TECHNOLOGY OF SEGREGATION-DIFFUSION CONCENTRATION AS A METHOD FOR THE EXTRACTION OF FINE AND THIN GOLD FROM WASTE PRODUCTS

ТЕХНОЛОГИЯ СЕГРЕГАЦИОННО-ДИФФУЗИОННОЙ КОНЦЕНТРАЦИИ КАК МЕТОД ИЗВЛЕЧЕНИЯ МЕЛКОГО И ТОНКОГО ЗОЛОТА ИЗ ОТВАЛЬНЫХ ПРОДУКТОВ

Научная статья

Истомина Е.Е.¹, ^*, Куранов М.Н.²                 

¹ ORCID: 0000-0002-1243-4434;

² ORCID: 0000-0003-4910-6239;

¹ Иркутский государственный университет, Иркутск, Россия;

² ООО «Монолит», Иркутск, Россия

* Корреспондирующий автор (gamlet421[at]yandex.ru)

Аннотация

В статье рассматриваются обоснование и ключевые причины в золотодобыче в отвалах и хвостах. В России необходимо увеличение добычи золота на разработанных месторождениях, путем использования отвалов и хвостов, для добычи золота без вовлечения в разработку новых месторождений. Ресурсы отвалов содержат золото и могут быть применены как новый вид сырья. Выделены основные этапы использования технологии извлечения мелкого и тонкого золота из отвальных продуктов месторождения. Авторами исследовано практическое применение технологии извлечения мелкого и тонкого золота из отвальных продуктов на основе сегрегационно-диффузионной концентрации в золотоизвлектательной фабрике на месторождении «Высочайший».

Ключевые слова: мелкое и тонкое золото, концентрат, золотосодержащая руда, отвальные породы, сегрегационнодиффузионная концентрация.

TECHNOLOGY OF SEGREGATION-DIFFUSION CONCENTRATION AS A METHOD FOR THE EXTRACTION OF FINE AND THIN GOLD FROM WASTE PRODUCTS

Research article

Istomina Е.Е.¹, ^*, Kuranov M.N.²

¹ ORCID: 0000-0002-1243-4434;

² ORCID: 0000-0003-4910-6239;

¹ Irkutsk state University, Irkutsk, Russia;

² Monolit LLC, Irkutsk, Russia

* Corresponding author (gamlet421[at]yandex.ru)

Abstract

The article discusses the rationale and key reasons for gold mining in dumps and tailings. In Russia, it is necessary to increase gold production at already developed deposits by using dumps and tailings to extract gold without involving in the development of new deposits. The resources of the dumps contain gold and can be used as a new type of raw material. The main stages of using the technology of extracting fine and thin gold from the waste products of the deposit are highlighted. The authors investigated the practical application of the technology for extracting fine and thin gold from waste products based on segregation-diffusion concentration in gold recovery factory at the «Vysochaishy» deposit in the Irkutsk region.

Keywords: fine and thin gold, concentrate, gold ore, waste rocks, segregation-diffusion concentration.

Introduction

The gradual formation of the gold and foreign exchange reserves of our country, associated with an increase in gold mining, is one of the most relevant areas for the development of technology in our country. For a long time, there has been a decline in alluvial gold production in Russia, despite its rich mineral resource base.

For many decades, rather simple in terms of geological structure, rich and easily enriched placers were intensively exploited; investments in exploration work have been significantly reduced, and, finally, the share of small, refractory gold has increased. Solution of the problem of developing old dumps, stale tailings, man-made gold placers expands the mineral resource base without involving new deposits in development. Additional recovery of fine gold from enrichment tailings is effectively, since the costs of stripping, mining, delivery of sands to the washing plant are excluded, in addition. It is necessary to consider the resources of deposits containing a lot of fine and thin gold as a new type of raw material for which there is no effective enrichment technology with a high recovery. Solution of the technical and chemical problems of the gold mining industry is the rejection of outdated technologies designed for the almost disappeared category of large gold.

Table 1 – The content of fine gold in the final products of enrichment [1], [2], [3]

waste products of gold mining	Fine hammer content, mg/m3
	Min	Max
ephel dumps	70	400
pebble dumps	60	280
sluice tails up		6000
dredge dumps	120	300

 

It is necessary to switch to introduction of new chemical technology [4], modern environmentally friendly technology that ensures the extraction of a very thin precious gold metal. The basis for solving the problem of increase in production of alluvial gold mining is the introduction of new equipment and chemical technology to increase the extraction of fine and thin gold.

Research methods

In the during the study, the following research methods were used:

1) magnetic-radiometric, chemical methods of analysis of initial materials and separation products;

2) analytical and experimental studies of the main parameters of the operation of segregation-diffusion concentrator.

The segregation-diffusion concentration makes it possible to extract fine grades of gold up to 5 µm in size. After enrichment at locks (Lyashenko effect) equal incidence, with a ratio of gold density to quartz (SiO2) density close to 10, quartz (SiO2) particles in ephels turn out to be much larger than gold particles. The size of the channels between the particles is on average 0.1 part of their diameter, which allows the gold grains to seep through the quartz layer [9].

The segregation-diffusion concentrator was developed by the STC Mining and Processing Plants of the Moscow State Mining University (STC MSTU). The installation allows to obtain concentrates containing several kilograms of gold per ton. How the concentrator works [10]:

1) Loading material. At the segregation-diffusion concentration, the weight of the material (middle product, tailings) was 1.5 kg. The material is loaded into the working area of the concentrator immediately; instead of the auger, looseners mounted on the shaft were used.

