WO2013128254A1

WO2013128254A1 - System for gold recovery and processing

Info

Publication number: WO2013128254A1
Application number: PCT/IB2012/056947
Authority: WO
Inventors: Jaime Enrique MICHEA PONCE
Original assignee: Universidad Católica Del Norte
Priority date: 2012-02-29
Filing date: 2012-12-04
Publication date: 2013-09-06
Also published as: CL2012000542A1

Abstract

The invention relates to a system for gold recovery and processing (100), which has a compact and efficient design that enables a reduction in time and energy consumption of the plant, and which provides an environmentally friendly solution by avoiding the use of reactive chemicals, wherein said system comprises: a crusher (101) and a high impact mill (102), combined in such a manner that both share the same actuating means; a magnetic separator (103) of permanent magnets that magnetically separates sterile material and pre-concentrated material; a tank mixer (104) in which the pre-concentrated material is mixed with water to form a pulp; at least one concentrator that receives the pulp and processes it in order to obtain mineral-rich concentrate; a residue separator (107) that receives tailings coming from at least one concentrator, enabling the separation of residues and water; a centrifugal concentrator (108) that receives the water from the residue separator (107), enabling the recovery of the fine particles of gold present in the water, and combining said particles with the rich concentrate coming from at least one concentrator; and a tilted melting furnace (109) that receives and processes the rich concentrate from at least one concentrator and the fine particles from the centrifugal concentrator (108); wherein in another outlet of the centrifugal concentrator (108) recycled water, which is processed by a filtration plant (110) and is purified, exits to be reused in the tank mixer (104).

Description

GOLD RECOVERY AND PROCESSING SYSTEM

SCOPE

The present invention relates to the gold mining and processing industry. In particular, the present invention consists of a gold recovery and processing system that has a compact, highly efficient design and does not use chemical reagents.

BACKGROUND

At present, gold recovery processes to obtain a mineral concentrate use amalgamation methods with mercury in the case of small mining, while medium and large mining use different processes that use cyanide. As is known, both mercury and cyanide are highly toxic.

Another less dangerous method that is equally used for the recovery of gold is flotation, however, this process requires the use of multiple chemicals, which causes the process to be highly polluting and with very high costs.

In addition, the efficiency of all these methods is very relative, since it can vary between 40 to 70%, where the reason is because the processes must be very well calibrated, or else there would be severe losses, which it would raise costs considerably.

Gold recovery processes can be carried out using gravitational concentration equipment, using centrifugal concentrators such as the Knelson, Falcon or JIG concentrator. These concentrators provide several advantages that allow the recovery of ore efficiently. However, in the current state of the art, in order to process relatively high amounts of mineral concentrates, the processes are complex and use a large number of equipment and process steps. Which leads to considerable production and maintenance costs. An example of the above is described in patent document number WO 2009/039559 A1, which discloses a modular mineral processing system for mineral concentrates that can be used in underground units or tunnels of mines, in order to of concentrating the minerals before they need to be brought to the surface. Said system comprises a plurality of separate modules constructed to be arranged in series so as to form a feed processing system for the concentration of a desired material in the ore, wherein the modules are individually transportable to a processing site to be operatively united and form the modular ore processing system.

However, the system described in the previous document corresponds to a fairly complex and not very compact system, where the problem associated with the complexity of the system is solved through a modular design that can be assembled on site. The complexity of the system, and given the large number of elements that it comprises, leads to high energy consumption, which therefore results in high operating and maintenance costs. In addition, the system described in this document uses flotation, among other processes, so it also requires the use of chemical elements that pollute the environment.

In this way, there is a need in the state of the art for a milling and concentration system to process gold that has a compact and efficient design, allowing a decrease in time and energy consumption of the plant, thus reducing the costs associated with the recovery process, and providing an environmentally friendly solution by avoiding the use of contaminating chemical reagents.

To remedy the problems presented, a gold recovery and processing system is presented, with pressurized gravimetric concentration of continuous pulsation and tilt casting furnace, which allows gold to be processed without the use of chemical reagents. This system uses only water in a very low quantity, since it is constantly recycled during the process of obtaining gold.

