RU2559964C1 - Fluoroflogopite-based mica crystal material and method of its production - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: fluoroflogopite-based mica crystal material contain silicon oxides, aluminium, magnesium, potassium and fluorine, note it contains the named ingredients at the following ratio, wt %: silicon oxide - 39.0-43.0, aluminium oxide - 9.0-12.0, magnesium oxide - 27.1-30.0, potassium oxide - 7.1-9.0 and fluorine - 8.0-12.0. The method of fluoroflogopite-based mica crystal material production includes the preparation of furnace charge from the following components, wt %: quartz sand - 33.5-34.5, alumina - 9.5-10.5, periclase powder - 29.5-30.5, potassium silicofluoride - 25.5-26.5. Briquettes are melted at the temperature 1600-1800°C within 1.5-3.5 hours.

EFFECT: improvement of strength and increase of service life of refractory-lined material.

4 cl, 1 ex

Description

The invention relates to the composition and production technology of mica-crystalline material based on fluorophlogopite, which can be used as an insulating material, as well as a lining and structural material for wear parts and components of thermal metallurgical units operating under high temperatures (not more than 1200 ° C), aggressive media (chlorine, hydrogen chloride, melts of chlorides of alkali and alkaline earth metals) and melts of light and non-ferrous metals (aluminum, zinc, copper, magnesium, titanium, etc.) and alloys based on them.

The known composition of the material based on stone casting (ed. Certificate of the USSR No. 649669, publ. 02.28.1979, bull. 8) containing silicon oxide, titanium oxide, aluminum oxide, iron oxides, calcium oxide, magnesium oxide, sodium oxide and oxide potassium, in addition, it additionally contains fluorine in the following ratio of ingredients, weight. %:

silicon oxide - 41.4 - 44.0,

titanium oxide - 0.5 1.0,

aluminum oxide - 6.0 - 9.0,

iron oxide - 0.1 - 0.5,

iron oxide - 0.4 -1.0,

calcium oxide - 0.5 - 4.5,

magnesium oxide - 28.0-30.0,

sodium oxide - 0.1-1.0,

potassium oxide - 4.0-7.0,

fluorine - 5.0-9.0.

A known method of manufacturing the specified material based on stone casting, including the preparation of a mixture based on sand, clay, alumina, magnesite, fluorine-containing technical raw materials. The mixture is melted at a temperature of 1500-1550 ° C in a gas or electric melting furnaces. The resulting castings crystallize at 850-900 ° C, and then annealed. During crystallization of the melt, a material of a homogeneous full-crystalline structure is formed, containing not more than 5% of the free glassy phase. The mineral composition of the casting is represented by enstatite, pyroxene of complex composition and fluorine minerals. This provides the material with high chemical resistance.

The disadvantage of this composition and its production method is that stone casting contains a high content of silicon, which adversely affects the properties of the material. It is known that the increased content of quartz sand is associated with the appearance of extraneous mineral phases in the castings, which leads to a deterioration in the properties of the material. The increase in the content of quartz sand above 34.5 wt. % causes the appearance of crystallobalite and enstatite. In addition, the use of wet powder mixture for the production of stone casting leads to the loss of fluorine-containing raw materials due to the interaction of raw materials with water (pyrohydrolysis reaction). In this case, fluorine compounds of new crystalline forms are formed, which leads to intensive destruction of castings and to a decrease in the strength properties of the material.

The known composition of the material based on stone casting (ed. Certificate of the USSR No. 992446, publ. 01/30/1983, bull. 4) containing silicon oxide, aluminum oxide, magnesium oxide, potassium oxide, silicon carbide and fluorine in the following ratio of ingredients, weight . %:

silicon oxide - 41.4 - 44.0,

aluminum oxide - 8.3 - 9.8,

magnesium oxide - 25.0 - 26.3,

potassium oxide - 7.9 - 8.7,

fluorine - 9.0-9.5,

silicon carbide - 3.0 - 7.0 in the form of a powder fraction of 10-50 microns.

