SU1608515A1 - Method of preparing samples of platinum-containing materials for atomic spectral analysis - Google Patents

Abstract

The invention relates to analytical chemistry, namely, to chemical-atomic emission methods for analyzing products containing precious metals, and can be used in non-ferrous metallurgy in analyzing concentrates of platinum metals KP-1 - KP-6, copper-nickel sludges, ores, tailings . The method allows to reduce the duration of the analysis of platinum metal concentrates, to improve the working conditions, as well as the metrological characteristics of the analysis. It involves dissolving the sample in a closed volume in hydrochloric acid in the presence of an oxidizing agent at 160–180 ° C and analyzing the resulting solution by an atomic emission method with inductively coupled plasma, the sample being dissolved in a mixture of hydrochloric acid, manganese dioxide and hydrogen peroxide. Mixing the solution with manganese dioxide powder is carried out after sealing the volume and setting the desired temperature mode by rotating the reaction vessel. 1 hp ff, 5 tab.

Description

i-the invention relates to analytical chemistry, namely to chemical emission methods for the analysis of products containing noble metals (platinum metals, gold and silver), and can be used in color metaplurgy in the analysis of commercial products - concentrates of platinum methanol KP-1 - KP-6, and industrial products - copper-nickel sludge, ores, tailings.

The purpose of the invention is to reduce the duration of the analysis by reducing the time for complete dissolution of the sample, increasing the accuracy and reproducibility of the analysis results, reducing the detection limits, improving the level of labor and the metrological characteristics of the analysis.

Tables 1 and 2 show the results illustrating the effect of the ratio of the components of the reaction mixture and the temperature on the completeness and duration of the opening of the platinum metal concentrates at 180 ° C (Table 2 shows the KP-2 concentrate).

The interaction in the system is as follows: manganese dioxide oxidizes hydrochloric acid, the resulting chlorine oxidizes silver, platinum and gold, which otherwise, being in the form of metals, catalyzes the process of decomposition of the peroxide. The chlorine produced also catalyzes the decomposition of peroxide, but to a lesser extent than metallic silver, platinum and gold. Thus, the oxidation of these metals with chlorine contributes to the elimination of powerful catalysts from the process. The decomposition of peroxide is slower. Further, at elevated temperatures, the following reactions occur in the system:

H 2C1 2H, C1 g + 2II20 (O Cl, + 2H. 0 (2) The intermediate product of reactions (1) and (2) is atomic chlorine; which is more reactive than molecular.

The combined action of two oxidizers leads to the existence in the system of a constant low concentration of atomic chlorine and neutralizes the catalyzing effect on the hydrogen peroxide of metals present in the samples, which ensures the achievement of a positive effect.

When the closed vessel rotates at the moments of its rotation, the sample particles stick to the bottom of the quartz tube due to the wetting effect of water and remain in the gas phase. Thus, it is not just the mixing of the components of the mixture and the sample, but the situation is realized in which the sample during the rotation of the ampoule is either in solution or in the gas phase saturated with chlorine. The optimal rotation speed of the autoclave is equal to rpm. Table 3 shows the effect of the rotation speed of the closed vessel on the duration of the opening of the KP-3 concentrate at a temperature of 180 ° C; the ratio of the components of the reaction mixture and the sample is as follows: 0.1 g KP-3 +

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0

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+ 0.2 MP02. + 17.7 g HC1 (, 18 g / cm) + 5.55 g H.202. (d 1.11 g / cm3).

Example K Determination of the content of noble metals in concentrate KP-1, containing, Mac.%: Ag 13.- .. 14; Au 2-4; 1 g 0.05-0.09; Pd 45-49; PC 12-13; Rh 0.2-0.5; Ru 0.05-0.15,

