RU2700816C1 - Method for x-ray radiometric separation of gold-containing ores - Google Patents

Abstract

FIELD: mining.SUBSTANCE: invention relates to radiometric methods for dressing of ores and other minerals, particularly, to X-ray radiometric separation, and, in particular, is intended for sorting of gold-containing ores. Method of X-ray-radiometric separation of gold-containing ores consists in sorting ores by X-ray fluorescence method with registration of iron RIS and strontium RIS and using additional iron and strontium enrichment criteria together with enrichment criterion by accompanying element. Subsequently, all three enrichment criteria are compared with the corresponding pre-set threshold values by the "OR" logic. Depending on absence of quartz or elements accompanying gold in gold-bearing ores, sorting may be carried out according to one or several proposed enrichment criteria.EFFECT: higher efficiency of method for sorting of gold-containing ores at X-ray radiometric separation.4 cl, 8 dwg

Description

The invention relates to radiometric methods for beneficiation of ores and other minerals, and more particularly to x-ray radiometric separation, and in particular, is intended for sorting gold-bearing ores.

A known method of photometric sorting (FMS) of gold-bearing ores, which consists in irradiating gold-quartz ores with X-ray and optical radiation. In the process of moving the material under the irradiators, the parameters of the X-ray fluorescence spectrum and reflected optical radiation characterizing the color characteristics are recorded. As a separation criterion, a combination of the measured characteristics and radiation parameters is used, the spatial heterogeneity indices due to the content of quartz grains, veins, veins, massive quartz in gold-containing ores (RF Patent No. 2215585, class B03B 13/06, op. 10.11.2003) .

The disadvantages of this method include the possibility of its use only for gold-bearing quartz ores, where quartz is the host medium for gold, although contrasting optical properties of gold-containing quartz ores are not characteristic of all deposits.

Moreover, according to the experience of using FMS for sorting gold-containing ores of quartz type, the ore must be pre-washed from sludge, contaminants and greases, which significantly complicates the whole technology and worsens the environment.

In addition, this method is technically difficult to implement due to the need for the simultaneous use of two fairly complex methods and equipment.

The closest analogue of the proposed method is a method of x-ray concentration of ores of gold-quartz-sulfide type or sulfide type, where gold is associated with sulfide elements Fe (pyrite), Cu (chalcopyrite), Zn (sphalerite), As (arsenopyrite), Pb (galenite), Bi (bismuthine), Sb (antimonite) (Author's certificate No. 952384, B07C 5/34, op. 23.08.1982).

This known method consists in sequentially passing pieces to a source of primary x-ray radiation, exciting secondary x-ray radiation in a piece, registering secondary x-ray radiation from each piece, and dividing the pieces relative to a predetermined threshold value of the enrichment criterion, while measuring the characteristic fluorescence x-ray (XRI) and scattered from a piece of x-ray radiation by an x-ray detector. As an enrichment criterion for gold-bearing ores, the ratio of the HRI intensity of K- or L-series of elements accompanying gold to the intensity of the primary radiation source scattered by a piece of x-ray radiation is used. In this case, the intensity of the scattered radiation is recorded in the energy region of the photopeak of this radiation.

The known method has the following disadvantages. Firstly, it can only be used for gold-bearing sulfide ores, where there is a high correlation (or close relationship) of gold with the accompanying sulfide elements. Most often, even such a high correlation, and even more so a weak correlation, does not allow for some ores to achieve the required sorting efficiency.

Secondly, the application of the known method for gold-bearing ores of the quartz-sulfide type is possible only in those cases where the quartz pieces are actually represented by pure bulk quartz. If quartz is represented by small impregnation, thin veins, veins, grains, has a layered structure, manifests itself in intergrowths, then this method does not detect it.

Both disadvantages significantly reduce the efficiency of sorting gold-bearing ores and often do not allow to obtain the required technological parameters of pre-concentration. These indicators primarily include:

- Au content in sorting tails;

- the relative output of the tails;

- Loss of gold in the tails of the sort.

These indicators are interconnected and limit each other. Pre-enrichment, as a technology, is considered effective if the gold content in the sorting tailings corresponds to the dump (for example, less than 0.3-0.4 g / t), and the maximum yield of this product (breed) and the minimum loss of gold in it are achieved.

The optimal (best) ratio between these indicators is possible only with the high efficiency of the method for sorting gold-bearing ores, therefore, the object of the invention is to increase the efficiency of the method of sorting gold-containing ores during x-ray radiometric separation. The specified problem is solved as follows.