A known method of producing the above material based on stone casting (ed. Certificate of the USSR No. 992446, publ. 01/30/1983, bull. 4), including the preparation of a mixture based on sand, alumina, periclase, potassium silicofluoride and silicon carbide, melting the mixture in electric arc furnaces, pouring the obtained melt into molds and crystallization of the melt while it solidifies. The result is castings of a given shape for use in industry as lining and structural elements in thermal units. This allows you to increase the service life of units by 1.5-2.0 times and reduce the costs associated with their repair.

The disadvantage of this composition of the material based on stone casting and the method of its production is that silicon carbide, which does not dissolve when melted in a silicate melt, is used as an additive to the claimed composition. Solid silicon carbide particles are the centers around which fluorophlogopite crystals grow. Particulate matter settles down under its own weight, and the uniformity of the mass is broken. As a result, material zones enriched with carbide with greater strength and zones containing fewer particles with lower strength arise. This leads to heterogeneity of the material and to deterioration of the strength properties of castings, reduces corrosion resistance and reduces the service life of thermal metallurgical units.

The known composition of the material based on stone casting (ed. Certificate of the USSR No. 759472, publ. 30.08.80, bull. No. 32) containing silicon oxide, aluminum oxide, calcium oxide, magnesium oxide, potassium oxide, barium oxide and fluorine in the following ratio of ingredients, weight. %:

silicon oxide - 32.5-38.5,

aluminum oxide - 12.5 - 15.0,

calcium oxide - 0.8 -1.6,

magnesium oxide - 24.0 - 25.7,

potassium oxide - 4.8 - 7.0,

fluorine - 8.0-9.0,

barium oxide - 7.0 - 13.5.

The material has a compressive strength of 730-900 kgf / cm ² , an increased number of heat exchangers that can withstand samples without destruction when exposed to high temperatures of 900 and 1050 ° C. The amount of free glassy phase ranges from 5-10%.

A known method of producing the specified material based on stone casting (ed. Certificate of the USSR No. 759472, publ. 30.08.80, bull. No. 32), including melting a mixture based on sand, clay, alumina, magnesite, periclase, potassium fluoride, magnesium fluoride with barite concentrate additives. Melting is carried out at a temperature of 1600-1700 ° C. The melt is poured into molds, where crystallization occurs during solidification. The obtained castings are subjected to annealing (slow cooling). The mineral phase is represented by crystals of solid solutions of fluoroflogopite potassium-barium composition.

The disadvantage of this material based on stone casting and the method of its production is that inorganic fluorides are used to produce castings from material based on stone casting, which, when loaded into a smelting furnace of a wet mixture, become volatile as a result of pyrohydrolysis of fluorides:

The formation of gaseous hydrogen fluoride produces fluoride compounds in a bound form, which leads to the loss of fluoride compounds and the formation of extraneous mineral phases in the castings. The stone castings obtained from the specified material are obtained with deteriorated properties and are destroyed by aggressive molten and gaseous media. As industrial tests have shown, the rate of destruction of stone casting is 0.35-0.6 mm per day and leads to a change in the shape of the casting by 3-5 mm per day. This affects the strength properties of the casting, reduces corrosion resistance and leads to a decrease in the service life of thermal units to produce light and non-ferrous metals.

The known composition of the glass-ceramic material based on fluoroflogopite (US patent No. 4777151 from 10/11/1988, priority of Japan No. 60-144555 from 07/03/1985), including components in the following ratio of ingredients, weight. %:

silicon oxide - 35-60,

alumina -10-20,

magnesium oxide -12-25,

potassium oxide - 5-15,

fluorine - 4-15.

The content of microcrystalline fluorophlogopite in the glass-ceramic material is 40-70 weight. %

A known method of production of the specified glass-ceramic material based on fluorophlogopite (US patent No. 4777151 from 10/11/1988, priority of Japan No. 60-144555 from 07/03/1985), including the stage of dehydration and drying of the mixture at a temperature of 25-130 ° C and the stage of heat treatment first at at a temperature of 500-800 ° C for 1-15 hours, then at a temperature of 800-1100 ° C for 1-15 hours, the stage of pouring into the mold with cooling. The stage of final heating of the casting at a temperature of 1100-1300 ° C for 1-15 hours, the removal of scale from the casting and an increase in the growth of the fluorophlogopite microstructure. The resulting glass-ceramic material has a bending strength of not less than 1500 kgf / cm ² , heat resistance of about 1800 ° C, high dielectric ability and good machinability. The material has high tensile casting properties.

