WO2023084471A1

WO2023084471A1 - Method and system for extracting gold without chemicals

Info

Publication number: WO2023084471A1
Application number: PCT/IB2022/060902
Authority: WO
Inventors: Daniel BELLOFATTO
Original assignee: Bellofatto Daniel
Priority date: 2021-11-13
Filing date: 2022-11-13
Publication date: 2023-05-19
Also published as: IT202100028175A1

Abstract

A chemical-free gold extraction system has gold-containing ore crushing means, ore grinding means, a first gravimetric separator (10) and a second gravimetric separator (16) to provide, respectively, a first gold concentrate (C1) and a second gold concentrate (C2). The system is installed on a general frame and includes a so-called RUNNER 3000 machine (17) designed to replace the use of cyanide and obtain a third gold concentrate (C3), and a so-called GOLD PARTICLE SEPARATOR machine (18) designed to replace the use of mercury to obtain 21-23 carat refined gold from the aforementioned gold concentrates. A method of crushing, grinding and gravimetric separation of the mineral in order to extract the gold particle without the use of chemical is also described.

Description

[0001 ] Title of the invention: METHOD AND SYSTEM FOR EXTRACTING GOLD

WITHOUT CHEMICALS

Field of the invention

[0002] The present invention relates to the gold extraction field.

[0003] In particular, the present invention refers to a system installed on a general frame on which in turn all the apparatuses and connections of process water, waste water and electricity are mounted.

[0004] The invention also relates to an extraction method comprising the crushing, grinding and gravimetric separation of ore containing gold, without the use of chemicals such as mercury and cyanide. The method uses only recycled and closed-circuit water.

[0005] The system for carrying out the method includes, among other apparatuses, a machine, hereafter called RUNNER 3000, which does not require the use of cyanide, and a machine, hereafter called GOLD PARTICLE SEPARATOR, which does not require the use of mercury.

Background Art

[0006] Artisanal gold extraction employs millions of people who benefit from the positive effects of this activity that shapes and improves the structure of the economy and rural families. However, to date the method used in countries where gold is extracted, especially in Third World Countries, is precarious, unpredictable, largely informal, and uses highly dangerous chemicals, such as mercury and cyanide, which are harmful to the health of gold miners and the environment. In particular, the manual procedures for gold extraction are known today, some machines are known that grind and crush the ore.

[0007] CN112742593 A describes a gold ore enrichment method that involves crushing raw ore until the particle size is below 15 mm, then carrying out coarse grinding, controlling the grinding fineness of the grinding to be below 0.074 mm in a proportion of 45-60% by weight, then carrying out rough concentration to obtain centrifugal rough concentrate and centrifugal tailings, carrying out fine grinding on the obtained centrifugal rough concentrate, carrying out rough and fine flotation for obtaining a concentrate, wherein the grinding fineness is controlled to be below 0.074mm in a proportion of 80-85 wt%.

[0008] CN112844816 A describes a method of reselection and regrinding of Knelson centrifugated concentrates in a Knelson separator, and an equipment for their treatment.

[0009] CN108380381 A discloses a gravimetric concentration device and a method for gold ore of the type in large and medium granularity quartz vein.

[0010] WO2013/128254 discloses a system for the recovery and treatment of gold that allows a reduction in time and energy consumption, and provides an environmentally friendly solution, avoiding the use of reaction chemicals.

Summary of Invention

[0011] An object of the invention is to use a method for primary gold ore with microfine particles and with a high total recovery rate, in particular a method that has a yield at least 30% more than the artisanal currently used method.

[0012] Another object of the invention is to provide a method of ore crushing, grinding and gravimetric separation in order to extract the gold particle with a closed circuit system that allows to eliminate harmful chemicals in accordance with the UN recommendations and also permits a use of waste water with significant savings in economic and environmental terms on water consumption.

[0013] A general object of the present invention is to solve the aforementioned problems in the prior art by providing a gold extraction system that carries out a method based on the use of two machines, the so-called RUNNER 3000 machine designed to replace the use of cyanide and the so-called GOLD PARTICLE SEPARATOR machine designed to replace the use of mercury.

[0014] Another object of the present invention is that the method works in a closed circuit thus also ensures reliably that the gold particle is visible only at the end at the moment of the direct melting that takes place in a closed room with maximum security.

