RU2370764C2 - Nanotechnological method of determining presence and quantitative content of rare and dispersed chemical elements in rocks, ore and products from their processing - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method can be used particularly in searching for mineral deposits and ecological monitoring. From a sample of analysed rocks and/or ore and/or products from their processing and deionised water, taken in ratio of 1:10, a colloidal salt solution is prepared, containing particles of a fraction of the analysed sample with size of 1-1000 nm. The obtained solution is taken of for mass spectrometric analysis with inductively coupled plasma for presence of rare and dispersed elements and simultaneously for determination of their quantitative content. Presence and quantitative content of said elements in analysed rocks and/or ore and/or products from their processing is indicated by reaching corresponding detection limit values.

EFFECT: increased reliability of results with reduction of expenses on analysis.

2 cl

Description

The invention relates to the field of applied geochemistry and can be used in the search for mineral deposits, environmental monitoring and in resolving issues of recycling waste dumps of mining and processing enterprises; in prognostic-geochemical mapping of closed and semi-closed territories, in particular, to detect the presence and quantitative content of rare and scattered chemical elements based on geochemical mapping of the studied territories and their subsequent extraction according to the results of analysis of rock samples, as well as loose deposits of soils and / or parent sediments and / or bottom sediments of modern watercourses and reservoirs.

A known method for the determination of rare metals (1), which relates to the field of hydrometallurgy of gold and silver. However, the known method leaves in the dumps of rocks over 35% of rare metals.

A known method of extracting valuable components from a sulfide concentrate (2), which is based on obtaining a suspension of flotation concentrate with its subsequent leaching. However, the known method involves the use of high pressure technology and aggressive acidic media at elevated temperatures, which leads to significant information loss in the analysis of the concentrate for the presence of valuable chemical elements in it.

A known method for the secondary processing of titanomagnetites (3), which is designed to increase the yield of rare chemical elements in the processing of titanomagnetites while reducing environmental pollution. However, the known method does not have a high yield of rare chemical elements when they are extracted from the concentrate.

Known methods for the search for mineral deposits (4-6), based on the statistical processing of data of elemental analysis of a large array of samples taken over a given network, are widely used to establish the presence, nature and parameters of secondary lithochemical halos and dispersion flows of ore bodies, deposits or specialized geochemicals rocks by the detected change in the contents of the determined elements in the samples. The migration of elements that occurs during the destruction of deposits in the hypergenesis zone can take many forms: the elements can migrate in a solid, liquid, and gaseous state. As a result, scattering halos are formed around the deposits, within which the content of one or another element of interest will, as a rule, be the highest near the deposit and gradually decrease to the side of it.

Known methods for finding mineral deposits (such rare chemical elements as gold, platinum, cassiterite, tungsten, etc.) by the so-called mechanical (lithochemical) halos of dispersion, which are not offset or slightly offset from the root source. These include the widely known clastic-river and boulder-glacier methods. Till lithochemical survey is based on the fact that minerals enclosed among strong debris and boulders can be transported by river waters and glaciers over long distances. However, this search method is not applicable to deep-lying ore bodies, as well as to deposits for which there are no conditions for the mechanical transfer of minerals of the desired elements, or if these elements do not form their own mineral forms at all, i.e. are in a diffuse state (7-8).

A known method for the isolation and extraction of rare chemical elements (9), based on obtaining a raw material suspension from finely ground concentrate to a predetermined size, is the closest among analogues in terms of general characteristics and technical result.

There are also known methods of finding deposits by water halos of dispersion of elements based on the analysis of natural water samples. The chemical composition of the water to a large extent depends on the composition of the rocks and ore masses through which these waters circulate. Theoretically, water halos can have a large extent, however, they can hardly be found at a large distance from the deposits, since when moving through different rocks composing the area, the waters will continuously change their composition (10-12). Elements carried out by aqueous solutions from mineral deposits can be sorbed by highly dispersed mineral and organic products composing the surface of the earth's crust. In this way, sorption halos are formed that occur wherever groundwater comes to the surface and encounters colloidal precipitates capable of sorbing the ions present in the solution.

