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INVENTION
Patent of the Russian Federation RU2209859
METHOD FOR GROWING COLOR VARIETIES OF QUARTZ CRYSTALS
Name of the applicant: Federal State Unitary Enterprise "All-Russian Scientific and Research Institute of Synthesis of Mineral Raw Materials"
The name of the inventor: Dorogovin BA; Sopelyova EG; Mukhanova NG; Mareeva TV; Yevseeva IB; Maryin AA; Shishminov A.V.
The name of the patent holder: Federal State Unitary Enterprise "All-Russian Scientific and Research Institute of Synthesis of Mineral Raw Materials"
Address for correspondence: 601650, Vladimir Region, city of Alexandrov, ul. Institutskaya, 1, FSUE "VNIISIMS"
The effective date of the patent: 2002.07.24
The invention relates to the field of growing under hydrothermal conditions by the method of temperature drop of quartz and its varieties used in the jewelry industry as semi-precious stones. SUMMARY OF THE INVENTION: in a method for growing colored varieties of quartz crystals by a hydrothermal method involving putting the autoclave into a growth mode, performing its heating under the condition of hydrothermal etching of the seed plates and growth of the crystals on these seed plates at a crystallization temperature of 300-315 ° C. in an autoclave with a temperature difference between Growth and dissolution zones, the heating and hydrothermal etching of the seed plates are carried out at a temperature of 10-20 ° C above the crystallization temperature at the step of introducing the autoclave into the growth mode, after which the temperature is decreased from the steady-state temperature in the autoclave to a growth rate of 1.5-2, 0 o C / day with a simultaneous increase in the temperature drop from zero to growth at a rate of 3-5 o C / day, while observing in this case the constants of the average temperature and pressure. The invention makes it possible to improve the quality of the obtained color varieties of quartz crystals.
DESCRIPTION OF THE INVENTION
The invention relates to the cultivation of quartz and its varieties under hydrothermal conditions by the temperature drop method used in the jewelry industry as semi-precious stones.
A method for the preparation of citrine crystals is known (US Patent No. 4,024,013, IPC: B 01 J 17/04, C 01 B 33/12, 1974) based on seeding under hydrothermal conditions using a temperature difference between growth and dissolution zones, Created as a result of heating the autoclave. Crystals thus grown have defects due to the appearance of cracks, bundles in the overgrown layer coming from the surface of the seed plate.
The closest to the technical solution to the proposed invention is the method for the synthesis of stained quartz crystals (Hadzhi VE, Gordienko LA, Dorogovin BA, Zinober LI, Belimenko FA and Evseeva IB General principles and technical processes of hydrothermal synthesis of piezo-optical and colored quartz.// In the book "Synthesis of minerals", vol. 1, 2000, pp. 85-154) by the hydrothermal method, including the autoclave entering the growth regime, heating the autoclave and carrying out hydrothermal Seeding the seeds when heated before the growth process, growing crystals on these seeds at a crystallization temperature of not more than 315 ° C. in the presence of a temperature difference between the growth and dissolution zones. However, the colored varieties of quartz crystals obtained by this method are not of sufficiently high quality, namely: they have cracks, usually dissecting the entire accreted material and coming from the surface of the seed plate, contain "punctures" and capillary vacuoles.
The technical problem of the proposed invention is to improve the quality of the obtained color varieties of quartz crystals for use as raw materials for the jewelry industry.
The stated technical problem is solved due to the fact that in the method of growing colored varieties of quartz crystals by a hydrothermal method involving putting the autoclave into a growth mode, performing its heating under the condition of hydrothermal etching of the seed plates and growth of the crystals on these seed plates at a crystallization temperature of 300-315 ° C In an autoclave with a temperature difference between the growth and dissolution zones, heating and hydrothermal pickling of the seed plates are carried out at a temperature of 10-20 ° C above the crystallization temperature after the autoclave is introduced into the growth mode, after which the temperature is reduced from the steady-state autoclave to the growth rate 1.5-2.0 o C / day with a simultaneous increase in the temperature drop from zero to growth at a rate of 3-5 o C / day, while observing in this case the constants of the average temperature and pressure.