[0015] A further object of the present invention is to eliminate the exploitation currently existing of the work of women and children and to replace their work with a fully mechanized method that allows maximum and effective control also in terms of the actual quantity and weight of the extracted and worked material.

[0016] The aforesaid and other objects and advantages, as will emerge from the following description, are achieved by the invention which, in a first aspect thereof, provides an system for gold extraction without chemicals, the system comprising crushing means for ore containing gold, means for grinding the same ore after crushing, a first gravimetric separator and a second gravimetric separator adapted to provide, respectively, a first gold concentrate and a second gold concentrate of the same ground mineral.

[0017] The system is installed on a general frame on which said means, said gravimetric separators and process water, wastewater and electricity connections are mounted.

[0018] The system also includes a so-called RUNNER 3000 machine, computerized and totally managed by artificial intelligence, including an agitator reactor, able to receive tailings from the second gravimetric separator, an outlet duct from the agitator reactor, an ejection box for the tailings at the outlet of the agitator reactor, a plurality of advancing and vibrating bands, on the first of which the ejection box is able to project the tailings, a respective plurality of gutters underneath the plurality of advancing and vibrating bands, equipped with rinsing devices with water and connected with respective drain pipes, a recovery tray for a third gold concentrate and a collecting tank for a mixture of tailings and water falling into the gutters from the advancing and vibrating bands.

[0019] The system also includes a so-called GOLD PARTICLE SEPARATOR machine totally managed by artificial intelligence and automated, including an upwardly converging frustoconical compartment, which is equipped at the bottom with an agitator above a gold particle recovery drawer and a blower and extends upwards in a chimney with the upper end that is open and spaced by an interspace from a frustoconical passage downwards destined to be crossed by said first gold concentrate, second gold concentrate and third gold concentrate to be separated, the interspace being affected by a jet of compressed air obtained with a tube ending with a flute-beak end facing a channel communicating with a receptacle for the recovery of concentrate particles.

[0020] In a second aspect, the invention provides a method for gold extraction without chemicals, comprising a first step of crushing gold particle containing ore to be reduced from a maximum size of 70 mm to a maximum size of 30 mm, a second crushing phase from a maximum size of 30 mm to a maximum size of 6 mm, a first gravimetric separation with separation of particles with a maximum size of 0.07 mm to obtain a first gold concentrate, a grinding phase to grind the particles by reducing them from a maximum size of 3 mm discarded in the first gravimetric separation to a maximum size of 0.5 mm, a second gravimetric separation with separation of particles with a maximum size of 0.07 mm, to obtain a second gold concentrate, in which a third separation of the tailings is carried out by means of a so-called RUNNER 3000 machine without the use of cyanide to obtain a third gold concentrate.

[0021] The so-called RUNNER 3000 machine performs the following steps: aqueous mixing of the tailings from the second gravimetric separation in an agitator reactor, expulsion of the pressurized aqueous mixture through a box equipped with ejection holes on each advancing and vibrating band on which the gold particles are trapped in the fibres, detachment of the gold particles and their subsequent fall into the underlying gutters through the rinse nozzles to obtain the third gold concentrate in the recovery tray.

[0022] The so-called GOLD PARTICLE SEPARATOR machine performs the following steps:

[0023] insertion of the first gold concentrate, the second gold concentrate and the third gold concentrate by gravity from above in the frustoconical passage, pushed upwards of the light particles by means of pressure and vortex agitation obtained from agitator and blower, diverting the light particles into the ore particle recovery receptacle, and collecting the heavier weight gold particles in the gold recovery drawer.

Brief Description of Drawing

[0024] The present invention will be described in detail in the following with reference to the attached drawings, in which:

[0025] [Fig.1] [Fig.1] is a flow chart representing a system for gold extraction according to the present invention;

[0026] [Fig.2] [Fig.2] is a schematic side view of the so-called RUNNER 3000 machine which replaces the use of cyanide in the method according to the invention;

[0027] [Fig.3] [Fig.3] is a schematic vertical section of the so-called GOLD PARTICLE

SEPARATOR machine which replaces the use of mercury in the method according to the invention.

Description of an Embodiment of the Invention

[0028] Reference is initially made to [Fig.l] which is a flow chart representing a system for gold extraction according to the present invention.

