatur e interval, 0С Temperatur e peak,0C The weigh t loss, % Temperatur e interval, 0С Temperatur e peak,0C The weigh t loss, % The final weigh t loss, %
1 NO C 30-250 154,5 0,53 430-680 596,0 7,4 900-960 940,0 0,62 8,83
2 LU C 30-250 127,5 1,45 420-670 590,0 9,3 910-960 940,0 0,60 10,44
3 AC 30-170 120,0 3,5 400-660 578,0 6,0 900-960 945,0 1,20 10,86
4 SCC 30-200 157,0 3,8 380-630 541,5/572, 6 1,6 750-930 884,5 0,75 6,78
5 KC 30-210 146,5 4,1 370-620 527,5/580 2,2 850-920 881,5 0,83 7,25
5 КГ 30-210 146,5 4,1 370-620 527,5/580 2,2 850-920 881,5 0,83 7,25
References
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9.Titoni A., Castellano C.C., Bonavetti V. L., Trezza M.A., Scian A.N., Irassar E.F. Kaoliniticculcined clays - Portland cement system: Hydration and properties // Construction and Building Materials. Vol.64. August 2014. - p.215-221.
10. Habert G., Choupay N., Escadeillas G., Guillame D. et al. Clay content of argillites influence on cement based mortars // Applied Clay Science. 2009. Vol. 43. N 3-4. P. 322-330.
11. Rakhimov R.Z., Gaifullin A.R.., Rakhimova N.R., Stoyanov O.V.The grindability of calcined clays, depending on their composition and temperature of thermal treatment // VestnikKSTU - 2015,Vol.18, №1. - p. 168-172.
© R. Z. Rakhimov - professor, Kazan State University of Architecture and Engineering, rahimov@ksaba.ru; N. R. Rakhimova -professor, Kazan State University of Architecture and Engineering, rahimova07@list.ru; A. R. Gayfullin - docent, Kazan State University of Architecture and Engineering, gaifi@list.ru; O. V. Stoyanov - professor, Kazan National Research Technological University, Department of Plastics Technology, ov_stoyanov@mail.ru; G. 1 Yakovlev - professor, Izhevsk State Technical University.
© Р. З. Рахимов - проф. КГАСУ, rahimov@ksaba.ru; Н. Р. Рахимова - проф. КГАСУ, rahimova07@list.ru; А. Р. Гайфуллин -доц. КГАСУ, gaifi@list.ru; О. В. Стоянов - д-р техн. наук, проф., зав. каф. технологии пластических масс КНИТУ, ov_stoyanov@mail.ru; Г. И. Яковлев - проф., Ижевского госуд. технич. ун-та.