Studies have found that most gold-bearing ores can be effectively sorted according to three criteria:

1. According to Fe, the minimum content of which corresponds to quartz pieces, which for the most part are a gold-containing host medium. The rock contains much more Fe, and quartz can be separated from the rock relative to a given value of the enrichment criterion — the ratio of the CXI of Fe to scattered radiation.

2. In the case of quartz being in the oxidized form (increased Fe content, equivalent and even larger than the rock), the ratio of the CRI intensity of the rock element Sr to the scattered radiation intensity is used as an enrichment criterion for the separation of quartz. In the quartz material of ores, Sr is also contained in minimal amounts compared to rock.

In the absence of obvious pieces of quartz material in ore, gold is concentrated in pieces with the presence of silicification (fine impregnation, grains, veins, veins, interlayers), often invisible with other methods of sorting gold-bearing ores. The presence of silicification in pieces is also detected through Sr - it is much more in the rock. In both cases, the same Sr enrichment criterion is used.

3. Gold-bearing ores with any presence of genetic satellites in the ore (sulfide elements) according to the known method are sorted according to the well-known concentration criterion — the ratio of CRI (K - or L-series) of the accompanying element (Ce) to the scattered radiation.

Thus, in order to increase the efficiency of sorting gold-bearing ores during X-ray radiometric separation, it is necessary to sort them using immediately 3 or 2 concentration criteria, depending on the type, geological and mineralogical properties and material composition of these gold-containing ores.

Option 1 - the use of three enrichment criteria, if research has established a higher efficiency of the simultaneous application of three criteria according to the following logic:

triple logic (OR):

OR

OR

where: K ₁ (Ce), K ₂ (Fe), K ₃ (Sr) are the enrichment criteria for the associated element, iron and strontium, respectively;

NСе, N _Fe , N _Sr - HRI intensity of the accompanying element, iron and strontium, respectively;

N _S is the intensity of the scattered x-ray radiation;

P ₁ (Ce), P ₂ (Fe), P ₃ (Sr) - the threshold value of the enrichment criterion (sorting thresholds), respectively.

Logic (“OR”) for each enrichment criterion denotes the condition for choosing a piece rich in gold (concentrate):

"OR" greater than P ₁ (contains sulfides)

"OR" less than P ₂ (quartz piece)

"OR" less than P ₃ (the presence of silicification in a piece).

All other pieces, the numerical values of the enrichment criterion of which do not correspond to the implementation of this logic, belong to the breed.

The triple OR logic is universal for most gold-bearing ores, but a simplified logic can be used depending on the particular ore:

a) Double (if two enrichment criteria are sufficient for effective sorting)

b) Single (if one enrichment criterion is sufficient for effective sorting)

The proposed method can be implemented in SRF separators designed for sorting ores by the X-ray fluorescence method and known as effective equipment for the separation of a wide variety of ores.

The general view and composition of the SRF separator is shown in figure 1, where 1 is an adapter, 2 is a shutter, 3 is a vibratory feeder, 4 is a distributor, 5 is a universal x-ray unit (BUR), 6 are actuators, 7 are estrus tails, 8 are estrus product, 9 - estrus spill, 10 - casing for the video system, 11 - power cabinet, 12 - protective casing. The figure 2 explains the principle of operation of the separator, as well as the geometry of the measurement and selection of pieces of ore in the separators SRF.

Technologically and technically, X-ray radiometric separation (RRS) in SRF separators is carried out as follows. The machine (sortable) class to be enriched is fed to the SRF separator sorting machine in the receiving hopper (adapter). The feed vibrating feeder of the sorting machine provides a dosed continuous unloading of ore from the receiving hopper and feeding it to the pickup (13). The spreader has a tray structure and forms an ore flow (14) with a piecewise feed into the measurement and selection zone in the free fall mode. Each piece is subjected to scanning x-ray irradiation (15) (primary radiation) due to the natural movement of the piece in the narrow gap radiation band.