[0029] For each ore to be treated, a preliminary study of the material is required which consists of a particle size examination or particle size analysis. This exam is currently applied in the ore preparation, for the study of comminution products and natural incoherent materials such as gravel and sand. In fact, the gold content is closely linked to the sedimentological features and the grain size of the deposit. Its increase is due to the increase in the size of the metal particles. Since gold is mainly contained in the basic coarse sediment and is concentrated, upon contact with the bedrock, in localized "pay gravels", it is evident that the approach to crushing and grinding, as regards the dimensions of the pieces of ore must be related to the granulometric examination. For this reason, the measurements given below to the ore pieces and particles with reference to the type of treatment to be performed are only indicative and depend from time to time on the ore treated.

[0030] For example, be assumed that the gold ore pieces have an average size of 70 mm in diameter.

[0031] In [Fig.l], a first hopper is indicates as 1, a first vibrating feeder as 2, a jaw crusher as 3. The gold ore is discharged into the first hopper 1, and from here into the first vibrating feeder 2 to be then inserted into the jaw crusher 3. From this first crushing the gold ore is reduced on average to about 30 mm in diameter.

[0032] A first conveyor belt is indicated as 60, a second hopper as 5, a second vibrating feeder as 6, a cone crusher as 7, a second conveyor belt as 61 and a vibrating sieve with washing as 9.

[0033] The gold ore is transported by the first conveyor belt 60 into the second hopper 5, from which it descends into the second vibrating feeder 6 to end up in the cone crusher 7. At the exit of the cone crusher 7, the gold ore is made to advance on the second conveyor belt 61 up to the vibrating sieve with washing 9. The vibrating sieve with washing 9 performs a granulometric separation of the mineral coming from the cone crusher 7 in a first outlet Ei of first particles with a diameter Ri <2 mm, in a second outlet E2 of second particles with a diameter generally comprised between Ri and R₂ with R₂ < 6 mm and in a third outlet E₃ of third particles generally with a diameter R₃ > 6 mm. The latter, in order to ensure efficient separation, return to the second hopper 5 through a third conveyor belt 62.

[0034] Also in [Fig.1], a first gravimetric separator or Knelson type cup concentrator is indicated as 10, a ball mill as 11, a dehydration sieve or squeezer as 12, a receiving tank as 13, a hydrocyclone as 14, a fourth conveyor belt as 63, a second gravimetric separator or Knelson type cup concentrator as 16. The so-called RUNNER 3000 machine for the cyanide-free treatment is indicated as 17, and the so-called GOLD PARTICLE SEPARATOR machine for the mercury-free treatment as 18. These machines will be described in detail in the following.

[0035] The first gravimetric separator 10 has an inlet for the mineral, indicated by arrow 69 and connected to the Ei outlet of the vibrating sieve with washing 9 and a W₂ inlet for water. In addition, the first gravimetric separator 10 has a first collection 64 of gold concentrate Ci and an outlet U₂ for larger particles or tailings from the first gravimetric separator 10.

[0036] In operation, the first collection 64 of gold concentrate Ci goes to the so-called GOLD PARTICLE SEPARATOR 18 for mercury-free treatment, while the larger particles or tailings in the outlet U2 flow into a second duct 65 coming from the exit E₂ of the vibrating sieve with washing 9. The flow in the third duct 66 reaches the ball mill 11 where the grinding takes place up to a preferable size between 0.5 and 0.07 mm.

[0037] From the ball mill 11, the ground ore reaches the dehydration sieve 12. From here, through the fourth conveyor belt 63, the particles exceeding 0.07 mm are returned under the cone crusher 7 by the second conveyor belt 61 to pass through the vibrating sieve with washing 9.

[0038] The dehydration sieve 12 passes the most liquid part to the receiving tank 13. The hydrocyclone 14 separates the ore with a grain size greater than 0.070 mm by sending it through a third duct 66 to the inlet of the ball mill 11. The rest is sent to the second gravimetric concentrator 16 through a fourth duct 67.

[0039] The second gravimetric separator 16 has a W₃ inlet for water; in addition, it has a second collection 70 of gold concentrate C₂ and a U₃ outlet for tailings.

[0040] Similarly to the first gravimetric separator 10, the second gravimetric separator 16 brings the gold concentrate C₂ to the so-called GOLD PARTICLE SEPARATOR 18 machine. The tailings from the second outlet U₃ flows into a fifth duct 68 which leads to the so-called RUNNER 3000 machine for cyanide-free treatment.