The disadvantage of this glass-ceramic material based on fluoroflogopite and the method of its production is the low content of fluorophlogopite (40-70 wt.%) In the glass-ceramic material. This leads to brittleness of the material and to increased porosity, and does not allow it to be used under conditions of exposure to high temperatures and aggressive environments, namely in thermal metallurgical units for producing light and non-ferrous metals. In addition, the process of obtaining fluorophlogopite is a lengthy process, each operation lasts 1-15 hours, which reduces the productivity of the process of obtaining fluorophlogopite.

A known method of crystallosynthesis of fluorophlogopite (ed. Certificate of the USSR No. 168261, publ. 11/18/1965, bull. No. 4), including drying the components of the mixture at a temperature of 600-800 ° C, mixing, pressing into granules and loading the obtained granules into a crucible. Melting and homogenization of the melt is carried out at a temperature of 1400 ° C for 6-8 hours, crystallization of the melt in a mold to produce castings and their gradual cooling in platinum crucibles in the temperature range 1360-1325 ° C with decreasing temperature at a speed of 1 deg / hour at a temperature gradient of 1-2 degrees / cm. The whole process of crystallosynthesis lasts from 4 to 6 days. As the mixture using natural potassium feldspar containing impurities of sodium oxide up to 3.5%, calcium oxide up to 0.4%, iron oxide up to 0.3% with the addition of magnesium oxide and magnesium fluoride. In order to improve the crystallization ability of the melt and compensate for the loss of volatiles, 2.5% of potassium silicofluoride is introduced into the main charge. The result is a mica crystal material with large crystals 70-45 mm long and 3-4 mm thick.

The disadvantage of this method is that the mica material is obtained with large crystals, a length of 70-45 mm and a thickness of 3-4 mm An increase in the crystal size in the microstructure of fluorophlogopite leads to an increase in porosity, which does not allow the obtained fluorophlogopite to be used in aggressive environments due to penetration of molten metal chlorides into the pores of fluorophlogopite and a decrease in the service life of the lining material. In addition, in the process of obtaining mica crystalline material, side compounds are formed due to the reaction of pyrohydrolysis of the interaction of potassium silicofluoride with water. As a result of the pyrohydrolysis reaction, the resulting hydrogen fluoride reacts with the charge components with the formation of fluorides and oxyfluorides, which leads to the loss of fluoride compounds and to the formation of undesirable side compounds and the appearance of extraneous mineral phases in the castings with a deterioration in their properties. All this leads to a decrease in the strength properties of the material. In addition, the process of preparing fluoroflogopite is lengthy from 4 to 6 days, which reduces the productivity of the process of obtaining mica-crystalline material based on fluoroflogopite.

Known electrical insulation material (ed. Certificate of the USSR No. 883979, publ. 11/23/1981, bull. No. 43), by the number of common features adopted for the closest analogue prototype and including oxides of silicon, aluminum, magnesium, potassium and fluorine in the following ratio of ingredients , the weight. %:

silicon oxide - 43.8-44.8,

aluminum oxide - 6.8 -8.0,

magnesium oxide - 25.0 - 27.0,

potassium oxide - 9.5 - 10.5,

fluorine - 12.0-13.0.

The specified material has enhanced physical and mechanical properties in combination with reduced water absorption (0.5-1.3%), density (2.7-2.8 g / cm ³ ) and porosity (0.5-1.5%) , while the value of water absorption is reduced by 2-3 times.

The disadvantage of this composition is that the high fluorine content in the claimed composition (12.0-13.0 wt.%) Leads to the production of coarse-crystalline material, and an increase in crystal growth in the microstructure of fluorophlogopite leads to an increase in porosity, which does not allow the use of the obtained fluoroflogopite in aggressive environments due to penetration of molten metal chlorides into the pores of fluorophlogopite.