There is a known geochemical method for searching for mineral deposits (13), which is closest to the proposed invention by technical solution and technical result, based on the analysis of the ultrafine fraction (MASF), adopted as a prototype. The known method includes the separation of soil samples and loose sediments of the ultrafine fraction (5-15 microns), on the particles of which ore and indicator elements in a specific mobile form are secondarily fixed, transferring the sample to a solution and precision analysis of solutions for 22 chemical elements.

The disadvantage of this method is the use, when converting the ultrafine fraction into a solution for further analysis, of strong acids (for example, “aqua regia”), as a result of which not only the sorbed salt forms of the elements pass into the solution, but the “carrier” itself is partially dissolved, moreover, the contribution the latter in the total concentration of the element is predominant. In addition, depending on the natural composition of the sample, the size and distribution of the particles of the finely dispersed fraction can vary significantly, in which case the degree of solubility of the sample, being to some extent a function of particle size, will introduce some uncertainty in the interpretation of the data with respect to “anomalous” values. In addition, far incomplete extraction of nanoparticles of minerals and native metals takes place, because, unlike ions, there is no reliable data that they are sorbed by larger particles (finer than themselves) of a finely dispersed fraction. Thus, in relation to certain rare and scattered chemical elements, geochemical mapping based on the data of the MASF does not allow obtaining clear and objective data on their distribution in the study area of deposits, rocks, parent sediments, dumps, etc. and it does not make it possible to precisely localize the deposit, which requires additional costs for updating the data on the presence of the desired chemical elements in the territory.

The technical result of the claimed invention consists in increasing the reliability, accuracy and reliability of determining the likely presence of rare and dispersed chemical elements in the study area, as well as in significantly expanding the range of defined chemical elements at ultra-low levels of their concentrations in samples of rocks, ores and products of their processing.

The specified technical result is achieved by the fact that in the method for determining the presence and quantitative content of rare and dispersed chemical elements in rocks, ores and products of their processing, soils and loose deposits, based on chemical analysis of ultrafine fraction samples, in accordance with the invention, as samples of ultrafine fraction take a colloidal salt solution prepared from a sample of the studied rock objects and / or ores and / or products of their processing, which is subjected to chemical analysis using mass spectrometry method with inductively coupled plasma for the presence in the colloidal salt solution containing particles of the fraction of the test sample with particle sizes of 1-1000 nm, rare and scattered elements and at the same time to determine their quantitative content, upon reaching which the values of detection limits, equal for each of the totality of rare and scattered chemical elements found in colloidal salt solution in the following values, in μg / L: 0.01 (Au), 0.02 (Pt), 0.03 (Pd), 0.005 (Ag), 0.005 (Rh), 0.02 (Ru), 0.006 (Ir), 0.006 (Re), 0.003 (Tl), 0.03 (Cd), 0.04 ( Hg), 0.1 (Te), 0.01 (Sb), 0.06 (As), 0.03 (Ge), 0.01 (Ga), 0.03 (Mo), 0.03 (W), 0.001 (U), 0.6 (Se), 0.005 ( Bi), 0.01 (In), 0.03 (Sc), by which they are judged on their presence and quantitative content in the studied objects of rocks and / or ores and / or products of their processing.

In addition, the specified technical result is achieved by the fact that the colloidal salt solution is obtained from a sample taken at the test object of rocks and / or ores and / or products of their processing, which is pre-ground to a particle size of 0.074 mm, poured heated to a temperature of 50- 100 ° C with deionized water, taken in the ratio of the sample 10: 1, thoroughly mix the resulting suspension periodically for at least 1 hour, incubated at room temperature for at least 24 hours, after which the suspension is filtered to particle size frac tion no more than 1000 nm.