[0041] With reference to [Fig.2], it shows the so-called RUNNER 3000 machine, marked with block 17 in [Fig.1]. Said machine does not require the use of cyanide.

[0042] The machine, computerized and totally managed by artificial intelligence, comprises, on a frame 37, an agitator reactor 23, a duct 24, an ejection box 25, a plurality of advancing and vibrating bands, three in number in the embodiment illustrated, indicated as 26, 27, 28 overlying a respective plurality of gutters 29, 30, 31 connected in succession by respective drain pipes 32, 33, and a collecting tank 34 and a recovery tray 39 for the gold concentrate C₃. The gutters are equipped with water rinsing devices, substantially nozzles generically indicated as 38.

[0043] An aqueous mixture of ground ore at 0.070 - 0.075 mm, consisting of 75% solid and 25% water, enters the agitator reactor 23 according to an arrow F.

[0044] The operation of the so-called RUNNER 3000 machine is as follows. The aqueous mixture in the agitator reactor 23 is stirred and expelled under pressure according to the arrow G through a duct 24 which leads to an ejection box 25 equipped with ejection holes.

[0045] The aqueous mixture, which is pressurized, is sprayed from the ejection box 25 onto a first advancing and vibrating band 26 which advances according to the arrow VI, towards the right in [Fig.2]. The carpet of the advancing and vibrating band 26 traps the gold particles in its fibres thanks to its vibrant movement. Below the advancing and vibrating band 26 there are water rinse nozzles 38 which cause the detachment of the gold particles and their subsequent fall into the underlying gutter 29. V_g indicates the direction of advancement in the gutter 29, and in the subsequent gutters 30, 31, 32 of the mixture of particles and water detached from the advancing and vibrating band 26, and from the subsequent advancing and vibrating bands 27, 28. The mixture falling from the advancing and vibrating band 26 into the underlying gutter 29 continues its flow: for one part, in a chute 35, which is placed on the lower end of the gutter 29 and allows the mixture to settle on the subsequent advancing and vibrating band 27; for the other part, in a drain pipe 32 which allows it to fall into the next gutter 30.

[0046] The advancing and vibrating band 27, which advances in the direction V ₂, towards the right in [Fig.2], carries the mixture on the advancing and vibrating band 28 which advances in the direction V₃, to the left in [Fig.2]. The aqueous mixture falling on the gutter 30 from the advancing and vibrating band 27 by the rinsing through the nozzles 38, falls on the gutter 31 through the drain pipe 33. Finally, the mixture arrives according to the arrow V_g through a tube 36 in the collecting tank 34, and the gold concentrate C₃ is deposited in the recovery tray 39 to be treated before moving onto the so- called GOED PARTICEE SEPARATOR 18 machine, which in its operation does not require the use of mercury.

[0047] With reference to [Fig.3], this machine, totally managed by artificial intelligence and automated, is a dry gravimetric separator specially designed to separate the gold particle from the rest. The separator comprises, inside a housing 40 supported on a support 50, a frustoconical compartment 41 extending upwards into a chimney 42 with an upper end 43, which is provided with a perforated septum 55 and is close to a frustoconical passage 44 convergent downward. The upper end 43 is tapered upward in order to create a Venturi effect. The separation gap 4 between the upper end 43 of the chimney 42 and the frustoconical passage 44 is affected by a jet of compressed air obtained with a pressured air pipe 45 ending with a flute -beaked end facing a channel 46 communicating with a receptacle 47 for the recovery of light particles. The frustoconical compartment 41 has an agitator 48, adjustable both in speed and in the direction of rotation, driven by an electric motor 49. Underlying the agitator 48 is a gold particle recovery drawer 51, which overhangs a blower 52. The conical compartment 41 is affected by a flow of hot air, indicated by arrow 53, and by a flow of cold air, indicated by arrows 54.

[0048] The operation of the so-called GOLD PARTICLE SEPARATOR machine, indicated as 18 in [Fig.l], is briefly described in the following. The gold concentrate to be treated, coming from the gravimetric separators or Knelson concentrators 10 and 16, as well as from the so-called RUNNER 3000 machine 17, is periodically introduced by gravity from above into the frustoconical passage 44. In virtue of the pressure and vortex agitation obtained by the agitator 48 and the blower 52, which is graduated and piloted, the light particles are pushed through the hot air stream 53 to the upper end 43 of the chimney 42 and are accelerated by Venturi effect. The cold air stream 54 pushes downwards gold particles that are heavier than the light particles. In the separation gap 4, thanks to the compressed air sent in the pressured air pipe 45, the light particles are diverted in the direction of arrow 56 into the container 47 for the recovery of the light particles. The heavier gold particles are collected in the gold particle recovery drawer 51.