Distinguishing features of the claimed method are the conditions for introducing the autoclave into the growth mode, when the heating and hydrothermal etching of the seed plates is carried out to a temperature of 10-20 ° C. above the crystallization temperature, after which the yield on the growth regime is effected by lowering the crystallization temperature from the steady-state growth in the autoclave to the growth rate 1.5-2.0 o C / day with a simultaneous increase in the temperature drop from zero to growth at a rate of 3-5 o C / day, while observing in this case the constants of the average temperature and pressure. During heating of the autoclave and hydrothermal etching of the seed plates accompanying the heating process, up to a temperature of 10-20 ° C above the crystallization temperature, favorable conditions are created for dissolving the surface layer of the seed plates, where through the penetration channels, through the etching channels, which with the growth of the crystals for these seeding The plates are overgrown, which eliminates stress in the crystals and prevents the appearance of cracks. Heating the autoclave to a temperature above the crystallization temperature by less than 10 ° C lowers the efficiency of qualitative preparation of the seed plates, and by more than 20 ° C causes the complexity in making a smooth transition to the regime parameters of growth while maintaining a constant pressure. Optimal selection of the yield parameters for crystal growth parameters by lowering the temperature from the steady state in the autoclave after heating it to a growth rate at a rate of 1.5-2.0 ° C / day, with a simultaneous increase in the temperature difference between growth zones and dissolution from zero to growth At a speed of 3-5 o C / day, while maintaining a constant average temperature and pressure in this case, helps to reduce the defects at the boundary of the seed-growing layer and, thereby, ensures the fulfillment of the technical task - improving the quality of the grown crystals of colored quartz. The deviation of the rate of decrease in the crystallization temperature established in the autoclave during heating to growth, and the rate of increase in the temperature drop to growth upwards from the optimally established interval, leads to the formation of defects at the boundary of the primer - the overgrown layer, and the deviation to the smaller side slows the yield to Given crystallization parameters, making it difficult to start the process of crystal growth, and in addition, lengthens the growing process, which in itself is long, thereby making it economically impractical.
An example of a particular embodiment of the method
In a 1500 liter autoclave, the mine is buried in the form of natural veined quartz. At the top of the autoclave, the seed plates are suspended and the working solution containing 8% of potassium carbonate is poured into it. The autoclave filling ratio is 0.87. After that, the autoclave is sealed and injected into the growth mode by performing a heating of the seed plates accompanied by hydrothermal etching. The heating process and the hydrothermal etching of the plates are carried out to a temperature of 10-20 ° C above the crystallization temperature of 310 ° C. The growth regimes are then carried out, reducing the temperature from the steady-state autoclave during heating and being the end of hydrothermal etching of the seed plates, 310 ° C at a rate of 1.5-2.0 ° C / day, and simultaneously increase the temperature difference between the growth and dissolution zones from zero to growth-31 ° C at a rate of 3-5 ° C / day. The average temperature and pressure in this case remain constant. After that, hydrothermal synthesis of colored varieties of quartz crystals is carried out. The crystallization temperature is 310 ° C, the pressure is 1235 atm, and the temperature difference between the growth and dissolution zones is 31 ° C. As a result, we obtain high quality quartz crystals.
The results of the experiments are tabulated
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The use of the proposed method for the synthesis of color varieties of quartz crystals allows to grow high-quality colored quartz crystals for the jewelry industry with an output of 80-95% without cracks and delaminations in the overgrown layer.
CLAIM
The method of growing colored varieties of quartz crystals by the hydrothermal method, including putting the autoclave into a growth mode, performing its heating under the condition of hydrothermal etching of the seed plates and growth of the crystals on these seed plates at a crystallization temperature of 300-315 ° C in an autoclave with a temperature difference between growth zones and dissolution , Characterized in that during the step of introducing the autoclave into the growth mode, heating and hydrothermal etching of the seed plates is carried out to a temperature of 10-20 ° C. above the crystallization temperature, after which the yield to the growth mode is carried out by lowering the temperature from the steady-state growth in the autoclave to a growth rate of 1, 5-2.0 o C / day with a simultaneous increase in the temperature drop from zero to growth at a rate of 3-5 o C / day, while observing in this case the constants of the average temperature and pressure.
print version
Date of publication 03.01.2007gg
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