In accordance with the generally accepted geochemical classification, the group of rare and scattered chemical elements includes elements whose contents in the lithosphere are 1-0.0001 g / t. Some of them are rarely found or do not form their own mineral forms at all, but are in a dispersed state, among which there are chemical elements that are “strategic” for any state — gold, platinoids and uranium.

It is known that a sample of any rock or taken from the dump farms of mining and processing enterprises consists of grains and particles of different dimensions. When fractionating samples, it turns out that the fraction of fractions of different dimensions is not the same for different samples. When fractionating samples using generally accepted scales of dimension. So, for example, the granulometric spectrum of sedimentary rocks is estimated according to the following scale, shown in table 1.

Table 1 Grain size mm The name of the particles of the fraction > 2 mm Coarse 0.05-2 mm Sand 0.005-0.05 mm Siltstone 1 μm - 0.005 mm Clay 1 nm - 1 μm Colloidal and ionic

The clay component of the samples is often enriched with chemical elements, and it is this fraction, as a rule, that is used when carrying out geochemical search methods and in environmental monitoring of bottom sediments and soils. Geochemical halos detected in this way have a significantly higher contrast and, as a consequence, higher information content.

In some cases, it is necessary to divide the clay part of the sample into finer fineness classes. Such separation is carried out, for example, on an Analizetta device in water; The method is based on the Stokes law - separation of particles by size. Fractions from 1 μm (1 × 10 ^-6 m) to 0.005 mm are isolated.

The formation of nanomineralogical research in Russia and abroad dates to the end of the 90s of the last century. The study of nanophases is promoted as an interdisciplinary priority area, and the possibility of such studies is due to the advent of modern devices and methods for direct visual observation of nano-objects, such as high-energy transmission electron microscopy, high-resolution scanning electron microscopy with wave and dispersive-energy spectrometry, tunneling scanning microscopy, atomic force microscopy optical microscopy and others.

Phases with a size of 10 ^-7 -10 ^-9 m are related to nanoindivids. Objects of this order fall on the dimension level of atoms, ions, molecules, complex and colloidal compounds, which differ in physical and chemical properties.

As you know, a significant part of the chemical elements enter the minerals as isomorphic impurities, replacing macrocomponents in the crystal lattice. Some of them accumulate in gas-liquid inclusions, and some are in colloidal-dispersed form in the pore space of the rock. For a number of chemical elements, the scattering state is the main one. It is well known that the lower the average content of a chemical element in the earth's crust, the greater its proportion in dispersed form. In addition, along with electrically neutral particles - atoms and molecules, ions are actively involved in geochemical processes, creating osmotic and electrochemical flows of elements in the aqueous medium of the pore space. Thus, the level of modern analytical equipment allows you to work with particles of nanometer size. The claimed invention provides a method for their isolation from natural objects and subsequent analysis to identify the geochemical information content of this fraction.

Currently, to obtain objective data with the required accuracy and reproducibility, quantitative methods are used to achieve low detection limits, which, first of all, include atomic absorption spectroscopy (AAS), inductively coupled plasma atomic emission spectroscopy (ICP- Nuclear power plants) and inductively coupled plasma mass spectrometry (ICP-MS). However, their distribution in routine exploratory geochemical methods is limited by the high cost of analysis. In addition, the use of various reagents for opening samples and transferring them to the solution often leads to errors associated with the uncontrolled interfering effect of the solution components and solvents, the content of which is many times higher than the concentration of rare and dispersed elements. This effect leads to an increase in the detection limits of the method, so that the content of the desired elements is lower than the attainable limits.