[0049] Once separated with this machine, all the particles will be placed in the kiln for direct melting in order to obtain refined gold between 21 and 23 carats.

[0050] Referring to [Fig.l], the method substantially comprises the following steps:

[0051] - first crushing of pieces of ore containing gold particles, with the aim of obtaining pieces from about 0.5 to 30 mm;

[0052] - second crushing of the pieces of ore from about 0.5 to 30 mm to obtain particles of about 6 mm;

[0053] - first gravimetric separation of particles up to 2-3 mm with the use of the first cup centrifuge concentrator of Knelson type; [0054] - grinding, by using the ball mill, so that by grinding the pieces generally from 0.5 to

6 millimeters, particles suitably sized between 0.5 and 0.07 mm are obtained;

[0055] - second gravimetric separation of the particles having a size between 0.5 and 0.07 mm with the second cup centrifuge concentrator of Knelson type;

[0056] - third separation of tailings with the so-called RUNNER 3000 machine without the use of cyanide;

[0057] - separation of the concentrate after drying with the use of the so-called GOLD

PARTICLE SEPARATOR machine without the use of mercury;

[0058] - direct melting of the gold concentrate in the kiln, for example a Borel kiln, to obtain refined gold from 21 to 23 carats.

[0059] The following describes in detail how the ore crushing, grinding and gravimetric separation method works in order to extract the gold particle.

[0060] In crushing, the pieces of ore containing gold are discharged into the first hopper 1 or feed hopper to pass through the vibrating feeder 2 to the jaw crusher 3;

[0061] the jaw crusher 3 crushes the ore into pieces having dimensions up to about 30 mm, and the crushed ore falls directly onto the conveyor belt 60 to reach the second hopper or buffer hopper 5;

[0062] from the second hopper 5, the ore passes through the second vibrating feeder 6 to serve the cone crusher 7 and the ore is reduced mainly between 0.5 and 3 mm according to indications provided by the initial granulometric and mineralogical study;

[0063] from the cone crusher 7 the ore falls on the second conveyor belt 8 and goes to the vibrating sieve with washing 9. The particles not having the required diameter, generally greater than 6 mm, return to the cone crusher 7 to be crushed again and returned to the second conveyor belt 8;

[0064] the particles having a size of less than 6 mm are separated between those with a diameter of less than 2 mm, which are washed in the vibrating sieve with washing 8 and poured into the first gravimetric separator 10 or Knelson concentrator, and those that have a diameter up to 6 mm;

[0065] water is added to the particles with a diameter of less than 2 mm in the first gravimetric separator 10 to obtain an aqueous mixture of 35% of water and 65% of solid ore;

[0066] at the exit of the first gravimetric separator 10, there is, on the one hand, the first gold concentrate, called C_b which is received and stored in a closed box and brought to the so-called GOLD PARTICLE SEPARATOR 18 machine, described above, by the other hand, a mixture of ore and water, which flows together with the particles with a diameter up to 6 mm coming from the vibrating sieve with washing 9, into the ball mill 11;

[0067] the ball mill 11 rotates continuously and operates in a closed circuit with the de- hydration sieve 12 or squeezer, the receiving tank 13 and the hydrocyclone 14;

[0068] in the hydrocyclone 14 the ore is further ground to obtain ore particles from 0.5 mm to 0.07 mm, which go to the second gravimetric separator 16 or Knelson concentrator; particles having a size greater than 0.5 mm return to the ball mill 11;

[0069] in the second gravimetric separator 16, water is added to obtain an aqueous mixture of 35% of water and 65% of solid ore, as in the first gravimetric separator 10;

[0070] at the outlet of the second gravimetric separator 16 there is on the one hand the second gold concentrate, called C2, which is received and stored in a closed box and taken to the so-called GOLD PARTICLE SEPARATOR 18 machine, and on the other the mineral mixture / water that is sent to the so-called RUNNER 3000 17 machine for the gravimetric separation of ore without the use of cyanide, as previously described;

[0071] from the so-called RUNNER 3000 machine, the third gold concentrate, so-called C₃, is dried in the recovery tray 39 before passing to the so-called GOLD PARTICLE SEPARATOR 18 machine; the rest of the aqueous mixture goes to the collecting tank 34;

[0072] in this machine the light particles are transported by the centrifugal force in a vortex and discharged by the pressurized air stream into the receptacle 47 for the recovery of light particles;

[0073] once ejected from the so-called GOLD PARTICLE SEPARATOR 18 machine, the gold particles are placed in the kiln for direct melting in order to obtain refined gold between 21 and 23 carats.

