RU2788077C1 - Amber processing method - Google Patents

Abstract

FIELD: amber processing.

SUBSTANCE: invention relates to the processing of amber and can be used in the manufacture of jewelry or technical items. The method includes gradual heating of amber in an inert nitrogen gas environment at a pressure of 2.5-2.8 MPa for at least 1.5 hours to a temperature of 180-200°C. Exposure is carried out for 10-36 hours and gradual cooling is provided for at least 4 hours. The ratio of the volume of nitrogen and the volume of amber in the container is taken as 2:8.

EFFECT: increasing the translucency of amber.

1 cl, 1 tbl, 2 ex

Description

The invention relates to the processing of amber, and in particular to methods for increasing the translucency of amber and can be used in the manufacture of jewelry or technical products.

A known method of artistic processing of amber and a device for its implementation, including heat treatment in air, holding at a given temperature and subsequent cooling (AS No. 856822, B28D 5/00, publ. 23.08.1981, BI No. 31).

However, the known method does not provide the required quality of amber clarification, some of the blanks are not completely clarified, and, in addition, the surface of the amber blanks after this process is oxidized and has a dark color (mainly shades of red), which makes it difficult to work with the stone.

The closest analogue is the method of processing amber (A.S. No. 1039726 B28D 5/00, publ. 07.09.1983, BI No. 33) including heating amber in a gaseous inert atmosphere of nitrogen to 130-170 ° C and a pressure of 15-20 kgf/cm ² , exposure at a given temperature for 6-12 hours and subsequent cooling.

When using this method, it is not possible to achieve full translucency of all amber in the processed batch; as a rule, pieces of amber in shape close to spherical do not increase the translucency well. Such blanks have a small opaque area of spherical or ellipsoid shape inside the piece. As tests have shown, such pieces of amber are not subject to re-processing, because. they lose some of their useful technological qualities, become brittle, which limits their use in the jewelry industry.

The invention solves the problem of creating a more efficient way to increase the translucency of amber without deteriorating its technological qualities by changing the processing parameters of amber and choosing the optimal ratio of the volume of processed amber and the volume of inert gas.

To obtain the necessary technical result in the method of processing amber, including heating amber in an inert nitrogen gas environment under pressure, holding at a given temperature and pressure, followed by cooling, it is proposed to heat the amber gradually at a pressure of 2.5-2.8 MPa for at least 1.5 h to a temperature of 180-200°C, hold for 10-36 h2 and ensure gradual cooling for at least 4 h. In addition, the ratio of the volume of nitrogen and the volume of amber in the container is proposed to be taken as 2:8.

Before processing, amber is sorted into fractions according to size (see the table below) into several batches. This is necessary because Different sizes of amber pieces require different processing modes. A small stone is clarified much faster than a large one, due to the fact that a small stone, due to its small size, warms up to the entire volume faster and water vapor forms in the center of the stone faster. At the same time, a small stone has a smaller distance from the center to the periphery of the stone, and, consequently, it takes less time for water vapor to travel this small distance compared to a large stone.

When processing amber, an inert gas, such as nitrogen, is used. This is necessary because otherwise, the surface of the amber blanks after this process is oxidized and has a dark color (mostly shades of red), which makes subsequent work with the stone difficult.

Loading amber into the autoclave is carried out, maintaining the ratio of the volume of the inert nitrogen gas and the volume of amber, not more than 2:8. This is necessary because clarification occurs due to the saturation of the inert gas with water vapor. If the amount of gas is not enough, then at some point in the clarification process, a situation will occur that the gas will be maximally saturated with water vapor, but the process of water vapor release from the stone will not be completed yet, while some of the water vapor will remain in the stone, and this will lead to to the under-lightening of amber. Therefore, the volume of gas must be such that it is guaranteed to ensure the absorption of all water vapor released from the stone. As established by experience, the optimal ratio of the volume of inert gas and the volume of amber is not more than 2:8. The use of ratios below 2:8 is not advisable, because will lead to underloading of the autoclave, i.e. to a decrease in its productivity and to an increase in the consumption of inert nitrogen gas.

Amber is heated in an inert nitrogen gas medium, maintained at a given temperature and cooled, and the working pressure of the inert gas is 2.5-2.8 MPa. Heating of amber until it reaches the set temperature is carried out gradually for at least 1.5 hours, holding is carried out at a temperature of 180-200 ° C for 10-26 hours (depending on the size of the amber), the temperature is lowered to ambient temperature gradually over not less than 4 hours. Pressure and temperature are selected in such a way that at a given pressure the temperature is several tens of degrees below the boiling point of water. At this temperature, vaporization occurs quite intensively, but water does not boil. Boiling water in the pores of amber at high temperature and pressure leads to the appearance of cracks and cavities inside a piece of amber. The time of heating and cooling was selected empirically so that during heating and cooling cracks did not form in a piece of amber. The exposure time at a given temperature was selected empirically, taking into account the provision of 100% translucency of all pieces of amber in the processed batch, while there is no need to increase the time, because. this increases the time of the technological process, but does not improve the appearance of amber. When choosing a shorter exposure time, the presence of underclarified pieces of amber was observed, the translucency of which was below 100%.

Suggested processing parameters for amber are given in the table.

A specific example of the proposed method for processing amber.

Example 1

We took matte amber fractions weighing up to 10 g in a volume of 8 liters using an autoclave with a working chamber volume of 10 liters. The autoclave was filled with an inert nitrogen gas. The autoclave was turned on. Heating to a temperature of 180°C was carried out for 1.5 hours. Exposure at a given temperature and pressure of 2.5 MPa was carried out for 10 hours. Cooling was carried out for 4 hours.

Result: no matte areas in the entire batch of amber, 100% translucency, no cracks and oxidation of the surfaces of the pieces of amber in the entire batch.

Example 2

We took matte amber fraction weighing 30-80 g in a volume of 8 liters using an autoclave with a working chamber volume of 10 liters. The autoclave was filled with an inert nitrogen gas. The autoclave was turned on. Heating to a temperature of 190°C was carried out for 1.5 hours. Exposure at a given temperature and pressure of 2.6 MPa was carried out for 16 hours. Cooling was carried out for 4 hours.

Result: 100% translucency, without cracks and oxidation of the surfaces of amber pieces in the entire batch.

Claims (1)

A method for processing amber, including heating amber in an inert nitrogen gas environment under pressure, holding at a given temperature and pressure, followed by cooling, characterized in that the heating of amber is carried out gradually at a pressure of 2.5-2.8 MPa for at least 1.5 h to a temperature of 180-200°C, kept for 10-36 h and provide gradual cooling for at least 4 h, in addition, the ratio of the volume of nitrogen and the volume of amber in the container is taken as 2:8.