Physico-chemical studies of Arvaten basalt for the production of mineral fiber

. The article carried out complex studies to determine the chemical, chemical-mineralogical composition, acidity and viscosity modules of basalt from the Arvaten deposit. It has been established that the basalts of this deposit can be used as a raw material for the production of stone casting materials, in the form of mineral wool, as well as basalt fiber with corrective additives


Introduction
In the development of the modern construction industry, it is aimed at creating energy-and resource-saving technologies for the production of cheap and competitive materials and products.The improvement of modern energy saving technologies in the building materials industry is impossible without the use of efficient and affordable heat-insulating materials with desired properties.Currently, in our Republic, there is a widespread increase in the use of heat-insulating materials and structures, which are one of the modern building materials.In this regard, the strategic focus in the production of these materials is directed to new innovative approaches to the development of their effective compositions and production technologies.In this regard, the problem of searching for promising domestic raw materials for the development of an effective composition of thermal insulation materials and their innovative production technologies is of relevance for the development of the real sector of the economy of Uzbekistan [1][2][3][4].
Based on the above, the problems of creating and implementing innovative technologies for the production of popular building materials, in particular heat-insulating products, come to the fore.It is known that the development of production and the increase in the need for heat-insulating materials requires them to be produced from non-deficient domestic raw materials.These problems can be solved through the development of innovative technologies for the production of these materials, which will provide demand in the domestic market and will help reduce their imports and create export opportunities [5].
The Republic has huge reserves of natural non-metallic raw materials, including promising deposits of igneous rocks of various origins, which can serve as a promising raw material for the production of heat-insulating materials.
In this work, research is aimed at expanding the raw material base for obtaining heatinsulating materials based on local raw materials.In this regard, this paper presents the results of a study to establish the suitability of igneous rock, in particular, the basalt of the Arvaten deposit for the production of mineral wool.

Experimental
In the work, samples of basalts from the Arvaten deposit, which are located in the Jizzakh region, were used as raw materials for the production of mineral wool.[6][7][8].
This deposit of basalt rocks has the necessary reserves for their industrial processing.
The preparation of various fractional compositions of basalt and serpentinite was carried out as follows: previously elutriated basalts and serpentinites were dried at a temperature of 110-130°C in a laboratory oven, then crushed in jaw crushers to a raw granule size of 20 mm, then the obtained igneous rock granules were subjected to fine grinding, for which used ball mills with uralite balls.Roasting and pulping were carried out in corundum crucibles of a laboratory silicate furnace at a temperature range of 1100-1400°C.The process of obtaining a melt based on basalt, i.e.The melt formation of compositions in high-temperature treatment consisted of the following stages: first, the samples were heated to a temperature of 1000°C at a rate of 300°C, in the temperature range from 1000 to 1300°C at a rate of 50°C, from a temperature of 1300 to 1500°C at a rate of 300°C for an hour.In the last stage for the homogenization of the glass mass, the holding time was 8 hours.A thread was drawn from the resulting melt, and also quenched in cold water.
To determine the chemical and mineralogical composition of the raw materials used and the main characteristics of prototypes based on it, they studied using chemical and X-ray phase analyzes, as well as the generally accepted calculation of the acidity and viscosity modulus [9][10][11][12][13][14].
From the technology of stone casting it is known that the properties of products in the form of basalt fibers are determined mainly by the initial material composition of the raw material component, as well as the value of the acidity modulus (Ma) and the viscosity modulus (Mv).At the same time, the value of the acidity modulus for basalt onecomponent mixtures should be in the range from 2.00 to 2.17 [13,15].It should be noted that the viscosity modulus of one-component batches for normal fiber drawing, according to the authors of [12,16], should be in the range of 2.2-3.2.
The acidity modulus of a basalt sample, taking into account the chemical composition, was determined according to [13] using the following equation: where: XRmOn is the mass fraction of oxides in the composition.
The viscosity modulus of prototypes is calculated by the formula [12 10]: where: MRmOn is the molar content of oxides in the composition of the mixture under study.
To study the chemical and mineralogical compositions of basalt rocks, the method of powder X-ray diffraction was used, which was performed on a Shimadzu X-ray diffractometer with СuKα radiation.X-ray photographs were taken with a step of 0.05, the mode of current and voltage of the tube was 30 mA, 40 kV.The X-ray power was 2 kW.Identification of mineral phases and analysis of the results was carried out using reference books and an international database [17][18][19].

Results and discussion
As a result of X-ray spectral analysis of samples (Table 1) of Arvaten basalt (AB) the presence of 16 and 17 chemical elements was determined, respectively.Of these elements, the main rock-forming elements are silicon, calcium, aluminum, iron, the remaining elements are present in small amounts.The results of a study on the material composition of samples of a basalt rock sample showed that the content of basic oxides satisfies the requirements for raw materials for fiber production.The results of determining the chemical composition of the Arvaten basalt (AB) samples are shown in Table 2. Loss on ignition (LOI) includes: water, organic and volatile impurities and carbon dioxide (CO2).

Name of samples
Table 3 shows the calculated acidity moduli and viscosity moduli of the studied samples of basalt from the Arvaten deposit according to the data on the chemical composition of the rock, respectively.
As can be seen from the data in Table 3, in terms of acidity modulus -Mk, the basalts of the Arvaten deposit correspond to the production of mineral wool.The viscosity modulus of these basalt samples is in the range of 0.95-1.09,and the average viscosity modulus is 1.02.At the same time, it should be noted that the basalts of the Arvaten deposit, in terms of viscosity modulus, belong to low-viscosity rocks, and in a single-component form, interruption was observed in the process of fiber drawing.Therefore, when developing the composition, it is necessary to adjust with modifying additives.On the basis of the results of the studies carried out to determine the melting temperature of samples of Arvaten basalts, it was shown that due to the presence of impurities in the composition of the rock, they melt in the range from 1350 to 1450°C.
The results of X-ray phase analysis [20,21] of experimental samples from the basalt of the Arvaten deposit showed that the main rock-forming mineral is albite (Fig. 1).

Fig.1. X-ray diffraction pattern of samples of basalt from the Arvaten deposit
According to the qualitative X-ray analysis of the original sample of the Arvaten basalt, the presence of diffraction reflections corresponding to the minerals of quartz, chlorite, albite, calcite and illite is observed, the results are shown in Table 4.The chemical and mineralogical compositions, acidity and viscosity modulus of the Arvaten basalt were determined by the methods of chemical, X-ray phase and X-ray spectral analyses.Based on the results of the analysis, it was found that the basalts of this deposit can be used as a raw material for the production of stone casting materials, in the form of mineral wool, as well as basalt fiber with corrective additives.In addition, taking into account the favourable location and large reserves of basalts from the Arvaten deposits, it will expand the raw material base for the production of heatinsulating materials for various purposes.

Table 1 .
The results of X-ray spectral analysis of experimental samples of Arvaten basalt

Table 3 .
Chemical compositions of basalt rocks of the Arvaten deposit

Table 4 .
Results of X-ray diffraction patterns of basalt samples from the Arvaten deposit