There is a method of producing fused cast material for lining thermal units of non-ferrous metallurgy (RF patent No. 2410349, publ. 01/27/2011), by the number of common features adopted for the closest analogue prototype and including the preparation of the components of the mixture, consisting of quartz sand, metallurgical magnesite, alumina and fluorine-containing components, melting the resulting mixture, pouring the melt into molds, holding, extracting the casting from the mold, annealing and cooling. Refractory clay is used as an alumina-containing component, aluminum fluoride or magnesium fluoride is used as a fluorine-containing component and additionally potash in the following ratio of components, mass. %:

silica sand 23.8-38.9,

metallurgical magnesite 15.2-29.4,

refractory clay 4.3-31.5,

fluorine-containing component 17.1-18,

potash -15.2-16.8.

The preparation of the mixture includes the following operations: weighing, mixing the powdered components of the mixture with strict dosing of the components, moistening the mixed mixture with water to obtain a plastic mass, forming a pelletized mixture in the form of granules with a diameter of 5-20 mm, and drying them. The granules are melted for 1 hour at a temperature of 1450-1550 ° C. With the melt fluorophlogopite. Then, the resulting melt is casted in a continuous stream upon reaching the melt temperature of 1430-1450 ° C into molds heated to a temperature of 200-500 ° C. Annealing of the castings is carried out at a temperature of 800-900 ° C, followed by cooling in a furnace at a speed of 35-45 ° C / h. The fused cast material has improved strength properties and contains crystals in the form of spherulites with a diameter of 5-10 mm.

The disadvantage of this method of production of fused cast material is that as a mixture using potash with a potassium oxide content of 15.2-16.8 mass. % The increased content of alkali metal oxides, in particular potassium oxide, more than 10 wt. % affects the amount and composition of the free glassy phase in the castings, as well as the composition of the main crystalline aggregate of the material, since the residual potassium-containing glassy phase becomes more fusible. As shown by pilot tests of castings prepared from fused-cast material of the specified composition, at a temperature above 900 ° C, the glassy phase evaporates from the bulk of the crystalline material. Correspondingly, an aggressive melt of chlorides of alkali and alkaline earth metals begins to flow into the resulting pores, which leads to intensive destruction of castings and to a decrease in the strength properties of the material. In addition, in said patent a fused-cast material with crystals in the form of spherulites with a diameter of 5-10 mm is obtained. The large size of the crystals leads to a decrease in the corrosion properties of the material by 40%. This does not allow the use of the obtained fluorophlogopite in aggressive environments of thermal apparatus due to the penetration of molten metal chlorides into the pores of the fluorophlogopite. All this leads to a decrease in the strength properties of the material and, accordingly, to a decrease in the service life of the lining material.

The technical result is aimed at eliminating the disadvantages of the prototype and allows to obtain castings with a smooth, even surface. The outer casting surface, formed by very small differently oriented fluorophlogopite crystals bonded by a glass phase, is the most dense and durable part of the castings, which determines their corrosion resistance under conditions of exposure to high-temperature aggressive environments. To obtain mica-crystalline material based on fluorophlogopite, an optimally selected composition and ratio of charge materials and optimal conditions for the production process were used. This allows the subsequent melting and obtaining a melt of mica-crystalline material based on fluoroflogopite to avoid losses of fluoride compounds by reducing the formation of gaseous hydrogen fluoride, fluoride and oxyfluoride compounds and to eliminate the formation of undesirable crystalline phases. On the surface (top layer) of the castings there are no cracks, sinks, mechanical damage. The content of the main mineral phase, fluorophlogopite, ranges from 75 to 92% by weight, and the glass phase content does not exceed 2-3%. The size of the crystals in the surface zone of the casting does not exceed 0.2-0.3 mm, the porosity of the material is 0.5-1%.

The objective of the invention is to obtain mica-crystalline material based on fluoroflogopite with improved heat and corrosion-resistant properties, which allows to increase the service life of equipment in which castings are used, 2-4 times. In addition, the proposed technology for the production of mica crystalline material based on fluoroflogopite can improve the productivity of the process of its production.

