RU2716692C1 - Method of extracting diamonds from a tool matrix - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to extraction of diamonds from diamond-bearing tool matrix. Method involves dissolving binding metal with electrolyte to form sludge containing diamond particles, separating electrolyte from slurry and recovering diamonds, wherein bonding metal is dissolved in sulfuric acid solution with concentration of 100–300 g/l with activating additives: nitric acid or ammonium nitrate, and extraction and classification of diamonds is carried out in an ascending flow with variable hydrodynamic mode at linear speed within 15–45 m/h. Concentration of nitric acid or ammonium nitrate is varied within 20–50 g/l, and process of dissolution is carried out at temperature of 60–80 °C.

EFFECT: technical result consists in expansion of technical capabilities in selection of structural materials and elimination of losses of diamonds and valuable matrix components.

1 cl, 2 dwg, 1 tbl, 3 ex

Description

The invention relates to methods for extracting diamonds from diamond-containing materials, which may be products of diamond synthesis, waste products from synthesis products, and can be used in enterprises producing synthetic diamonds or specializing in the processing of diamond synthesis products.

A known method for the extraction of diamonds from diamond-containing material, including the dissolution of metals with concentrated acids (in particular hydrochloric acid), followed by the oxidation of graphite in the presence of nitrous acid ammonium and metal oxides of lead, manganese and zinc and processing of the product with hydrochloric acid. [: US Patent N 4578260, C01B 31/06, 1986.]

The disadvantage of this method is the use of concentrated acids and toxic oxidizing agents and, as a consequence, the need for wastewater treatment, harmful working conditions, environmental pollution, loss of diamonds due to the need for a large number of washes after acid treatment.

The method is recognized as more perfect [RF Pat. No. 2043299, C01B 31/06, application. 501486/26, 10.30.1991, publ. 09/10/1995] the extraction of diamonds from diamond-containing material, including the removal of metals and separation of graphite from diamond, characterized in that the product obtained after removal of metals is calcined at 300-700 ° C for 10-300 minutes, and graphite is separated from diamond by flotation. The method is time consuming, requires significant energy costs and does not exclude the use of concentrated acids in the initial stages of metal removal.

The closest recognized method for the extraction of diamonds and carbide components from a diamond matrix tool [RF Pat. No. 2062252, C01B 31/06 application., 89 4771371 12/18/1989 Convention. prior December 18, 1989], including disintegration of the matrix by electrolytic dissolution of the metal binder with the formation of sludge from particles of diamonds and carbide components, separation of the electrolyte from the sludge, drying of the sludge and separation of diamonds and carbide components, characterized in that, in order to increase the yield of extracted diamonds and improve their quality, after separation of the electrolyte before drying, the sludge is further disintegrated and diamond grains are cleaned by treatment in an aqueous solution of hydrochloric acid and then in aqueous astvore alkali and, after drying and isolation of the diamond and cemented carbide components is ground isolated diamonds electrohydraulic crushing, conditioning isolated shaped diamonds, the remaining level ovalizuyut conditioned in form and those of other isolated and conditioning strength diamonds. At the same time, the remaining diamonds of substandard strength are divided into two batches of grain size up to 1 mm and more than 1 mm and processed by electro-hydraulic crushing and volumetric compression, respectively, followed by the release of conditionally shaped diamonds.

The last of the above is also not without drawbacks, the main of which are: restrictions on the choice of structural materials when using hydrochloric acid, the inevitable loss of part of the conditioned grains in the electro-hydraulic crushing mode at the finishing stage.

The solved problem of the claimed invention is the expansion of technical capabilities in the selection of structural materials, the exclusion of loss of diamonds and valuable matrix components.

The essence of the claimed technical solution lies in the fact that the extraction of diamonds from the diamond matrix of the tool, including the dissolution of the metal binder by an electrolyte with the formation of a sludge containing diamond particles, the separation of the electrolyte from the sludge and the selection of diamonds, characterized in that the dissolution of the metal binder is carried out in a sulfuric solution acids with a concentration of 100-300 g / l with activating additives: nitric acid or ammonium nitrate, and the selection and classification of diamonds is carried out in an upward flow with a variable guide odinamicheskim mode at a linear velocity in the range of 15-45 m / h.