The system is subdivided into four stages, where the first stage corresponds to grinding, comprising a crusher and an impact mill, both joined as a "duplex" system, sharing a single drive means. The second stage corresponds to the pre-concentration, which comprises a magnetic separator that allows the material to be magnetically separated. The third stage corresponds to the concentration, wherein said material from the magnetic separator is mixed with water in a mixer to form a homogeneous pulp, this being driven to concentrators to allow obtaining a mineral-rich concentrate. In addition, at this stage the system comprises a waste and water separator, which receives the tails from the concentrators to separate them into waste and water, where the waste leaves the system and the water enters a centrifugal concentrator that allows recovery the fine gold particles present in the water, so that said fine particles finally bind with the result of concentrator concentrates. Finally, the fourth stage corresponds to the smelting, in which the concentrates of the concentrators and the centrifugal concentrator are discharged, and loaded into a tilting smelting furnace with ingot mold, with which once the smelting is finished the ingot doré is delivered . At the other outlet of the centrifugal concentrator, recycled water comes out, which is clarified and filtered to be reused in the mixer.

The system has the comparative advantage that both the crusher and the impact mill use the same drive means for both processes, achieving a decrease in energy consumption and time, since it prevents, for example, the transportation of the grinding.

In addition, the water used to form the homogeneous pulp is processed after its passage through the centrifugal concentrator so that it is again sent to said centrifugal concentrator.

On the other hand, an important advantage is that the system does not leave residues, since both the sterile material and the residues that leave the system have added value, being perfectly marketable.

The present invention throughout its process does not use any chemical reagent, but only water, where the latter is also recycled during the process. In addition, the present invention maximizes energy efficiency through the use of a single drive means and a transmission system that moves all System Components. Consequently, the above characteristics imply that not only the operating and maintenance costs are lowered considerably, but also an efficient and environmentally friendly solution is provided, where the system can achieve an efficiency in recovering gold from Up to 90%.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a diagram of the gold recovery and processing system according to a preferred configuration of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, and as can be seen in Figure 1, the present invention consists of a gold recovery and processing system (1 00), which has a compact and efficient design allowing a decrease in time and energy consumption of the plant. Said system comprises:

a crusher (1 01) and a high impact mill (1 02), which share the same drive means;

a magnetic separator (103), which magnetically separates sterile material and pre-concentrated material;

a mixing tank (1 04), wherein the pre-concentrated material is mixed with water to form a pulp;

at least one concentrator, which receives the pulp and processes it to obtain a concentrate rich in mineral;

a waste separator (107) that receives queues from at least one concentrator, allowing waste and water to be separated;

a centrifugal concentrator (08) that receives water from the waste separator (107), allowing fine particles of gold present in the water to be recovered, and joining said recovered particles to the rich concentrate from at least one concentrator; Y

a tilting smelting furnace (109) that receives and processes the rich concentrate from at least one concentrator and the fine particles of the centrifugal concentrator (108); where in another outlet of the centrifugal concentrator (108) recycled water comes out, which is processed by a water filtration and clarification plant (1 10), to be reused in the mixing tank (1 04). In a preferred configuration of the invention, the system comprises a first concentrator (1 05) and a second concentrator (106), arranged in series, whose mineral-rich concentrate is joined to be sent to the smelting furnace (109). In addition, the concentrator (1 05, 106) may be selected from a group comprising: Dember, Valtar, Yuba, Geko or other concentrators. However, a preferred configuration of the invention considers the use of pulse concentrators J IG with continuous and pressurized vibration. In addition, the magnetic separator is preferably permanent magnets.

Preferably the crusher (101) uses a differentiated shock absorber, causing the rock to disintegrate avoiding excessive grinding. This allows to obtain a more efficient and faster grinding, achieving the elimination for example of "laminar gold" or gold in "flakes" (which is normally produced with the use of other mills, such as: mill, balls, bars, de cones, mortars, rammers, etc.). In this sense, it is important to keep in mind that the presence of "laminar" gold prevents its recovery, managing to escape from other processes.