Quite often, various kinds of geochemical and environmental methods are used, as can be seen from the above analogs, leaching for the selective extraction of any elements. So, for samples enriched with organics, leaching with sodium pyrophosphate is used, when using hydroxylamine (hot and cold leaching), most oxides of manganese and iron are dissolved, oxalic acid dissolves all oxide formations and partially weak silicates, a mixture of potassium iodide and ascorbic acid - oxide formations iron, manganese and aluminum. Water extraction (hot and cold) is used either for preliminary washing of the sample, or for determination of water-soluble salts, extraction with hydrochloric acid - acid-soluble components (with a small sample weight, the concentrations of most elements are below the detection limit). In any case, this is a method for the selective extraction of various salts, which does not allow one to obtain an overall picture of the distribution of a wide range of chemical elements within the framework of one type of analysis. When using more aggressive reagents, the selectivity of the extraction of elements decreases, and due to the high background contents of metals in leaching solutions and high detection limits, weak anomalies can be masked. None of this type of leaching is selective with respect to rare and dispersed elements; therefore, it does not increase the sensitivity of analysis and lower the detection limits of chemical elements in rocks, ores, and products of their processing.

The claimed method consists in the analysis of the colloidal salt phase of samples of rocks, ores and products of their processing, which is a part of any sample. Applicants and authors attribute this colloidal-salt part to nanofraction, which is released by water under specially selected conditions. Thus, it can be noted that the claimed method consists in the analysis of nanofraction of soil samples and loose deposits, which are a natural colloidal-salt phase, which is released by water under specially selected conditions. And the analysis of such a colloidal salt solution (nanofraction) allows one to obtain data on the concentrations of 72 chemical elements with detection limits several orders of magnitude lower than in the analysis used in the well-known geochemical search methods.

Analysis of the colloidal salt solution and subsequent recalculation of the contents for the initial sample, taking into account the amount of nanofraction, allows, as shown by numerous laboratory tests at the base of St. Petersburg State University and VSEGEI, to obtain data on the concentrations of rare and dispersed chemical elements with detection limits several orders of magnitude lower, than in the analysis used in known exploratory geochemical methods. The results of the experimental studies conducted (under different basic conditions of the two applicants) showed that the chemical elements present in the samples at ultra-low concentrations, as well as those that do not have their own mineral form, mainly accumulate in the colloidal salt fraction of the samples.

To conduct a comparative analysis, a finely dispersed fraction (TDF) was taken from a sample (300 g) by the dusting method at an installation developed and constructed by VSEGEI. The fraction was taken from a pre-dried sample (without crushing and abrasion). In it, at least 80 wt.% Of the particles had a size of up to 10 μm, and the contribution of larger particles was not more than 20 wt.%. A 100 mg sample of TDF was treated with “aqua regia”, the resulting salts were dissolved in nitric acid (0.1 g sample).

Colloidal systems are extremely sensitive to various external influences - these are unstable, labile systems, and the more complex such a system, the stronger the influence of various factors on its stability. Thus, the processing of the sample by boiling or with chemical reagents, in particular acids or organic reagents, leads, as a rule, to the destruction of the natural equilibrium, the adhesion of colloidal particles to larger aggregates, which can significantly reduce their solubility and, as a result, leads to poor reproducibility and underestimation of the results of the analysis for a certain circle of rare and dispersed chemical elements.

From this point of view, the extraction of the colloidal salt fraction only with water (without the addition of acids) is the most “gentle” with respect to the entire natural system. In addition, water, as a “diluent” of the natural dispersed system, has a peptizing effect on particle aggregates and increases its stability. The extraction efficiency and stability of the resulting solution will depend on the selected conditions (temperature, method of separation of the solution from the solid residue, stabilization time, the introduction of stabilizing additives).

Grinding (abrasion) samples to 74 microns (200 mesh) is a common, well-known practice in the analysis of rocks, since this operation provides the required averaging of the sample and contact of solid particles with chemical reagents (acids and solvents) during decomposition. In the claimed invention, grinding samples to the specified size is necessary for opening pores and rock cracks in order to ensure access of water to salts and colloidal particles adsorbed on a mineral basis. An increase in the degree of abrasion <74 μm leads to a deterioration in the wettability of the powders, which is undesirable to achieve the above technical result. The attainable detection limits for a number of elements are given in table 2. The “gross” value in this application denotes data obtained by ICP-MS, ICP-AES or AAS methods according to standard methods, “gross *" is calculated by the analysis of nanofraction in terms of the original sample.