The spectrum of secondary (reflected) radiation (16) from each piece is recorded by the detection unit (17), which is part of the X-ray unit (18), and is subjected to automatic computer processing, determination of the analytical parameter of the separation characteristic and comparison of the obtained value with a given threshold value (sorting threshold )

The measuring and controlling system of the separator (based on industrial computers) generates a control signal to actuate the actuator (19) per piece with an increased or decreased content of valuable components or impurity elements. The actuator is triggered by changing the trajectory of the fall of the piece, which is sent to the heat of the selected product (20). The remaining pieces fall without deviating the trajectory into another estrus (21), usually pieces of that product (concentrate or tails) that are smaller are beaten off. Moreover, the impact force of the piece by the actuator is dosed in proportion to the size (weight) of the piece.

The proposed new method for increasing the efficiency of sorting gold-bearing ores during X-ray radiometric separation can be implemented on various models of SRF separators in laboratory and industrial conditions.

The tables show comparative technological indicators of sorting obtained during the separation of gold-bearing ores of various deposits according to the known method and using the new method for all three proposed options (with a different number of beneficiation criteria).

All the above examples confirm the effectiveness of the proposed method of x-ray radiometric beneficiation of gold-bearing ores for each of the possible options.

The choice of the optimal application of the proposed method for gold-bearing ores of each particular deposit is based on the study and analysis of spectral information obtained on SRF separators when detecting secondary (characteristic) x-ray radiation from ore samples and rocks of this deposit.

Typical secondary radiation spectra of ore and rock samples from one of the typical quartz-sulfide gold-bearing deposits are shown in figures 3-7.

The figure 3 presents the spectrum of the ore sample, the presence of quartz in which is confirmed by a small photopic peak Fe. Sr is observed in small quantities, also confirming silicification. Both signs reinforce each other.

Figure 4 shows the spectrum of an ore sample, the strong silicification of which emphasizes the absence of Sr. In this example, Fe cannot be used as a separation feature because of its large amount.

In figure 5, the spectrum of the rock sample of the deposit, which is characterized by all three separation signs confirming the absence of gold: a high content of Fe (no quartz), a high content of Sr (no silicification) and all elements accompanying gold (As, Cu, Zn) are completely absent.

In figure 6, the spectrum of the ore sample of the deposit, which is separated into the concentrate according to the usual separation feature - a related element, in this case, Cu and Zn, As is absent. If Fe and Sr were used in this example, this sample would be taken to separation tails.

In figure 7, the spectrum of the ore sample, which is separated into the concentrate by the usual separation feature - a concomitant element As, in this case Cu and Zn are of secondary importance. Also, as in the previous example, if Fe and Sr were used in this example, this sample would be taken to separation tails.

The spectra presented in the figures clearly show the work of each dividing characteristic separately and in total, which confirms the difference of the new method according to the claims for it.

Similar x-ray spectra from ore and rock samples are characteristic of many gold-bearing deposits of the quartz-sulfide type (formation).

The validity of the proposed method

X-ray radiometric concentration is confirmed by the results of a study of the dependence of the gold content in ore on the content of iron and strontium. The graphs presented in figure 8, constructed according to the results of analytical tests of pieces of ore with a grain size of -80 + 20 mm (in the amount of 332 pieces), confirm the inverse dependence of the Au content on the content of Fe and Sr.

Claims (4)

1. The method of x-ray radiometric enrichment of gold-bearing ores, which consists in sequentially passing the pieces in front of the sensor, irradiating the pieces with primary x-ray radiation, excitation in the pieces of a secondary x-ray measurement from each piece, while measuring the characteristic fluorescence x-ray radiation (CXI) of the gold-related element and the scattered piece of x-ray detectors using the HRI intensity ratio of concomitant gold e the element to the intensity of the x-ray scattered by the piece as an enrichment criterion, separation of the pieces relative to a given threshold value of the enrichment criterion, characterized in that additionally the CRI of iron and CRI of strontium are additionally used, additional enrichment criteria for iron and strontium are used together with the enrichment criterion for the associated element and compare all three enrichment criteria with corresponding given threshold values according to the logic "OR". 2. The method according to p. 1, characterized in that when sorting gold-bearing ores in which quartz is absent or is present only in oxidized form, only enrichment criteria for the gold-related element and strontium are used, which are compared with the corresponding threshold values by the logic "OR" . 3. The method according to p. 1, characterized in that when sorting gold-bearing ores in which there are no elements accompanying gold, sorting is carried out according to the criteria for the enrichment of iron and strontium, comparing them with the corresponding threshold values according to the logic "OR". 4. The method according to p. 1, characterized in that in the absence of a gold-containing element and quartz in the gold ore, the sorting is carried out according to one criterion for strontium enrichment.

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