TECHNICAL FIELD

The present invention relates to a new pinched sluice machine which eliminates the problem arising from closer terminal velocities of finely sized valuable and gangue minerals in pulp medium due to low density difference between them, and which provides high efficiency in the concentration of low grade ores.

PRIOR ART

Gravity concentration, which is one of the oldest concentration methods, is based on separation of minerals according to density difference. (Burt, R. O., 1984. Gravity Concentration Technology. New York: Elsevier Science Publishing Company). By definition, concentration by gravity methods is the separation of particles in a mixture with different particle size, shape and density, from each other by means of gravitational and/or centrifugal force (Apian, F. F., 1985. Gravity Concentration - Introduction: in SME Mineral Processing Handbook. New York: Society of Mining Engineers).

Gravity concentration can be carried out by using jigging type and/or flowing film concentrators in addition to centrifugal type gravity concentrators. Jig is a separator where vertical pulsation is applied. Today’s commonly used flowing film concentrators are shaking tables and spirals. Another example of flowing film concentrators is pinched sluice. (Siyahhan and Ergun, 1999; Ergun and Ersayin, 2002; Yurtsever, 2016).

Pinched sluice is a flowing film concentrator used particularly for the concentration of low grade ores. Feeding is realized to the pinched sluice through the feeding point in a manner forming equal pulp height at every point of the surface. Pulp film thickness increases towards discharge end as pinching occurs in flow direction. At the discharge end, the pulp film is divided into two streams by a splitter: low terminal velocity particle rich stream in the upper flow and high terminal velocity particle rich stream in the lower flow. In order to improve the separation efficiency, closely sized and de-slimed ore is fed. Depending on the operating variables and the characteristics of the ore, more than one concentrate streams, or one concentrate together with middling can be obtained by using more than one splitter. (Siyahhan and Ergun, 1999; Ergun and Ersayin, 2002; Yurtsever, 2016). The parameters effective on pinched sluicing are as follows: (Burt, R. O., 1984. Gravity Concentration Technology. New York: Elsevier Science Publishing Company):

• Pulp density,

• Preparation of the material,

• Particle size limits and the required density difference,

• Sluice dimensions,

• Splitter position.

Gravity methods are applied in industrial scale in concentration of ores liberating from a few microns to approximately 30 cm depending on the economic value thereof.

The efficiency of concentration processes decreases as the liberation size decreases. Decrease of efficiency means an increase in the concentration cost and rejection of valuable mineral/minerals together with gangue minerals at certain amounts in the tailing.

In pinched sluice machines, particle settling velocity decreases during gravity concentration as the liberation size decreases. Efficient stratification cannot occur at finer sizes as valuable and gangue minerals settle down with closer settling velocities, and therefore, reasonable rate of valuable mineral is lost in the tailing stream.

In Turkey, low plant recovery has been encountered especially in the beneficiation of chromite ores, and therefore the loss of chromite in tailings. The application of concentration methods besides gravity processes is not economically feasible for most chromite ores. Gravity concentration methods, on the other hand, are not sufficiently successful in the concentration of finely sized ores due to the decrease in the terminal velocity at finer sizes. Today’s technology makes the beneficiation of chromite ores down to 5% chromite grade although grade of fine tailings of several processing plants is as high as 25%. In Turkey, tens of million tons of tailings containing such high amounts of chromite are accumulated near chromite concentration plants.

As a result, all the abovementioned problems have made it necessary to make an innovation in the related technical field. BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a new pinched sluice machine in which concentration process is held by utilizing gravity force, to eliminate the abovementioned disadvantages and to bring new advantages to the related technical field.

The main object of the present invention is to make modifications on the pinched sluice machine in order to obtain higher efficiency than the current situation of gravity concentration. In this way, it is expected that the problem arising from the closer settling velocities of valuable and gangue minerals at finer sizes is eliminated.

The present invention relates to an inclined pinched sluice which is suitable for usage in the beneficiation of low grade ores by gravity methods and which has an inlet through which the pulp is fed and an outlet where the samples are collected. Accordingly, the invention is characterized by comprising the below mentioned elements:

• a magnetic plate which eliminates the problem arising from the closer terminal velocities of finely sized valuable and gangue minerals in pulp medium due to low density difference in said pinched sluice, and positioned at the lower or upper vicinity of a sluice,

• and at least one vibration motor which provides movement of particles in a more freely manner in a pinched sluice in the fluid medium and which is provided at the lower, orthogonal or upper vicinity of a sluice.

In a possible embodiment of the present invention, said sluice inclination is at a value between 6 ^e and 24 ^e .

In a possible embodiment of the present invention, the sluice inclination is at a value between 14 ^e and 19 ^e .

In a possible embodiment of the present invention, said magnetic plate is produced from rare earth magnets (REM) and can generate magnetic field at a value between 100 and 1000 Gauss on the sluice surface.

In a possible embodiment of the present invention, the inclination of the magnetic plate is equivalent to the sluice inclination and is at a value between 6 ^e and 24 ^e . In a possible embodiment of the present invention, the inclination of the magnetic plate is equivalent to the sluice inclination and is at a value between 14 ^e and 19 ^e .