The problem is solved by the fact that the proposed mica-crystalline material based on fluorophlogopite, including oxides of silicon, aluminum, magnesium, potassium and fluorine, while it contains these ingredients in the following ratio, mass. %:

silicon oxide - 39.0 - 43.0,

aluminum oxide - 9.0 -12.0,

magnesium oxide - 27.1 - 30.0,

potassium oxide - 7.1 - 9.0,

fluorine - 8.0 - 12.0.

The problem is also solved by the fact that the proposed method for the production of mica crystalline material based on fluoroflogopite according to claim 1, including preparing the components of the mixture, mixing, adding water to the mixture to obtain a plastic mass, its formation, drying, melting to obtain molten mica-crystalline material, pouring it into casting molds, holding castings, extracting castings from casting molds and annealing them with gradual cooling, in which it is new that the mixture is prepared from quartz dog a, alumina, periclase kremneftorida powder and potassium, with the following component ratio, wt. %:

quartz sand - 33.5 - 34.5,

alumina - 9.5 -10.5,

periclase powder - 29.5 - 30.5,

potassium silicofluoride - 25.5 - 26.5,

to obtain a plastic mass, a heated solution of lignosulfonates is used as a binder component, which is supplied simultaneously with water to the mixture with continuous stirring for 15-20 minutes to a mass moisture content of 3-8%, the plastic mass is formed in the form of briquettes and dried stepwise at first at a temperature 100-200 ° C, then at a temperature of 200-300 ° C for 2-3 hours, the briquettes are melted at a temperature of 1600-1750 ° C for 1.5-3.5 hours, and the castings are annealed at a temperature of 910-950 ° C with an isothermal discharge at this temperature buckle for 1-3 hours and subsequent cooling rate of 30-60 ° C / hour. In addition, the mixture is mixed for 15-30 minutes. In addition, the lignosulfonate solution is heated to a temperature of 60-80 ° C.

In addition, briquettes form a size of 20 × 50 mm.

In addition, the molten mica-crystalline material is kept in casting molds for 15-30 minutes.

In addition, the molds are heated to a temperature of 150-200 ° C before pouring the molten mica-crystalline material.

In addition, the castings are annealed for 22-24 hours.

In addition, the castings are cooled to a temperature of 50-80 ° C.

The experimentally selected qualitative and quantitative composition of mica-crystalline material based on fluoroflogopite in a strictly dosed ratio of ingredients allows to obtain mica-crystalline material based on fluorophlogopite with high strength properties, with a dense fine-grained structure and low porosity, which allows castings to be used as a lining and as parts in aggregates with aggressive media, increasing the life of the unit. The empirically selected intervals of the ingredients of the mica crystal material make it possible to control the composition of the free glassy phase in the casting and the composition of the main crystalline aggregate of the material. With an increase in the content of potassium oxide above 9 wt. The% glassy phase of the material becomes more fusible, and at high temperatures it evaporates from the material, which leads to intensive destruction of the castings and a reduction in their useful life. With a decrease in the content of potassium oxide below 7%, the formation of new crystals, for example, Celsian, leads to intensive destruction of the castings and a decrease in their useful life. A change in the amount of silicon, magnesium, and aluminum oxides above or below the specified limits is associated with the appearance of extraneous mineral phases in the castings and the deterioration of their properties. With an increase in the amount of alumina above 12 wt. % and magnesium oxide more than 30 wt. % in the material there is an admixture in the form of spinel, an increase in the content of silicon oxide above 43 wt. % causes the appearance of crystallobalite and enstatite. A decrease in the content of oxides of silicon, aluminum and magnesium below the declared limit values leads to the formation of large crystals and to an increase in porosity. The material of the coarse-grained structure and high porosity is also formed when the fluorine content is above 12 wt. % With a decrease in fluorine content of less than 8 wt. % in the material, a large number of foreign compounds are formed in the form of crystals such as spinel, enstatite, forsterate, which reduce the fluorophlogopite content in mica-crystalline material and impair the strength properties of mica-crystalline material.