In addition, as mentioned, the system comprises a water filtration and clarification plant (1 1 0), connected to an outlet of the centrifugal concentrator, such that it uses the water coming from said centrifugal concentrator (1 08) and the It processes in such a way that it leaves it in a position to be reused in the mixing tank (104).

In an alternative configuration of the invention, more than one system can be joined, working in parallel, in such a way to form a "productive module" that can reach 200 tons per day, multiplying production and reducing costs considerably, Because this configuration allows that in case one of the systems is paralyzed (either by maintenance or some failure), the metal production does not stop. The raw material enters the crusher (101) and the high impact mill (1 02) in such a way that the result of high impact grinding produces a final rock size of about 2 mm. Subsequently, during the passage of the mineral through the magnetic separator (1 03) of permanent magnets, the pre-concentrated material from the high impact mill (1 02) falls by gravity to the mixing tank (104), where said material is mixed with water forming a homogeneous pulp of material with water, and where said pulp is sent through a first pump (1 13) to the first concentrator (105). Thus, in the first concentrator (1 05) the material containing high concentration of ore is separated by specific weight, being stored in a place of concentrate within the first concentrator. Material containing a lower concentration passes to the second concentrator (1 06) for the recovery of additional valuable material.

In this way, the pre-concentrated material enters the concentrators (1 05, 106) J IG at high pressure, where it is received by a pulsating bed, which drives fine material into a pressurized atmosphere, avoiding the loss of laminar gold. At a later stage, the pulp of light material, or glue, which comes as waste from the second concentrator (106), passes through the waste separator (107), where said pulp is separated into waste (1 1 1) leaving the system and water entering the centrifugal concentrator (108). The centrifugal concentrator (108) manages to increase the specific gravity of the fine mineral particles, allowing the separation of the fine particles from the water. Thus, the concentrates of both concentrators (1 05, 106) are combined with the result of the centrifugal concentrator, which is rich in ore, to pass to the smelter and finally obtain the Doré.

At the other outlet of the centrifugal concentrator (108), recycled water comes out, which is sent through a second pump (1 14) to the water filtration and clarification plant (1 0 0), where the water is processed in such a way to leave it suitable to be re-entered into the system in the mixing tank (1 04).

During the passage of material through the magnetic separator, in which the system magnetically separates the sterile material from the valuable one, the volume of the material to be processed is drastically reduced, with the consequent cost savings involved. In addition, the pressurized gravimetric concentration of pulsation with continuous vibration, achieved through the J IG concentrators, optimizes the concentration in such a way that it is not necessary to use any other process for the recovery of valuable material, but after the exit of the concentrators the material can go directly to the foundry.

In addition, preferably the invention comprises a single drive means and a mechanical transmission system that drives all the components of the system using a single drive means, such that energy efficiency is maximized while operating costs are reduced and maintenance, allowing also to replace the use of electric generation and electric motors.

In this way, the system comprises a single drive means, preferably a stationary diesel engine, to which a vibration dissipator and torque strokes are attached to its main axis, and which includes 4 double pulleys, allowing the crusher to be operated ( 1 01), the high impact mill (102) and the magnetic separator (1 03), in turn that additionally drives 2 transmission shafts. The first transmission shaft allows the mixing tank (1 04) and the second pump (1 14) to be operated, while the second transmission shaft allows the concentrators (105, 106), the waste separator (1 07), concentrator to be operated centrifugal (1 08), and the first pump (1 1 3). The set of different movements and forces, works smoothly and harmoniously, thanks to the dissipation of vibrations, strategically located as a whole.