table 2 Detection limits of rare and scattered elements for gross analysis by the traditional method (gross), as well as in colloidal-salt nanofraction solution (NF solution) and based on the initial sample (gross *) No. p / p Element Detection limit Gross, g / t (standard methods) NF solution, mcg / l Gross *, g / t one Au 0.002 (AAS) 0.01 0.0002 2 Pt 0.04 (AAS) 0.02 0.0004 3 Pd 0.03 (AAS) 0.03 0.0006 four Ag 0.05 (AAS) 0.005 0.0001 5 Rh 0.03 (AAS) 0.005 0.0001 6 Ru 0.1 (AAS) 0.02 0.0004 7 Ir 0.03 (AAS) 0.006 0.0001 8 Re 0.03 (ICP-MS) 0.006 0.0001 9 Tl 0.03 (ICP-MS) 0.003 0.00006 10 Cd 0.1 (ICP-MS) 0.03 0.0006 eleven Hg 0.005 (AAS) 0.04 0.0008 12 Those 1.0 (ICP-MS) 0.1 0.002 13 Sb 0.1 (ICP-MS) 0.01 0.0002 fourteen As 0.6 (ICP-MS) 0.06 0.001 fifteen Ge 0.03 (ICP-MS) 0.03 0.0006 16 Ga 0.05 (ICP-MS) 0.01 0.0002 17 Mo 1.0 (ICP-MS) 0.03 0.0006 19 U 0.01 (ICP-MS) 0.001 0.00002 twenty Se 0.5 (ICP-MS) 0.6 0.01 21 Bi 0.2 (ICP-MS) 0.005 0.0001 22 In 0.01 (ICP-MS) 0.01 0.0002 23 Sc 0.15 (ICP-MS) 0.03 0.0006

Below are examples of the results of experimental studies of samples taken from different territories.

The solutions were analyzed by inductively coupled plasma mass spectrometry on an ELAN-6100 DRC instrument from PERKIN ELMER.

All analyzed elements were divided into five groups in accordance with their prevalence in the earth's crust (table 3).

Table 3 The prevalence of certain chemical elements in the earth's crust Group Degree of distribution Chemical element one Medium Ti, P, Ba, Sr, Zr, Mn 2 Less common Ni, Co, Cr, V, Li, Pb, Cu, Zn, Th, Nb, Y, Ga, Ce, La, Rb, B, Sc 3 Rare Be, Sn, W, Mo, Ta, Hf, Ge, U, As four Very rare Sb, Cd, In, Hg, Se, Ag, Bi 5 Rarest Pd, Au, Pt, Re, Te, Ir, Os, Rh

Example 1

The research results in example 1 demonstrate the effect of the temperature of extraction on the completeness of extraction of the chemical element.

A loose sample of Quaternary deposits of the North-West of Russia (SUZE) was preliminarily dried in air; no further processing was carried out. A colloidal salt fraction (nanofraction) was extracted from a 50 g sample of water. For this, the sample was placed in a glass flask with a volume of 1 dm ³ , filled with 500 ml of hot deionized water (90-100 ° С), thoroughly mixed several times for 4 hours and left to stabilize the colloidal salt solution for 24 hours. If possible, without affecting the sediment, the upper part of the solution was passed through a membrane filter with a pore size

<1 μm. The nanofraction mass was determined by the gravimetric method, for which a 100 ml solution was evaporated to constant weight, and the dry residue was weighed. The solutions were analyzed by inductively coupled plasma mass spectrometry on an ELAN-6100 DRC instrument from PERKIN ELMER.

Element concentrations were calculated in two ways: in nanofraction and in the initial sample from which it was extracted. The results of these experiments are presented in table 4.