Experimentally selected qualitative and quantitative composition of the mixture to obtain mica-crystalline material based on fluoroflogopite allows to obtain a material with high strength properties. Briquettes made from these charge materials have low porosity, are not impregnated with a metal chloride melt, and are the most resistant to aggressive media. A change in the amount of quartz sand, alumina, periclase powder above or below the specified limits is associated with the appearance of extraneous mineral phases in the briquettes and the deterioration of their properties. With an increase in the amount of alumina above 10.5 wt. % and periclase powder more than 30.5 wt. % in the material there is an admixture in the form of spinel, an increase in the content of quartz sand above 34.5 wt. % causes the appearance of crystallobalite and enstatite. A decrease in the content below the declared limit values leads to the formation of large crystals and an increase in porosity.

The use of a lignosulfonate solution heated to a temperature of 60-80 ° C as the binder component and the modes of preparation of the plastic mass with stirring make it possible to obtain briquettes of a more enlarged shape and strong composition. This allows the subsequent melting operation and the production of a melt of mica-crystalline material based on fluorophlogopite to avoid the loss of fluoride compounds by reducing the formation of gaseous hydrogen fluoride, fluoride and oxyfluoride compounds, and to eliminate the formation of side unwanted crystalline phases.

The drying operation of the obtained briquettes is stepwise: first at a temperature of 100-200 ° C, then at a temperature of 200-300 ° C for 2-2.5 hours to a mass moisture content of 0.11-0.2% allows for the subsequent melting operation and to obtain a melt of mica-crystalline material based on fluorophlogopite to avoid losses of fluoride compounds by reducing the formation of gaseous hydrogen fluoride, fluoride and oxyfluoride compounds and to eliminate the formation of undesirable crystalline phases.

The selected mode of carrying out the operation of melting the briquettes of the charge (temperature 1600-1750 ° C and a melting time of 1.5-3.5 hours) also avoids the formation of adverse reactions that contaminate mica-crystalline material with compounds that are different in composition from fluorophlogopite. The silicate system for producing mica crystalline material based on fluoroflogopite contains inorganic fluorides, which become volatile when the mixture is melted in the temperature range 1300-1500 ° C. Their volatility is enhanced in the case of melting of the wet mixture as a result of the reaction of pyrohydrolysis of fluorides.

Experimentally selected modes of operations for the production of mica-crystalline material based on fluorophlogopite, for example, the duration of the melting process, 1.5-3.5 hours, holding in molds for 15-30 minutes, can increase the productivity of the process and reduce the formation of harmful impurities in the material, eliminate defects of layered flows and the formation of neslitins on the surface of castings and thereby increase the resistance of castings to aggressive environments.

The selected mode of annealing of the castings in the furnace at a temperature of 910–950 ° C and the isothermal holding at this temperature for 1.5–3.0 hours allows increasing the density of the material in the casting due to shrinkage, compaction, and structure formation, which significantly increases the strength properties of the material .

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, and the identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by features that are identical (identical) to all the essential features of the invention. The determination from the list of identified analogues of the prototype as the closest in terms of the totality of the features of the analogue made it possible to establish the combination of the distinguishing features that are essential to the applicant’s technical result in the claimed mica-crystalline material based on fluoroflogopite and the method of its production set forth in the claims. Therefore, the claimed invention meets the condition of "novelty."

To verify the compliance of the claimed invention with the condition "inventive step", the applicant conducted an additional search for known solutions in order to identify features that match the distinctive features of the claimed method from the prototype. In the claimed invention there is a new set of features, expressed in a new sequence of actions in time, new additional stages of the process and in new conditions for the implementation of actions. Therefore, the claimed invention meets the condition of "inventive step".

The industrial applicability of the invention is confirmed by the following example of the method for the production of mica-crystalline material based on fluoroflogopite. Mica-crystalline material based on fluorophlogopite, the structural formula [KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ ] is a product of high-temperature smelting of iron-free mineral raw materials with the addition of potassium silicofluoride in the mixture and consists of three structural components: fluorophlogopite (75-92%), accessory elements (5-10%) and glass phase (2-3%). The following components are used as raw materials for the preparation of a mixture for the production of mica-crystalline material based on fluoroflogopite:

silica sand, grade BC-050-1 (GOST 22551-77) in an amount of 340 kg (34.0 wt.%),

GO brand alumina (GOST 30558) in an amount of 100 kg (10.0 wt.%),

periclase powder brand PPI-91 or PPTI-92 (GOST 10360-85) in an amount of 300 kg (30.0 wt.%),

technical potassium fluoride fluoride (TU 2621-017- 69886968-2013) in the amount of 260 kg (26.0 wt.%).