[0074] An embodiment of the invention has been described, but of course it is susceptible to modifications and variations within the same inventive idea. In particular, numerous variants and modifications, functionally equivalent to the preceding ones, which fall within the scope of the invention as highlighted in the attached claims, will be immediately apparent to those skilled in the art.

Claims

[Claim 1] System for gold extraction without chemicals, comprising crushing means for ore containing gold, means for grinding the same ore after crushing, a first gravimetric separator (10) and a second gravimetric separator (16) both suitable to provide, respectively, a first gold concentrate (Ci) and a second gold concentrate (C₂) of the same ground ore, characterized in that the system:

- is installed on a general frame on which said means, gravimetric separators and process water, wastewater and electricity connections are mounted;

- includes a so-called RUNNER 3000 machine, computerized and totally managed by artificial intelligence, including an agitator reactor (23), suitable for receiving tailings from the second gravimetric separator (16), an outlet duct (24) from the agitator reactor (23), an ejection box (25) for an aqueous mixture with tailings exiting the agitator reactor (23), a plurality of advancing and vibrating bands (26, 27, 28), on the first of which the ejection box (25) is able to project the aqueous mixture with tailings, a respective plurality of gutters (29, 30, 31) underlying the plurality of advancing and vibrating bands (26, 27, 28), the plurality of gutters (29, 30, 31) being equipped with water rinsing nozzles (38) and being connected by respective drain pipes (32, 33), a recovery tray (39) for a third gold concentrate (C₃) and a collecting tank (34) for the mixture of tailings and water falling into the gutters (29, 30, 31) from the advancing and vibrating bands (26, 27, 28); and then,

- includes a so-called GOLD PARTICLE SEPARATOR (18) machine totally managed by artificial and automated intelligence, including a frustoconical compartment (41) converging upwards, which is provided at the bottom with an agitator (48) overlying a gold particle recovery drawer (51) and of a blower (52) and extends upwards into a chimney (42) with upper end (43), which is frustoconical upwards in order to create Venturi effect, open and spaced by a separation gap (4) from a frustoconical passage (44) convergent downwards, configured for a passage of said first gold concentrate (Ci), second gold concentrate (C₂) and third gold concentrate (C₃), the separation gap (4) being affected by a jet of compressed air obtained with a pressured air pipe (45) ending with a flute-shaped end facing a channel (46) communicating with a re- ceptacle (47) for the recovery of light particles.

[Claim 2] System according to claim 1, wherein the gold-containing ore crushing means comprises a first hopper (1), a first vibrating feeder (2), a jaw crusher (3), a second hopper (5), a second feeder vibrator (6) and a cone crusher (7), a first conveyor belt (60) connecting the jaw crusher (3) and the second hopper (2).

[Claim 3] System according to claim 2, wherein the means for grinding the gold- containing ore comprise:

- a vibrating sieve with washing (9), which has the inlet connected by a second conveyor belt (61) to the cone crusher (7), and a first outlet (Ei) towards the first gravimetric separator (10) whose first collection (64) of gold concentrate (Ci) goes to the so-called GOLD PARTICLE SEPARATOR machine (18), a second outlet (E₂) and a third outlet (E₃) for a return by means of a third conveyor belt (62) to the second hopper (5);

- a ball mill (11) connected to the second outlet E₂ of the vibrating sieve with washing (9) by means of a second duct (65), into which the tailings from the first gravimetric separator (10) also flows and, in a closed circuit, with a dehydration sieve (12) in communication with the first conveyor belt (61) by means of a fourth conveyor belt (63), with a receiving tank (13) and with a hydrocyclone (14), the hydrocyclone (14) separating the ore with a grain size greater than 0.070 mm which is sent through a third duct (66) to the entrance of the ball mill (11) from the rest which is sent to the second gravimetric concentrator (16).