A quartz tube is placed in: a weighing concentrate weighing 0.1 g, 17.7 g of hydrochloric acid (density 1), and 5.55 tons of hydrogen peroxide solution (density 1.11 g / cm) are introduced. 0.2 g of manganese dioxide is poured into a Teflon cup attached to a Teflon-coated autoclave. The tube is capped and placed in a metal holder with a Teflon gasket and fixed with a nut to ensure tightness. An autoclave assembled in this way is placed in a thermostatic chamber heated to 160–180 ° C, the autoclave is fixed to the shaft and an electric motor is turned on that rotates the autoclave in a vertical plane, perpendicular to its axis of attachment at a speed of 10 rpm. The temperature in the chamber is set by a contact thermometer. After 40 min, the thermostatting is stopped, the autoclave is taken out of the chamber, cooled with water and opened in a hood. The solution from the tube was quantitatively transferred into a 100 cm volumetric flask, 15 cm of a 37% hydrochloric acid solution was added. The volume of the solution is made up to the mark with water and a solution is obtained by opening P1, which is then analyzed for the content of Ag, Au, Pd, Pt, Rh, Ru. To determine Ir, 5 cm of the PI solution is shaken for 1 min with 5 cm of a 0.05 M solution of di-2-ethylhexyldithiophosphoric acid (D2 EHDTPA) in chloroform to remove copper. Analyze the upper aqueous solution of P2.

Prepare comparison solutions: Solution A containing 400 mg / dM Mp; Solution B, containing 250 mg / cm Ag and 400 mg / dM Mp; solution B, containing 500 mg / dm Pd and 400 mg / dm Mp; solution G, containing 50 mg / dm Ag, 50 mg / dm Au, 1 mg / dm Ir, 120 mg / dm PC, 25 mg / dm Rh, 10 mg / dm Ru, 400 mg / dm Mn; solution D containing 10 mg / dm Au, 0.2 mg / dm Ir, 40 mg / dm PC, 5 mg / dm Rh, 2 mg / dm Zi, 400 mg / dm Mp.

516085

Solutions PI and P2 and solutions of Comparison A, B, C, D, D are analyzed on an emission spectrometer with an inductively coupled plasma. Analysis conditions: Moif HocTb ,. supplied to a plasma of 1.2 kW;

flows, l / min: external 14.5; auxiliary 0.2; the transport height of the observation zone is 15 mm. wavelengths, nm: Ag, 06; Au 242.79; 1g 224.26; Pd, 45; PC 214.42; Rh 343.48; Ru, 27; Mh 257.61. The graphs are plotted in the coordinates: the ratio of the line intensity of the determined e-element / the intensity of the ganza line (rel. Units) is the concentration of the element determined (mg / dm). According to the calibration schedules are

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autoclave the sample (Cp, mg / dm). The content of the element to be determined in the concentrate, C%, is found by the formula Cpx m%, m is the sample weight, mg. S sample KP-1 found,%: Ag 13,26; 3.11; Ir 0.068; Pd 48.14; PC 12.26; ), 284; Ru 0.11. The total analysis time is: 3 hours left. To carry out the anapo technique, taken from the prototype, 5 hours. Reducing the time of shalis is achieved due to more grinding of the starting material, more than a simple processing of the resulting solution.

Dimension 2. Determination of the content of noble metals in the concentration of KP-2, containing,%: Ag 40-50; 1.2-0.8; Ir 0.005-0.015; Pd 5-20; -five; Ru 0.2-1; Rh 1-5.

a quartz tube is placed on the KP-2 concentrate concentrate weighing 0.1 g; 17.7 g of hydrochloric acid solution (, 18 g / cm), 5.55 g. Of hydrogen peroxide (d 11 g / cm) and 0.2 g of Mar dioxide, are then carried out in the same manner as in Example 1 , before operations with a mercury flask with a capacity of 100 cm,

25 cm of hydrochloric acid was injected and then again in accordance with Example 1. In the KP-2 test, gno,%: Ag 48.32; Au 0.65; Ir

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01) the analysis time was 3 hours. The method described in the prototype is possible due to incomplete opening.

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Froze Determination of the content of noble metals in the sludge of electrolytic copper production, containing,%: Ag 6-7; Au 0.2-0.4: Pd 2-3; PC 0.4-0.7; C 36; Ni 20; Se 8. Analyze the same way. in example 1. In the sludge electrolytic copper production found,%: Ag 6.63; Au 0.30; Pd 2.53; Ps 0.58%. The total analysis time is 3 hours.