Fluorophlogopite by its nature is a complex compound of variable composition, and its synthesis is carried out through the formation of a number of intermediate compounds. The components of the charge are loaded into hoppers with vibration dosing units and fed through a loading unit to a cube moved on an electric trolley under the hoppers. The trolley is equipped with 4D-P-3-2000-A.W / 4D electronic scales, with the help of which additional (to volume dosing) weight control of charge components is carried out. The plug with the charge is installed on the receiving funnel of the mixing machine type MS-400M with a rotating mixer with a rotational speed of the blades equal to 55 rpm As a binder for the charge, a solution of lignosulfonates (TU 2455-028-00279580) in the amount of 3.5 wt% (35 kg per 1 ton of charge) is used, heated to a temperature of 70 ° C in the tank of the resistance furnace. A dry mixture is loaded into the MC-400M mixing machine and water and a solution of lignosulfonates are fed onto its surface, mixed for 20 minutes and a plastic mass with a moisture content of 8% is obtained. The plastic mass is discharged into a cube, which is mounted on a receiving funnel of a roller press, which is two drums rotating towards each other. In a roller press with a productivity of 5 t / h, briquettes of size 20 × 50 mm are obtained. Briquettes are sent to step drying. First, the briquettes are poured onto a plate conveyor and loaded into a conveyor furnace of the SKOP-9.5.1, 15.31, 7 / 1.5 type, where the briquettes are dried at a temperature of 150 ° C. Then the briquettes are poured into the cube, which is installed in the shaft furnace SShO-13.11 / 5-I2. Briquettes are sintered at a temperature of 250 ° C for 2 hours. The resulting briquettes from the charge are fed into the consumable hopper of the melting furnace. The furnace for the preparation of fluorophlogopite is made rotary, lined with graphite to protect the melt from impurities, with one arch electrode. The arch electrode is lowered to the bottom, and when it contacts the coke, an electric arc is ignited. 350 kg of briquettes are loaded into the oven. Under the influence of the heat of the electric arc, the melt of the briquetted charge begins. The melt, accumulating on the bottom of the furnace, forms a bath, and when it reaches a depth of 10-15 mm, the arc discharge goes out, and the current passing through the formed melt heats it due to the melt resistance. As the penetration is carried out, briquettes are loaded, not allowing the melt to open in the oven. The briquetted charge is melted at a temperature of 1650 ° C for 3 hours at the first melting and 1.5 hours at subsequent melts. When the melt is released from the furnace, subsequent briquettes are loaded in an amount of 300 kg. Melting the briquetted mixture in the furnace is a cyclic process that includes the main operations: start, periodic loading of the briquetted mixture, its melting and draining the melt into the ladle for casting. With an increase in the quantity (volume of the melt in the furnace) and an increase in its temperature, the electrode is gradually raised up, regulating the interelectrode distance by the melting process. At the same time, the current strength is increased. During the entire melting period, the electrode must be immersed in the melt. The duration of the heat at a useful power of 300-310 kW will be 3 hours. The result is a molten mica crystalline material based on fluoroflogopite receive the following composition, mass. % .: 41 silicon oxide, 11 alumina, 30 magnesium oxide, 9 potassium oxide, 9 fluorine. The molten mica-crystalline material based on fluorophlogopite is discharged from the furnace into a 500 kg kettle-type metal ladle and poured into casting molds, for example, into molds made of structural graphite grade 30PG (TU 48-20-86-81), or in sandy-clay molds . To eliminate layer-by-layer influxes, casting molds are heated to a temperature of 200 ° C before pouring the melt. Pouring is carried out by an even continuous stream at a melt temperature of 1450 ° C. The castings are kept in casting molds for 20 minutes, then removed from the casting molds and transported by a lifting-transport mechanism for annealing in a chamber furnace with a movable hearth type SDO-15.12.19 / 9-5. The annealing temperature is maintained at 920 ° C and at this temperature isothermal exposure is carried out for 2 hours, then the furnace is turned off and the castings begin to cool at a speed of 50 ° C / hour. Annealing in the furnace is carried out for 24 hours to a temperature of castings of 50 ° C. Then the castings are cleaned of sagging and burrs and sent to the consumer in accordance with the technical conditions for the castings.