The table shows that for different elements the maximum extraction temperature lies in the range of 50-100 ° C and is selected individually depending on the task. If we are talking about a complex of chemical elements, then the optimum temperature can be considered 90 ° C (hot, but not boiling water). As many results of experimental studies show, at a temperature of 30 ° C, the extraction of chemical elements practically does not occur.

Table 4 The content of chemical elements in the colloidal-salt fraction of sandstone extracted from the rock at various temperatures, g / t No. p / p Element Temperature ° C one hundred 90 fifty thirty one Au 0.14 0.59 0.05 0.01 2 Pt 0,03 0,045 0.04 <0.01 3 Pd 0.6 0.5 0.38 <0.01 four Ag 1,1 1.48 0.22 0.01 5 Rh 0,024 0,028 0,033 <0.001 6 Ru 0.006 0,03 0,032 <0.001 7 Ir 0.018 0,023 0,022 <0.001 8 Re 0.005 0.01 0.01 <0.001 9 Tl 0.52 0.38 0.32 0.01 10 Cd 0.27 1.21 0.6 0.5 eleven Hg 0.19 0.33 0.27 0.1 12 Those 0.49 1.79 0.2 0.1 13 Sb 2,31 2,53 2.94 0.1 fourteen As 17.1 26.7 24.2 0.5 fifteen Ge 0.95 0.8 0.67 0.4 16 Ga 22.0 8.85 8.1 1,0 17 Mo 1,5 1.95 2.23 0.5 eighteen W 1.71 1.45 0.75 0.3 19 U 2.18 2,31 1.97 0.5 twenty Se 4.6 9.51 7.08 0.5 21 Bi 0,086 0.47 0.2 0.1 22 In 0.002 0.012 0.015 <0.001

Example 2

The research results in example 2 demonstrate the possibility of reducing the detection limits of noble metals (Au, Pt, Pd) the influence of the temperature of extraction on the completeness of extraction of a chemical element in black shale rock.

As a rule, samples were pre-dried in air; no further processing was carried out. Each sample with a total mass of 350 g was divided into 2 unequal parts. Under a specially selected condition, a colloidal salt fraction (nanofraction), the mass of which was determined by the gravimetric method, was extracted from a sample of a mass of 50 g (first part) under specially selected conditions. To isolate nanofractions, a membrane filter with a pore size <1 μm was used. The nanofraction mass was determined by the gravimetric method, for which a 100 ml solution was evaporated to constant weight, and the dry residue was weighed. Subsequently, the concentrations of chemical elements were determined based on the mass of nanofraction.

Thus, a series of 10 samples of black shale rock was dried, crushed, and abraded to an average particle size of less than 0.07 mm. Further, the extraction and analysis of nanofraction was carried out similarly to that described in example 1. The extraction temperature was 90 ° C. The analysis data are presented in table 5.

Table 5 The content of noble metals in black shale rocks: gross - "complete acid decomposition - AAS, in nanofraction - ISP-MS No. p / p Au ppm Pt ppm Pd ppm gross in nf gross * gross in nf gross * gross vnf gross * one 0.0036 1.22 0.0035 <0.04 1.51 0.004 <0.03 2.8 0.008 2 <0.002 0.35 0.003 <0.04 4.39 0.04 <0.03 9 0.086 3 <0.002 0.13 0.0007 <0.04 1.31 0.007 <0.03 5.62 0.03 four <0.002 0.04 <0.0002 <0.04 1.36 0.003 <0.03 11.2 0.026 5 <0.002 0.17 0.0006 <0.04 3.53 0.013 <0.03 18.1 0.07 6 <0.002 0.37 0.0036 <0.04 5.24 0.05 <0.03 7.98 0.08 7 <0.002 0.15 0.0003 <0.04 1.46 0.003 <0.03 14.6 0.028 8 <0.002 <0.001 <0.0002 <0.04 3.42 0.021 <0.03 9.19 0.06 9 <0.002 0.001 <0.0002 <0.04 3.01 0.014 <0.03 47.7 0.23 10 0.0046 0.063 0.0005 <0.04 0.079 0.0006 <0.03 <0.1 <0.0006

Example 3

The research results in example 3 demonstrate the choice of stabilization time of the colloidal saline solution.

