RU1834921C - Method for preparing coloured quartz crystals - Google Patents

Abstract

Use: for jewelry purposes. The essence of the invention: when growing quartz crystalloe by the hydrothermal method, an oxidizing agent consisting of gallium nitrate (10-50 mg / l) m nitric iron was added to the seed in an aqueous solution of potassium carbonate with iron impurities

Description

The invention relates to the field of growing single crystals, in particular colored quartz, and is industrially applicable for jewelry purposes.

An object of the invention is to increase the jewelry value of colored quartz crystals by expanding the gamut of colors.

This goal is achieved by the fact that in the known method for producing colored quartz crystals by the hydrothermal method from an aqueous solution of potassium carbonate containing an oxidizing agent and impurities of iron for seed, gallium nitrate in an amount of 10 to 50 mg / l and iron nitrate are used as an oxidizing agent. amount from 0.5 to 1.5 g / l.

In particular, in order to obtain amethyst, the crystals are grown on a seed parallel to the face of the small rhombohedron. In order to enhance color saturation, the solution may further comprise cobalt oxide and lithium nitrate.

In particular, in order to obtain citrine, crystals are grown on a pinacoid steroid and then irradiated with a dose of 10b to 107P.

As is known, when grown in alkaline media, gallium impurities do not enter the crystal structure, since gallium forms an insoluble silicate fzu in them.

memory K GaSiaOs and removed from the rastaora. The introduction of iron nitrate, as well as gzlli and lithium nitrate into the solution creates a strong oxidizing environment (MOH) -. which allows Ga + ions to enter the crystal and replace Si +, and after γ-irradiation with a dose of 10 (at lower doses, color centers are not created) to 10 (color saturation occurs at this dose) to form yellow centers. When grown on seeds parallel to the faces of the small rhombohedron, Fe ions entering the crystal form centers of violet color, and when grown on a pinacoid seed, they form centers of yellow color. In the first case, the simultaneous presence of centers of violet and yellow color allows to obtain red-violet a shade that brings the crystal closer to the best varieties of natural amethyst in jewelry value. In the second case, two types of centers of yellow color are simultaneously present. The hue in both cases can be varied by changing the concentration of gallium in the solution and the dose of radiation.

A decrease in the concentration of Fe (MOH) h of less than 0.5 g / L reduces the oxidation potential of the solution, which leads to the formation of the above-insoluble silicate phase and Ga is removed from the solution. An increase in the concentration of iron nitrate above 1.5 g / L causes the saturation of Ga3 + to be difficult due to the intensive entry of iron into the crystal. When the concentration of Ca (MO3) s is less than 10 mg / L, the influence of the centers of yellow color becomes hardly noticeable, and when the concentration of gallium nitrate exceeds 50 mg / L, yellowness in the color begins to appear in amethyst crystals, and the effect of centers in the crystals of citrine becomes invisible yellow color formed by Fe ions.

The introduction of iron in the form of nitric acid leads to the fact that it enters the crystal in the form of Fe ions uniformly throughout the entire growth cycle, since its concentration in the solution is several orders of magnitude higher than in the growing crystal.

Obtaining crystals of colored quartz is possible at concentrations:

K2CO3-from 5 to 10%, Co 20 zot 10 to 200 mg / l, LINOj from 0.01 to 0.05%. Growing conditions: temperature from 250 to 400 ° C, temperature difference from 20 to 40 ° C, pressure from 40 to

160 MPa. After growing, the crystals were treated with ionizing γ-radiation (source SobO, dose 106 to 107 R).

Example 1. Amethyst crystals were grown in a standard autoclave with a capacity of 500 ml using the hydrothermal method for seeds, parallel to the faces of the small rhombohedron, at a crystallization temperature of 341 ° C, a temperature drop of 28.5 ° C, a pressure of 115 MPa, a working solution;

7% KZsoz; 1.2% Re (MOH) s; 20 mg / l Co203; 0.02% SHOz; 20 mg / l 6z (MOH) s. As a result, amethyst crystals of a uniform, pinkish-violet color with a density of 1, were obtained. Other examples are given.

in table 1,

Example 2. In a standard autoclave with a capacity of 500 ml at a temperature of 324 ° C, a temperature difference of 29 ° C, a pressure of 60 MPa in an 8% solution of K2COz with additives

Re (MO3) s in an amount of 0.5 g / L and Ca (MO3) s in an amount of 30 mg / L were obtained crystals of cytpin, which after irradiation with a dose of SR had a bright yellow color with a density of 0.4. Other examples

are given in table 2.

Claims (3)

1. The method of obtaining colored quartz crystals, including their growing hydrothermally from an aqueous solution of potassium carbonate containing impurities of iron and an oxidizing agent, for seed and subsequent γ-irradiation, characterized in that as an oxidizing agent iron nitrate and nitrate are used in an amount of 10-50 mg / l and 0.5-1.5 g / l, respectively. 2. The method of pop. 1, characterized in that to obtain amethyst color the seed is taken parallel to the face of the small rhombohedron, and the solution additionally contains cobalt oxide and lithium nitrate. 3. A method according to claim 1, characterized in that a pinacoid seed is used to obtain a color of citrine, and the radiation is carried out at a dose of 106-10 P. Table 1 table 2