JPS6081084A - Synthesis of single crystal of artificial beryl - Google Patents

Abstract

PURPOSE:To synthesize single crystal of beryl of good quality economically with high efficiency by charging salts corresponding to the specified compositional ratio of beryl to a vessel separated into three chambers with baffle plates and producing temp. difference in each chamber. CONSTITUTION:Lithium molybdate, molybdenum trioxide, and vanadium pentoxide, as flux, are added to starting materials comprising beryllium oxide, aluminum oxide, and silicon dioxide having almost equal compositional ratio to beryl, with, if necessary, coloring material such as chromium oxide, and the mixture is heated to above the melting temp. of the flux. At least one kind among the above described starting materials is sintered or vitrified previously and added to the molten salts in the vessel separated into three chambers by baffle plates. Single crystal of beryl is thus synthesized or grown by producing temp. difference between each chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method (molten salt method) for synthesizing an artificial beryl single crystal (hexagonal system) using a solvent (flux).

[Prior art]

The molten salt method uses c heat of energy compared to the hydrothermal method.

This method is advantageous in that the pressure (pressure) and growth period are short, and the equipment and parts used can be greatly simplified, making it economical. In other words, the molten salt method uses beryllium oxide, aluminum oxide, silicon dioxide, and optionally chromium oxide (this is an essential coloring agent that becomes the base color of emerald green when obtaining emerald), which shows the beryl composition ratio. A solvent such as vanadium pentoxide, molybdenum trioxide, lithium molybdate, lithium hydroxide, etc. is added to the raw material consisting of nickel oxide, iron oxide, cobalt oxide, manganese oxide, and other auxiliary colorants or doping agents. Add one or more selected from the above, heat the mixture to a temperature higher than the melting temperature of the solvent to form a molten salt, and hold the molten salt for a long period of time with a temperature difference. This is a method in which beryl seed crystals are placed in a molten salt by holding for a certain period of time and then slowly cooling with a gentle temperature gradient, thereby producing or growing everyl around the seed crystals.

[Purpose of the invention]

An object of the present invention is to efficiently and economically synthesize high-quality beryl single crystals by controlling the crystal growth speed.

Beryl single crystals synthesized by conventional methods tend to contain microcrystals such as feather inclusions and zenasite during the growth process, which reduces appearance quality and yield.

In order to prevent the generation of microcrystals such as feather inclusions and zenasite, the current gastric acid method (how to use raw materials, how to control temperature, etc.) must be carefully controlled and the speed of crystal growth must be controlled. However, the current method was insufficient.

[Summary of the invention]

In particular, in order to control the crystal growth speed, the present invention uses raw materials that have been vitrified or sintered in advance (beryllium oxide, aluminum oxide, silicon dioxide, chromium oxide as a coloring agent, etc.) and quartz, and also uses a crucible. The inside is divided into 3 sections with a nokusoful, a seed crystal growth zone (2 locations), a raw material 2 quartz melting zone (1 location), and the amount of melting is controlled by controlling the temperature of each zone. This method is characterized in that it also controls the amount of raw materials transported to the seed crystal zone.

Example 1 ill raw material beryllium oxide 4.1 r, aluminum oxide 5.5
y, weigh 0.39 chromium oxide to prepare a mixed powder.

Next, this mixed powder is mixed and pulverized in a ball mill for 5 hours or more, and the material of the bot and ball is a sintered material of high-purity alumina. Next, this mixed powder was compacted into a spherical shape, and the silicon dioxide to be sintered was prepared by cutting 52 pieces of quartz. Thereafter, add at a rate of 22 per week.

121 solvent Next, as a flux, powders of lithium molybdate, molybdenum trioxide, and vanadium pentoxide were added in a ratio of 1:2:'
Weigh and mix 4001 at a ratio of 7.

[3) Equipment A platinum crucible was used as a container for charging the above substances.

For heating, the apparatus shown in FIG. 1 was used. ■ is a heating device,
■ is a heating heater, and ■ is a thermocouple temperature measuring terminal that controls the heater.The temperature is controlled for each heater. ■ is a panful that partitions the inside of the crucible.

(4) Method: Put the solvent powder into a platinum crucible and set the temperature of the heating device to 950.
Set to ℃ and dissolve. Next, place the sintered body (
Beryllium oxide, aluminum oxide, chromium oxide) are added, and quartz pieces are added to the top. Next, set the temperature of the heating device at 9 in the seed crystal growth zone (2 places, ■ and O).
20°C, raw material 2 quartz zone (■) 950°C is changed.

When it is in the growing state, put seed crystals into the ■ and ■ zones. The surfaces of the parent and child crystals used are finished with poly.

[51] As a result, the seed crystal growth speed could be kept constant for a long time, and the occurrence of inclusions in the grown beryl single crystals could be extremely reduced.Also, very beautiful green (emerald green) crystals could be produced. Obtained.

<Example 2> Same as Example 1 12) As a solvent flux, powders of lithium molybdate, molybdenum trioxide, and vanadium pentoxide were weighed and mixed in a total ratio of 1:326.

[3) Apparatus Same as Example 1 [4) Method Same as Example 1 (5) Results The seed crystal growth speed can be kept constant for a long time, and the occurrence of inclusions in the grown beryl single crystal is extremely reduced. We were able to. Also, very beautiful green (emerald green) crystals were obtained.

<Example 3> Same as in Example 1 for il+raw material (2) As a solvent flux, 4002 powders of lithium molybdate, molybdenum trioxide, and vanadium pentoxide are weighed and mixed in a ratio of 1=1=8.

(3) Apparatus Same as Example 1 (4) Method Same as Example 1 (5) Result The seed crystal growth speed can be maintained constant for a long period of time, and the occurrence of inclusions in the grown beryl crystals can be extremely reduced. Ta. Very beautiful green (emerald green) crystals were obtained.

〔Effect of the invention〕

As explained in the examples above, the effects of the present invention are that, while securing the essential benefits of the conventional molten salt method, it is possible to improve quality and yield, resulting in a significant cost reduction. The present invention is extremely useful as a method for synthesizing artificial beryl single crystals.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an overview of the heating device according to the present invention, and FIG. 1 [αl shows a top view of the device, and FIG. ■ is the heating device, ■ is the lid of the heating device, ■ is the heater, ■ is the measurement terminal of the thermocouple thermometer, ■ is the seed crystal, ■ is the raw material, silica, ■ is the seed crystal growth zone, ■ is the raw material Material, quartz zone, ■ is seed crystal growth zone, O is platinum crucible, ■ is thermocouple terminal for molten salt measurement,
■ is a baffle. Applicant: Shuwa Seikosha Co., Ltd. Agent: Patent Attorney Mogami

Claims (1)

[Claims] A raw material consisting of beryllium oxide, aluminum oxide, silicon dioxide and, if necessary, chromium oxide and other coloring agents having a beryl composition ratio, lithium molybdate, molybdenum trioxide, lithium hydroxide as a solvent,
In the method of synthesizing or growing an artificial beryl single crystal by adding one or more selected from vanadium pentoxide, etc. and heating it above the melting temperature of the solvent to form a molten salt, A baffle is created by pre-sintering or vitrifying one or more of the above raw materials in a molten salt that is a powder mixture of three solvents: lithium molybdate, molybdenum trioxide, and vanadium pentoxide. By placing the beryl single crystal in a container divided into three parts and creating a temperature difference, artificial beryl single crystals were produced using the method. synthesis method.