As a consequence of the above characteristics, it can be seen that the present invention provides a highly efficient solution that minimizes the consumption of inputs such as water, fuel and electrical energy, thanks to the configuration of the system elements, and the system of drive and transmission previously described. The following comparative tables show the levels of consumption of the mentioned variables to produce a gram of gold, with the present invention and a conventional state-of-the-art plant. WATER CONSUMPTION

Conventional system Present invention

Liters per day 7000 400

Liters per month (24 business days) 168000 9600

Tons per day 50 50

Liters per ton 140 8

Head Law Au (grs.) / Ton 6 6

System efficiency 50% 90%

Grams of gold per ton 3 5.4 of the system

Liters per gram of Gold 46.67 1.48

Cost per liter ($ / liter) 1.5 1.5

Water expenditure per gram of $ 70.00 $ 2.22 gold produced

FUEL CONSUMPTION (DIESEL)

Conventional system Present invention

Liters per day 200 70

Liters per month (24 business days) 4800 1680

Tons per day 50 50

Liters per ton 4 1.4

Head Law Au (grs.) / Ton 6 6

System efficiency 50% 90%

Grams of gold per ton 3 5.4 of the system

Liters per gram of Gold 25.9 1.54

Cost per liter ($ / liter) 640 640

Diesel expenditure per gram of $ 474.0 $ 165.9 gold produced

ENERGY CONSUMPTION

Conventional system Present invention

Watts per day 400,000 0

Watts per month (24 business days) 9,600,000 0

Tons per day 50 50

Watts per ton 8,000 0

Head Law Au (grs.) / Ton 6 6

System efficiency 50% 90%

Grams of gold per ton 3 5.4 of the system

Watts per gram of Gold 2,666 0

Cost per Watt $ 0.32 640

Expense in Watts per gram of $ 853 0 gold produced Consequently, it follows from the previous tables that the global cost (which considers water, electricity and fuel costs) associated with the production of a gram of gold, through a conventional system in the prior art, is $ 1357; While using the present invention, the overall cost for each gram of gold produced is reduced to $ 168, that is, a decrease in production costs of up to 88% can be obtained.

Claims

A gold recovery and processing system (100),

CHARACTERIZED because it includes:

a crusher (101) and a high impact mill (102), joined in such a way that both share the same drive means;

a magnetic separator (103) of permanent magnets, which magnetically separates sterile material and pre-concentrated material;

a mixing tank (104), wherein the pre-concentrated material is mixed with water to form a pulp;

a centrifugal concentrator (108) that receives the water from the waste separator (107), allowing to recover the fine gold particles present in the water, and joining said particles to the rich concentrate from at least one concentrator; Y

a tilting smelting furnace (109) that receives and processes the rich concentrate from at least one concentrator and the fine particles of the centrifugal concentrator (108);

where in another outlet of the centrifugal concentrator (108) recycled water comes out, which is processed by a water filtration and clarification plant (1 10), to be reused in the mixing tank (104).

The gold recovery and processing system according to claim 1, CHARACTERIZED in that it comprises a first concentrator (105) and a second concentrator (106), arranged in series, whose mineral-rich concentrate joins to be sent to the smelting furnace (109). The gold recovery and processing system according to claim 1, CHARACTERIZED because the at least one concentrator can be selected from a group comprising: JIG, Dember, Valtar, Yuba or Geko concentrators.

The gold recovery and processing system according to claim 3, CHARACTERIZED in that the at least one concentrator corresponds to a pulsed JIG concentrator with continuous and pressurized vibration.

The gold recovery and processing system according to claim 1, CHARACTERIZED in that the crusher (101) uses a differentiated shock absorber.

The gold recovery and processing system according to claim 1, CHARACTERIZED because it comprises a transmission system that moves all system components using a single drive means.

The gold recovery and processing system according to claim 6, CHARACTERIZED in that the drive means corresponds to a diesel engine, which comprises a vibration and torque shock dissipator, and is operatively connected to the transmission system.

The gold recovery and processing system according to claim 6, CHARACTERIZED in that the transmission system comprises four double pulleys, which allow the crusher (101), the high impact mill (102) and the magnetic separator (103) to be operated. , in turn that additionally drives two transmission trees; wherein the first transmission shaft allows the mixing tank (104) and the second pump (1 14) to be operated, while the second transmission shaft allows the concentrators (105, 106), the waste separator (107), concentrator to be operated centrifugal (108), and the first pump (1 13).