2) Bay of water and loosening of the material. After loading the material, water was supplied from the conical part of the concentrator, then the rippers were started by means of an electric drive. The number of revolutions of the rippers varied from 3 to 18 min. The amount of water supplied to create a fluidized bed is from 15 to 35 l/h per 1 kg of processed material. The period of operation of the installation is 60 minutes.

3) Extraction of material. Upon completion of the operation of the concentrator, the shaft with rippers was carefully removed, then the material was removed from the working area, which was divided into several parts: concentrate (1/4), middlings (1/2), tailings (1/4).

4. Draining water and drying the material. After draining the water, the concentrator products were dried at a temperature of 105°C.

Research results

As the main samples, the enrichment products of the «Vysochaishy» gold mill were used; they were represented by middlings and tailings of the gravity processing of the gold recovery plant, respectively, with a gold content of 798 g/t and 9.3 g/t, silver 1129 g/t and 32.28 g/t. The mineral composition of middlings and tailings is practically the same. The composition of middlings and tailings includes the following heavy minerals: arsenopyrite (FeAsS) – 50-60%; galena (PbS) – 30%; pyrite (FeS2) – 20%.

Analysis of the granulometric composition of the tailings of the «Vysochaishy» gold mill in the source material showed that 92% of the material was in the class – 0.2 mm, and 70% in the class – 0.1 mm, and in the middling product 95% of the material was in the class – 0.25 mm, 82% in the class – 0.2 mm and 40% in the class – 0.1 mm [5].

Table 2 – Granulometric composition of samples

Class, mm	Material 1, %	Total yield, %	Material 2 %	Total yield, %
+0,4	0	0	0	0
-0,4+0,25	3,84	3,84	0	0
-0,25+0,14	19,2	23,04	11,06	11,06
-0,14+0,1	35,64	58,68	24,09	35,15
-0,1+0,071	23,51	82,19	30,02	64,17
-0,071+0,063	8,99	91,18	14,94	80,11
-0,063+0,05	5,44	96,62	12,43	92,54
-0,05+0	3,38	100	7,47	100

According to the particle size distribution curves, it can be seen that the material consists mainly of small classes

During the tests, the sample weight was 3 kg, the vibration frequency was 100 Hz, the amplitude was 1 mm, the water consumption was 6-8 liters per concentration cycle, which was 20 minutes in time. After the concentration was completed, the supply of power and water was stopped, the vibrator was turned off, the lower part with the heavy fraction accumulator was disconnected from the concentrator, the products were washed off, dried, weighed, and dispersed for sieve analysis.

The resulting material in the form of a concentrate and tailings was sent to assay and analytical laboratory (AAL) for assay analysis.

According to the results of the assay analysis of the enrichment products of the middlings of the «Vysochaishy» gold mill, it was found that the extraction of gold into concentrate was 86.7% with a content of 9390 g/t. Extraction of the gold concentration from the tailings of the refinery was 84% with a gold grade of 98 g/t.

The obtained results of studies on the segregation-diffusion concentration proved the effectiveness of the segregation-diffusion method, and the obtained separation characteristics of the concentrator operation made it possible to conclude that the chemical method is highly effective in separating refractory fine and fine grades of gold.

Table 3 – Results of tests of the segregation-diffusion concentrator on waste products of the «Vysochaishy» deposit

Sample type	Concentrate yield, %	Content heavy.fractions in to-those, g/t	Extraction of heavyfractions in to-t, %
Middlings product	~ 3,4	9390	86,7
Tailings	~ 3,5	98	84

 

The use of segregation diffusion concentration will increase the recovery of fine and fine gold in waste products, additional extraction of a valuable component from intermediate products and tailings of gold recovery plants.

As a result of the operation of the segregation-diffusion concentrator, five products were obtained. Each concentrator product was divided into two parts: for particle size distribution and for assay analysis. According to the results of the assay analysis of the enrichment products of the «Vysochaishy» gold mill middling product, it was found that the extraction of gold into concentrate was 82% with a content of 6040 g/t. The extraction of gold concentration from the tailings of the refinery was 91.4% with a grade of 15.8 g/t. [6], [7], [8]

Implementation of the segregation-diffusion – method and equipment at technogenic placer deposits of the gold mining industry and gold mining tailings in only one season allows (per 1 segregation-diffusion concentrator):

1. With a gold content in dumps of 0.5g/t and an extraction of 50%, it allows to extract 10-11 kg of gold at a cost of $5, which makes it possible to obtain high profitability of the segregation-diffusion concentration technology;

2. To reduce the content of mercury (Hg) in man-made dumps and soil by 90%, and bring up to 200 000 m³ of sand to sanitary standards (reduction of mercury from 0.2 g/m³ to 0.001 g/t) to extract up to 40 kg of mercury (Hg).

3. Land reclamation after the complete extraction of gold and toxic additives allows (Hg) them to be returned to economic circulation.

4. Reduce the mercury (Hg) content in local reservoirs and rivers adjacent to gold mining sites from 0.2 g/m³ to sanitary standards.

Conclusions and recommendations

1. The possibility of implementing a new process of segregation-diffusion -concentration of fine and thin gold from waste products of gold mining has been proved, its main theoretical regularities have been established;

2. A new technology for the enrichment of metal-bearing sands with a high content of fine and thin gold has been proposed, which makes it possible to significantly increase the efficiency of the gold enrichment process by reducing its losses;

3. The introduction of new chemical processes and devices of segregation-diffusion concentration in the industry will significantly expand the raw material base of alluvial gold mining at the expense of man-made deposits with a high content of fine and thin gold, for example the «Vysochaishy».

Конфликт интересов  Не указан.

Conflict of Interest  None declared.