Thus, pilot studies and production tests have shown that, with the optimal composition of mica-crystalline material, due to the physicochemical properties of the main mineral of fluorophlogopite and the dense fine-grained structure (especially surface layers) of the main mineral phase, fluorophlogopite products are obtained with a smooth and even surface. The outer casting surface, formed by very small variously oriented fluorophlogopite crystals bonded by a glass phase, is the most dense and durable part of the product, which determines its corrosion resistance under conditions of exposure to a high-temperature aggressive environment. On the working surface of the casting there are no cracks, sinks, mechanical damage. The content of the main mineral phase - fluorophlogopite - ranges from 75 to 92%, and the content of the glass phase does not exceed 2-3%. The size of the crystals does not exceed 5 mm, the porosity is 0.5-1%.

EFFECT: invention makes it possible to obtain mica-crystalline material based on fluoroflogopite with improved heat and corrosion resistant properties, which allows to increase the service life of equipment using castings from mica-crystalline material based on fluorophlogopite by 2-4 times. In addition, the proposed method for the production of mica crystalline material based on fluoroflogopite can improve the productivity of the installation.

Claims (9)

1. Mica crystalline material based on fluorophlogopite, including oxides of silicon, aluminum, magnesium, potassium and fluorine, characterized in that it contains the indicated ingredients in the following ratio, mass. %:
Silica 39.0-43.0 Aluminium oxide 9.0-12.0 Magnesium oxide 27.1-30.0 Potassium oxide 7.1-9.0 Fluorine 8.0-12.0 2. A method for the production of mica-crystalline material based on fluorophlogopite according to claim 1, including preparing the charge components, mixing, adding water to the mixture to obtain a plastic mass, its formation, drying, melting to obtain molten mica-crystalline material, pouring it into casting molds, holding for the production of castings, the extraction of castings from the molds and their annealing with gradual cooling, characterized in that the mixture is prepared from quartz sand, alumina, periclase powder and potassium silicofluoride, with the following ratio of components, mass. %:
Quartz sand 33.5-34.5 Alumina 9.5-10.5 Periclase powder 29.5-30.5 Potassium Silicon Fluoride 25.5-26.5
to obtain a plastic mass, a heated solution of lignosulfonates is used as a binder component, which is supplied simultaneously with water to the mixture with continuous stirring for 15-20 minutes to a mass moisture content of 3-8%, the plastic mass is formed in the form of briquettes and dried stepwise at first at a temperature 100-200 ° C, then at a temperature of 200-300 ° C for 2-3 hours, the briquettes are melted at a temperature of 1600-1750 ° C for 1.5-3.5 hours, the castings are annealed at a temperature of 910-950 ° C carrying out isothermal curing at this temperature ki for 1-3 hours and subsequent cooling rate of 30-60 ° C / hour. 3. The method according to p. 2, characterized in that the mixture is mixed for 15-30 minutes. 4. The method according to p. 2, characterized in that the lignosulfonate solution is heated to a temperature of 60-80 ° C. 5. The method according to p. 2, characterized in that the briquettes form a size of 20 × 50 mm 6. The method according to p. 2, characterized in that the molten mica-crystalline material is kept in casting molds for 15-30 minutes. 7. The method according to p. 2, characterized in that the molds before pouring the molten mica-crystalline material is heated to a temperature of 150-200 ° C. 8. The method according to p. 2, characterized in that the castings are annealed for 22-24 hours. 9. The method according to p. 2, characterized in that the castings are cooled to a temperature of 50-80 ° C.