The gabbrodiorite sample was dried, crushed, and abraded to an average particle size of less than 0.07 mm. Next, the extraction of nanofraction was carried out similarly to that described in example 1 with the difference that the sample was 100 g. The extraction temperature was 90 ° C. The amount of nanofraction in 100 ml of the solution was determined after aging for 6, 12, 18, 24 and 30 hours. It turned out that in the process of aging, there is first a slight increase in the recovered fraction, then a decrease due to spontaneous coagulation, and after 24 hours, stabilization of the colloidal salt solution is observed. The analysis data are presented in table 6.

Table 6 The choice of time for stabilization of colloidal saline No. p / p The exposure time, hour. The amount of nanofraction in 100 ml of solution, mg one 6 52.1 2 12 88.3 3 eighteen 75.5 four 24 63.2 5 thirty 63.5

Example 4

The research results in example 4 demonstrate the choice of the ratio of the sample / extractant.

When choosing the relative volume of extractant, we were guided by the fact that its minimum amount should be sufficient not only to wet the sample, but also to mix the suspension. For a 25 g sample, this volume is at least 125 ml.

To the weighed portions of the gabbrodiorite sample in an amount of 25 g, various amounts of deionized water heated to 90 ° С were added. After stirring, settling and filtering, the amount of nanofraction in 100 ml of colloidal salt solution was determined. With a sample: extractant ratio of 1: 5, the amount of nanofraction was 0.92%, with a ratio of 1:10 - 1.8%, with a ratio of 1:20 - 1.8%. This dependence can be explained by the fact that with an insufficient amount of reagent, partial destruction of the colloidal-salt system occurs: larger particles stick together and precipitate. When diluting the solution, the amount of nanofraction does not change, but excessive dilution of the solution leads to the fact that the concentrations of some elements are below the limits of their detection. Therefore, a ratio of 1:10 should be considered optimal.

Example 5

The research results in example 5 demonstrate the rationale for the use of deionized water.

To select the degree of purification of the extractant in the experiments, tap, distilled, bidistilled, and deionized water was used. Table 7 shows the results of an experiment on the analysis of a colloidal salt solution of granodiorite, from which it follows that deionized water has the best extruding properties for rare and dispersed elements. Apparently, this is due to its high degree of purification not only from pollutants, but also from soluble salts of sodium, potassium, calcium, magnesium, etc.

Table 7 The choice of the degree of purification of the extractant of rare and trace elements No. p / p Water quality The content of the element in colloidal saline, μg / l Au Sb Tl one Tap 0.42 3.12 0.12 2 Distilled 0.65 7.83 0.31 3 Bidistilled 0.70 8.0 0.40 four Deionized 1.84 15.4 0.65

Based on the results of experimental studies of nanofractions based on numerous samples from different territories and regions and carried out in different laboratory conditions by applicants (St. Petersburg State University and VSEGEI) using modern equipment (based on nanotechnology), it is thus shown that the assessment of the contents of rare and scattered elements in samples of rocks, ores and products of their processing through the analysis of the colloidal salt fraction (nanofractions) has a number of advantages compared to known methods:

a) a higher degree of differentiation in the content of elements in various samples;

b) due to the "concentration" of rare and scattered elements in the nanofraction, their content is several orders of magnitude higher than in the initial sample, i.e. in samples in which the content of an individual element is below the detection limit, in nanofraction is determined as a real value; the result of work in the field of real concentrations, and not near the detection limits, is a good reproducibility of the analysis and a decrease in the determination error;

c) there is no ambiguity factor for the determination of some elements arising from uncontrolled isobaric overlays in the presence of chloride ion for samples with different matrix compositions;

d) it is possible to simultaneously determine in samples a wide range of rare and dispersed chemical elements without additional decomposition and analysis procedures;

e) the claimed method, containing the separation of the colloidal salt fraction (nanofraction) from soil samples and loose deposits by extraction with water under special conditions, ensures that its native (natural) form is preserved in the absence of “carrier” particles, freeing a useful signal from masking it the main components of the overlapping strata.

