JPS646159B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing quartz, which is a refractory oxide, by utilizing a room temperature concentration phenomenon.

Quartz has a wide range of uses, including abrasive materials, watch bearings, jewelry, and record needles. Conventional methods for obtaining single crystals of refractory oxides include the pulling method, EFG method,
Known methods include the heat exchange method, Bakdazarov method, Bernoulli method, and flux method. ~
In both methods, raw materials are placed in a crucible or container, heated to high temperatures, melted, and grown under seed crystals. It is the same as ~ in that it does not use a crucible or container, but the raw materials are melted at high temperatures. This is a method in which raw materials are melted at a temperature lower than their melting point using a fluxing agent PbO or quartzite (Na ₃ AlF ₆ ) to crystallize crystals. In either method, it is necessary to raise the temperature to at least 1000°C or higher, and therefore a high melting point metal such as platinum, iridium, or molybdenum must be used as the crucible or melter. In addition, special materials are used for high-temperature melting furnaces and heating elements.
Equipment required.

The present invention provides a method for easily producing crystal using a room-temperature concentration phenomenon without using complicated and expensive equipment.

The method of this invention involves mixing a solution containing iron (Fe) and a solution containing silicon dioxide (SiO ₂ ), and adding seed crystals to this mixed solution and leaving it to stand.
It is characterized by growing crystals through a room-temperature concentration phenomenon.

For example, when a solution prepared by dissolving Fe in 4-12 nitric acid and an aqueous solution of silicate or silica gel are mixed and left to stand, crystals will crystallize in the gel-like substance containing SiO ₂ produced in the solution. . It is thought that Fe(OH) ₃ or SiO ₂ gel in the solution acts as a catalyst for this crystal growth.

The basic advantage of the method of this invention is that it does not require high temperatures unlike conventional methods and can be easily carried out at around room temperature. The size and growth rate of the crystals obtained are controlled by controlling the pH concentration, temperature, degree of supersaturation, etc. of the solution, and by adding seed crystals.

Examples of the present invention will be described below. Two 100 c.c. beakers were prepared, approximately 50 c.c. of 8N nitric acid was placed in one beaker, and an iron rod (2 mmφ x 30 mm) containing trivalent Fe was placed in the beaker. Furthermore, approximately 5 c.c. of NaOH was added to adjust the pH concentration. Pour 50 c.c. of water into the other beaker and dissolve the silica gel in it.
A silica solution with a SiO ₂ concentration of 50 ppm was prepared. These solutions were mixed little by little alternately and finally all were put into one beaker, quartz seed crystals were added thereto, and the mixture was left for 5 days. As a result, quartz crystals were generated on the seed crystals. Furthermore, in the above example
Although nitric acid was used to dissolve Fe, a mixture of nitric acid and other acids may also be used. Furthermore, regarding solutions containing SiO ₂ , Na ₂ SiO ₃ , K ₂ SiO ₃ , Fe
An aqueous solution of silicate can be used that produces a SiO ₂ gel when mixed with a solution containing silicates.

The effects of this invention are listed below. (1) Quartz crystals, which conventionally could only be grown at high temperatures of at least 1000°C, can be produced extremely easily at room temperature. (2) Complex and expensive devices and equipment such as heat-resistant containers and high-temperature melting equipment are not required, and therefore inexpensive crystal can be provided. (3) Crystal growth can be performed on seed crystals, and epitaxial growth of crystals is also possible by controlling the pH concentration of the solution.

Claims (1)

[Scope of Claims] 1. A method for producing crystals, which comprises mixing a solution containing iron and a solution containing silicon dioxide, adding seed crystals to the mixed solution, and leaving the mixture at room temperature to precipitate crystals. 2. Production of crystal according to claim 1, wherein the iron-containing solution is a solution in which iron is dissolved in 4-12 standard nitric acid, and the silicon dioxide-containing solution is a solution in which nitrate or silica gel is dissolved in water. Method.