JPS58115094A - Synthesis of artificial beryl single crystal - Google Patents

Abstract

PURPOSE:To prepare a high-quality single crystal free from inclusion, in high efficiency, in the titled synthesis using a molten salt, by purifying the flux and/ or the raw materials with heat-treatment. CONSTITUTION:Flux of flux and a raw material of beryl are heated at about 1,000-1,400 deg.C for about 15hr, and quenched to about 500-650 deg.C. The impurity which is a main cause of inclusion can be removed by this treatment. The molten salt (flux) quenched to the specified temperature is transferred to another crucible containing the raw material of beryl, heated at a specific temperature, and charged with a seed crystal to effect the growth of beryl. A high-quality beryl single crystal can be prepared by this process.

Description

[Detailed Description of the Invention] The present invention relates to a method for synthesizing artificial beryl single crystals using a bath agent (flux), and relates to a method for efficiently and economically synthesizing high-quality beryl single crystals by a molten salt method. .

Hydrothermal methods and molten salt methods using solvents have been known as conventional methods for synthesizing artificial beryl, but the present invention relates to improvements in the molten salt methods.

The molten salt method can be said to be considerably more economical than the hydrothermal method in that it requires less energy and growth time, and uses relatively simple equipment. That is, in the molten salt method, a bath agent such as molybdate, vanadium pentoxide, tungstate, etc. is added to a raw material consisting of berylum oxide aluminum oxide, silicon dioxide, and, if necessary, a coloring agent such as chromium oxide, which has a beryl composition ratio. Add one or more solvents selected from the above solvents, heat this to a temperature higher than the melting temperature of the above solvent to form a bath molten salt, and maintain this bath molten salt at a constant temperature for a long time or at a constant gradient. This is a method of producing or growing artificial beryl in a molten salt bath by cooling it with water. This type of molten salt method usually only requires heating and holding within the range of 700°C to 1400°C, so the equipment is simple, compared to the hydrothermal method, which uses a complicated autoclave and grows under high temperature and high pressure. , which is synthetically advantageous. However, this molten salt method also has the following problems.

The amount of 4 rill produced, which results in a product with high purity, is small relative to the amount of raw material used in one batch. That is, according to the conventional method, inclusions are likely to occur in the beryl generated and grown around the seed crystal, making it difficult to obtain a high-quality beryl single crystal.

The present invention solves this problem by removing impurities, which are the main cause of inclusions, through heat treatment by heating and cooling.

The present invention focuses on removing inclusions by removing six impurities and substances in molten salt (7 sixes), and heats the molten salt to 1000°C to 1400°C by adding beryl composition siflux alone or flux and raw materials. Hold for 15 hours and rapidly cool 7 to 500°C to 650°C. The molten salt, which has reached a predetermined temperature, is poured into another crucible containing raw materials. #
! i Create a crucible containing salt and raw materials and grow at a temperature of 800.
, 'E ~ 1200 ° C. After reheating in a trench, it is held. After that, the seed crystals are obtained. An example of this is given below.

Example 1 ■ Ability to correspond to drawings - Bum■ Raw materials, solvents, and K blended natural beryl powder Hl f LSmMo'n 55F M, o 559Crm
Os 0.1F ■ Temperature for forming molten salt ■ Fill material into platinum crucible and hold at 1400'CK for 15 hours ■ Cool and heat and hold, then rapidly cool to 500℃ at room temperature ■ Heat again to 900℃ for 1 hour Heating ■ Treatment after reheating 2 hours after the temperature reached 900°C, seed crystals were added and left in the kernel state for one month ■ Results and observations Yield of emerald single crystals Almost no 5- to 7-inch inclusions were found.

Example 2 ■ Ability to correspond to drawings - Pum ■ Same as ■ of Example 1 ■ Temperature conditions for forming molten salt Fill a platinum crucible with Kl molten salt and hold at 400°C for 15 hours ■ Same as ■■ Same as ■ of Example 1■ Injecting 7 lacs into the crucible Heating the 7 lacs to 900℃, pouring the flux into the crucible filled with raw materials.The crucible with the flux added has a furnace temperature of 900℃. Leave it inside.

■ Insertion of seed crystals: 5 hours Insertion of cypress crystals L2 - 900 tons in the evening: Leave for 5 hours.

■ Results and findings Emerald yield: 3-5 chi Inclusions are almost never seen.

Example 3 ■ Curve B corresponding to the drawing ■ Same as ■ in Example 1 ■ Temperature conditions for forming molten salt ■ Fill material into a platinum crucible and hold at 100 OC for 15 hours ■ After cooling and heating, hold at room temperature to 650 °C Rapid cooling ■ Reheating to 900℃ for 1 hour ■ Treatment after reheating 2 hours after reaching 900℃ Add seed crystals and in this state
I left it for a month.

■ Results and findings Emerald single crystal yield 3-7% Inclusions are almost never seen.

In the above-described embodiments, the present invention solves the problem of inclusions in artificial single crystals, so that higher quality and higher yield can be obtained than in the conventional method.

Although high-quality natural beryl powder was used as the raw material in the illustrated embodiment, the same results could be obtained by using high-purity perylum oxide, aluminum oxide, or silicon oxide instead.

According to the above explanation and examples, according to the present invention, the essential benefits of the conventional molten salt method are retained by adding a simple thermal operation to the conventional molten salt method for synthesizing artificial beryl single crystals. In addition, the present invention is extremely meaningful as a method for synthesizing artificial beryl single crystals, since it contributes to improved quality and yield and reduces costs.

[Brief explanation of drawings]

FIG. 1 shows the temperature-hour characteristic of a bath molten salt based on an example of the present invention. Applicant Matsushima Kogyo Co., Ltd. Naiwa Seikosha Co., Ltd. Agent Tsutomu Mogami, Patent Attorney Figure 1

Claims (1)

[Claims] PeriJ oxide showing the composition ratio of Haboberyl A raw material made by adding coloring agents such as aluminum oxide, silicon dioxide, and chromium oxide, as well as nonazine pentoxide and monopden as a flux. In the method of synthesizing or growing an artificial beryl single crystal by adding one or more selected acids, tungstic acid, and heating to a temperature higher than the melting temperature of the bath agent to form a bath molten salt, a single flux is used. Alternatively, a method for synthesizing an artificial beryl single crystal by a molten salt method, which is characterized in that a slack and a raw material are heated and rapidly cooled to perform a purification treatment.