The claimed method for determining the presence of rare and scattered chemical elements in nanofractions, in addition to increasing the reliability and reliability of their search, can significantly expand the range of elements being determined and obtain reliable information at ultra-low concentration levels, which generally leads to a significant increase in the likelihood of identifying and reliability of the assessment of anomalous geochemical systems while reducing the cost of analytical work.

The use of the invention in environmental studies will also allow the identification of mobile (migratory) forms of chemical elements, which, due to their active participation in biological cycles, are the most environmentally hazardous.

Separation of nanofraction from off-balance ores and products of mining and processing plants will allow to extract rare and dispersed chemical elements from them in a low-cost way.

List of used literature.

1. RF patent No. 2224806.

2. RF patent 2221881.

3. RF patent 1524515.

4. Antropov V.M. Forms of finding elements in dispersion halos of ore deposits. L., 1975;

5. Barsukov V.L., Grigoryan S.V., Ovchinnikov L.N. Geochemical methods of prospecting ore deposits. M., 1983.

6. Alekseenko V.A. Geochemical methods of prospecting for mineral deposits. M., 2002.

7. Safronov P.I. Fundamentals of geochemical methods of prospecting ore deposits. L., 1971.

8. Solovov A.P. et al. Handbook of geochemical prospecting for minerals. M., 1990.

9. WO 02/24966, publication date 03/28/2002.

10. Udodov P. A., Shvartsev S. L., Stories N. M. Methodological guide to hydrogeochemical prospecting for ore deposits. M., 1973.

11. Goleva G.A. Hydrogeochemistry of ore elements. M., 1977.

12. Krainev S.R. Fundamentals of Hydrogeochemical methods of searching for ore deposits. M., 1983.

13. Sokolov S.V. and others. Temporary guidelines for conducting geochemical searches in closed and semi-closed territories. SPb., 2005 (prototype).

Claims (2)

1. Nanotechnological method for determining the presence and quantitative content of rare and dispersed chemical elements in rocks, ores and products of their processing, based on the chemical analysis of the sample, characterized in that the chemical analysis is subjected to a colloidal salt solution prepared from a sample of the studied rock objects, and / or ores and / or products of their processing and deionized water taken in a ratio of 1:10, which is carried out by mass spectrometry with inductively coupled plasma for the presence of colloid -salt solution containing particles of the fraction of the test sample with particle sizes of 1-1000 nm, rare and scattered elements and at the same time to determine their quantitative content, upon reaching which the values of the detection limits are equal for each of the entire set of rare and colloidal salt solution scattered chemical elements of the following values, μg / L: 0.01 (Au), 0.02 (Pt), 0.03 (Pd), 0.005 (Ag), 0.005 (Rh), 0.02 (Ru), 0.006 (Ir), 0.006 (Re), 0.003 (Tl), 0.03 (Cd), 0.04 (Hg), 0.1 (Te), 0.01 (Sb), 0.06 (As), 0.03 (Ge), 0.01 (Ga), 0.03 (Mo), 0.03 (W), 0.001 (U), 0.6 (Se), 0.005 (Bi), 0.01 (In), 0.03 (Sc), they are judged on Ichii and quantitative content in the investigated objects of rock and / or ore, and / or their products. 2. The method according to claim 1, characterized in that the colloidal salt solution is obtained from a sample taken at the test object of rocks, and / or ores, and / or products of their processing, which is pre-ground to a particle size of 0.074 mm, poured heated to a temperature of 50-100 ° C with deionized water, thoroughly mix the resulting suspension periodically for at least 1 hour, incubate at room temperature for at least 24 hours, after which the suspension is filtered to a particle size fraction of not more than 1000 nm.