[Claim 4] System according to claim 3, wherein the second gravimetric concentrator (16) has a fourth conduit (67) communicating with the hydrocyclone (14) for incoming ore, a second collection (70) of second gold concentrate (C₂) to be sent to the so-called GOLD PARTICLE SEPARATOR machine (18) and an outlet (U₃) for tailings to be sent to the so-called RUNNER 3000 machine through the fifth duct (68).

[Claim 5] System according to claim 1, wherein the frustoconical compartment

(41) is affected by a flow of hot air directed towards the chimney (42) and a flow of cold air directed towards the agitator (48).

[Claim 6] Method for the extraction of gold without chemicals, comprising a first phase of crushing of gold containing ore to be reduced from a maximum size of 70 mm to a maximum size of 30 mm, a second phase of crushing from maximum size of 30 mm to maximum size of 6 mm, a first gravimetric separation with separation of particles with maximum size of 0.07 mm to obtain a first gold concentrate (Ci), a grinding phase to grind the particles by reducing them from maximum size of 3 mm discarded in the first gravimetric separation to a maximum size of 0.5 mm, a second gravimetric separation with separation of particles with a maximum size of 0.07 mm, to obtain a second gold concentrate (C₂), characterized in that a third separation of the tailings is carried out by means of a so-called RUNNER 3000 machine without the use of cyanide to obtain a third gold concentrate (C₃), including an agitator reactor (23), suitable for receiving the tailings from the second gravimetric separator (16), an outlet duct (24) at the outlet from the agitator reactor (23), an ejection box (25) for an aqueous mixture of tailings exiting the agitator reactor (23), a plurality of advancing and vibrating bands (26, 27, 28), on the first of which the ejection box (25) projects the aqueous mixture of tailings, a respective plurality of gutters (29, 30, 31) underlying the plurality of advancing and vibrating bands (26, 27, 28), equipped with water rinse nozzles (38) and connected with respective drain pipes (32, 33), a collecting tank (34) and a recovery tray (39) for a third gold concentrate (C₃); the so-called RUNNER 3000 machine by performing the following steps:

- aqueous mixing of the tailings from the second gravimetric separation in an agitator reactor (23),

- expulsion of the pressurized aqueous mixture, through the ejection box (25) equipped with ejection holes, on each advancing and vibrating band (26, 27, 28) on which the gold particles are trapped in band fibres,

- detachment of the gold particles and their subsequent fall into the underlying gutters (29, 30, 31) through the water rinse nozzles (38) to obtain the third gold concentrate (C₃) that is deposited in a recovery tray (39) to be treated, and the rest goes into the collecting tank (34).

[Claim 7] Method according to claim 6, further comprising a separation of the first gold concentrate (Ci), the second gold concentrate (C₂) and the third gold concentrate (C₃) with the use of the so-called GOLD PARTICLES SEPARATOR machine, including a frustoconical compartment (41) converging upwards, which is provided at the bottom with an agitator (48) above a drawer for the recovery of gold particles and a blower (52), and extends upwards in a chimney (42) with the upper end (43), that is frustoconical upwards in order to create Venturi effect, open and spaced by a separation gap (4) from a frustoconical passage (44) convergent downwards, configured for a passage of said first gold concentrate (Ci), second gold concentrate (C₂) and third gold concentrate (C₃), the separation gap (4) being affected by a jet of compressed air obtained with a pressured air pipe (45) ending with a flute-shaped end facing a channel (46) communicating with a receptacle (47) for the recovery of light particles; the so-called GOLD PARTICLE SEPARATOR machine performing the following steps:

- insertion of the first gold concentrate (Ci), the second gold concentrate (C₂) and the third gold concentrate (C₃) by gravity from above in the frustoconical passage (44),

- pushing upwards light particles by pressure and vortex agitation obtained by the agitator (48) and the blower (52),

- diverting the light particles into the receptacle (47) for the recovery of light particles, and

- collecting gold particles heavier than the light particles in the gold recovery drawer (51).

[Claim 8] Method according to claim 6, further comprising the placing in the kiln of all the particles for direct melting in order to obtain refined gold between 21 and 23 carats.

[Claim 9] Method according to claim 8, characterized in that the method works in a closed circuit so that the gold particle is never visible except at the moment of direct melting which takes place in a closed room with maximum safety.