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Example 4: Determination of the content of noble metals in a slurry of an electrolytic production of nickel containing,%: Ag 0.1-0.5; Au 0.04-0.08; Pd 1.4-1.6; Рс 0,2-0,4; Rh 0.02-0.07; C 36; Ni 14; Fe 8. The analysis is carried out in the same manner as in Example 1. In the sludge of electrolytic nickel production,% Ag 0.17 was found, - Au 0.051; Pd 1.54; RS 0.39; Rh 0.054. Total analysis time 3 h.

Examples 3 and 4 show that the proposed method of analysis can be used to quickly determine small amounts of platinum metals, gold and silver in products containing large amounts of non-precious metals.

Table 4 shows the results of the analysis of state standard samples of platinum concentrates KP-1 and KP-2, performed by the proposed method (C +),%.

From the data given in Table 4, it follows that the analysis of platinum concentrates by the proposed method does not give significant systematic errors; random errors at the same time allow to obtain smaller values of confidence intervals, i.e. improved analysis accuracy is achieved. The total duration of the complete analysis of four samples of the concentrates by the proposed method averages 3 hours.

Table 5 shows some data characterizing the analysis of platinum-containing materials by the proposed method, as well as by known methods and according to the current industry standards.

Comparing the methods of platinum metal concentrates shows that the proposed method significantly, by 50-100 times, reduces the duration of the analysis, improves the conditions of the VIE work of the staff.

the mass of the sample taken for analysis is reduced.

The advantages of the method in comparison with the known method are the reduction of the analysis time (when the solution is cooled, potassium salts do not precipitate and no additional time is required to dissolve them), improved working conditions due to the fact that there is no release of reagents, such as chlorine, into the atmosphere, as well as obtaining stable solutions of dissection, reduction of the total salt background in these solutions, the use of an internal standard for instrumental analysis, which allows to improve the metrological akteristiki analysis;

Claims (1)

1. The method of preparing samples of platidoderzhaschim materials for atomic spectral analysis, including the dissolution of the sample in a closed volume in a solution of hydrochloric acid in the presence of an oxidant at 160-180 0 five 0 five so that, in order to reduce the duration of the analysis by reducing the time for complete dissolution of the sample, improve the accuracy and reproducibility of the results, reduce the limits of detection of the elements being eaten, the dissolution of the sample is carried out in a mixture of concentrated hydrochloric acid 1.18 g / cm ; manganese dioxide and hydrogen peroxide solution 1.11 g / cm with a mass ratio of the corresponding components of the reaction mixture and sample (180-470):: (2-4): (55-110): V.V 2, Method 1, characterized in that, for the purpose of improvement; working conditions, mixing the hydrochloric acid solution containing hydrogen peroxide with manganese dioxide powder is carried out in an autoclave after its 1 sealing and setting the temperature mode by mixing the contents of the autoclave by rotating it in a plane perpendicular to the axis of attachment at a speed of 15 t 5 rpm. 0.2 0.3 0.2 0,2, 0.2 0.2 0.44 0.66 0.3 0.3 0.3 0.3 0.5 0.3 0.2 0.2 0.1 Concentrate KP-1 5.55 5.55 5.55 5.55 Concentrate KP-2 5.55 5.55 5.55 5.55 5.55 5.55 Concentrate KII-5 5.55 5.55 5.55 5.55 Table 1 14 (sediment) 12 (sediment) 0.7 0.7 1.5 one one one one 0.7 0.7 1.5 (precipitate) (sediment) (sediment) (precipitate) 1 (sediment) 1 (sediment) 1.5 0.7 1.5 (sediment) Ponenta reaction mixture and samples: O. Obg KP-2 + + 23.6 g HGl, (d-l, 18l / cm) - + 5.55 g 1.11 g / cm) + + 0.3 g toOj. Note. (Clj) „- certified value of the contents of elements in the GSO. T a 6 faces Rotation speed, rpm Time to open, h Note, x- rotation of the vessel at a speed of 10 rpm for 5 min, then the rotation is stopped. and 1608515 Note. - analysis is impossible due to incomplete opening of the sample. 12 Table 5