The concentration of nitric acid or ammonium nitrate varies in the range of 20-50 g / l, and the dissolution process is carried out at a temperature of 60-80 ° C.

The achieved results of the proposed method are based primarily on the fact that the matrix base of a diamond tool usually contains copper, cobalt, nickel in a wide variety of proportions and solder elements: lead, tin. It was experimentally established that the removal of metals can be achieved by their conversion to a solution of sulfuric acid at a relatively low concentration in the presence of activators of the dissolution process in the form of nitrates. Solder elements in this case, in particular lead, form poorly soluble sulfates. The slurry after separation of the solution is a multiphase system of diamonds in their original form with finely dispersed sulfates of solder and graphite elements. The use of an ascending flow with a variable hydrodynamic regime allows you to simultaneously wash diamonds from an acid solution, separate the sulfate-graphite component and, if necessary, classify diamonds by size and perfect shape.

The essence of the method is illustrated by examples.

Example 1. Diamonds were extracted from a batch of spent drill columns, the diamond layer of which contained the following components in weight percent: diamonds in the form of grains with a grain size of 400 to 800 μm-8, the base metal (alloy of copper, nickel, cobalt) - 62, solder and impurities rest. The dissolution of the base was carried out by immersion of the samples under a layer of a solution of sulfuric acid with a concentration of 100-300 g / l. The dissolution rate was regulated by the introduction of nitrate ion in the form of nitric acid. The process temperature was maintained at 60-80 ° C. After disintegration of the sample base due to dissolution, the solution was decanted, and the sludge residue was used as the feed for the laboratory pulsation column, the scheme of which is shown in FIG. 1, where 1 is a pulsation column with a packet nozzle of the KRIMZ type, 2 is a conical sump, 3 is a circulation pump, 4 is a membrane pulsator.

Example 2 Difference from the procedure described in example 1, the dissolution rate was regulated by the introduction of ion nitrate in the form of ammonium nitrate. The advantage of this mode is that the gaseous reaction products are not represented by nitrogen oxides, but mainly by molecular nitrogen. Eliminates harmful effects on personnel and the cost of providing a safe environment.

Example 3. The sludge residue from dissolving the base containing diamonds obtained according to the procedures described in example 1, 2, was used as the feed source of the pulsation column. The results of sludge fractionation at various linear upstream velocities are presented in the table. In FIG. 2 is a snapshot of diamonds obtained at a linear upstream velocity of 45 m / h.

Table.

The results of fractionation of sludge residue from dissolution of the base.

No. of experience Linear speed, m / h The presence of inclusions in diamonds,% of the mass. estimated The presence of diamonds in the sludge,% of the mass. estimated 1 thirteen 5 - 2 fifteen 1 1 3 44 - 2 4 51 - 4

Thus, the implementation of the claimed modes in the technical solution: the concentration limits of the sulfuric acid used - provides gentle corrosion conditions for the process, facilitates the selection of structural materials and the disposal of base solutions; the use of an ascending flow with a variable hydrodynamic regime in a pulsation column variant significantly reduces and simplifies the technological scheme and excludes diamond losses in comparison with previously known technical solutions.

Claims (2)

1. The method of extracting diamonds from the diamond matrix of the tool, comprising dissolving the metal binder with the formation of a sludge containing particles of diamonds, separating the electrolyte from the sludge and the selection of diamonds, characterized in that the dissolution of the metal binder is carried out in a solution of sulfuric acid with a concentration of 100-300 g / l with activating additives: nitric acid or ammonium nitrate, and the separation and classification of diamonds is carried out in an upward flow with a variable hydrodynamic regime at a linear speed in the range of 15-45 m / h. 2. The method according to claim 1, characterized in that the concentration of nitric acid or ammonium nitrate varies between 20-50 g / l, and the dissolution process is carried out at a temperature of 60-80 ° C.

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