In a possible embodiment of the present invention, said vibration motor has frequency value between 50 and 100 Hz.

In a possible embodiment of the present invention, the vibration motor produces vibration which has amplitude between 50 mhi and 1000 mhi.

In a possible embodiment of the present invention, the vibration motor is positioned at inclinations between 90 ^e and 105 ^e in a manner making reverse angle with respect to the sluice.

BRIEF DESCRIPTION OF THE FIGURES

In Figure 1 , a top representative view of the pinched sluice used in the present art is given.

In Figure 2, a lateral representative view of the subject matter pinched sluice is given.

In Figure 3, a top representative view of the subject matter pinched sluice is given.

REFERENCE NUMBERS

1 Pinched sluice machine

10 Inlet part

11 Sluice

12 Magnetic plate

13 Vibration motor

14 Outlet part

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject matter relates to a new pinched sluice machine (1) where the problem arising from closer terminal velocities of finely sized valuable and gangue minerals in pulp medium due to low density difference is eliminated, and which provides high efficiency in the concentration of low grade ores, and is explained with references to examples without forming any restrictive effect only in order to make the subject more understandable.

In the present invention, “pinched sluice machine” describes probably the oldest gravity concentration equipment used in ore beneficiation, which is designed in different forms and is used for separation of heavy minerals for centuries.

In the invention, “the present pinched sluice machine” refers pinched sluice machines designed in a way that is frequently used in the current technique, which is not the subject of the invention.

In the invention, “modified pinched sluice machine” refers to pinched sluice machines that contain the inventive modifications and elements.

In the invention, “pulp” is the name given to solid-liquid mixtures prepared from the ore which includes valuable minerals in the field of metallurgy.

The representative view of the present pinched sluice (1), where gravity concentration processes are applied, is given in Figure 1. The pinched sluice (1) shown representatively here is formed by an inclined sluice (11) which pinches in the flow direction. The pulp feeding is applied through the inlet part (10) which is the feeding part of pinched sluice distributing over the whole surface at equal heights. Since the sluice (11) pinches towards the outlet part (14), this flow of the pulp takes place on the sluice (11) surface by means of gravity depending on the inclination. Because of the nature of the flow, the fine heavy particles accumulate at the lower parts of the flowing pulp thickness at the outlet part (14) of the sluice (11). Meanwhile, the light particles accumulate at the upper part of the layer. The operation principle of the pinched sluice (1) is explained by the thickening of pulp film layer as a result of pinching (11), and therefore by the formation of hindered settling conditions and consolidation trickling conditions. As a result, heavy and light minerals can be separated by means of splitter or slot placed at a suitable place at the outlet part (14) of the sluice (11).

In Figure 2, the representative view of the modified pinched sluice (1), which is the subject of the invention, is given. Said pinched sluice (11 ) comprises a sluice (11 ) where the separation processes are realized and which pinches from the inlet part (10) towards the outlet part (14) and whose representative view is given in Figure 3. Said sluice (11) is positioned in an inclined manner at specific angles in the pinched sluice machine (1). Flere, said sluice (11) inclination is at a value between 6 ^e and 24 ^e . Preferably, the sluice (11) inclination is between 14 ^e and 19 ^e .

Unlike the currently available pinched sluices as shown in Figure 1 , the modified pinched sluice (1), the subject matter invention, contains at least one magnetic plate (12). Said magnetic plate (12) provides magnetic field for eliminating the problem arising from closer terminal velocities of finely sized valuable and gangue minerals in pulp medium due to low density difference in the pinched sluice (1). As shown in Figure 2, the magnetic plate (12) is preferably positioned at the underneath vicinity of the sluice (11). The magnetic plate (12) is located preferably at the same inclination degrees as the sluice has (11) (if necessary, the magnetic plate is diverged from the sluice at the feeding side and is approached to the sluice surface towards the discharge end such that there is a difference of 1 ^e -2 ^e at most). If preferred, the magnetic plate can be positioned at the upper vicinity of the sluice (11). Said magnetic plate (12) can be produced in various dimensions, and the scope of protection of the invention is not limited to the dimensions and the shape of the magnetic plate (12). In the invention, the magnetic plate (12) can be produced from REM magnets (Rare Earth Magnets). A magnetic field between 100 and 1000 Gauss can be created on the pinched sluice machine by means of the magnetic plate (12).

The distance of the magnetic plate (12) to the sluice surface (11) can be adjusted. The important thing in the invention is that the magnetic plate (12) can transfer the magnetic field to the sluice surface (11) which is necessary for the pinched sluice (1)to work with high efficiency.

In the related technical field, the hindered settling conditions adversely affect the stratification as the feed particle size decreases as a result of the increased pulp viscosity in the pinched sluice (11). In order to minimize this unfavorable condition, the pinched sluice (11), which is the subject of the invention, is subjected to vibration at specific frequencies. By means this, the particles move in a more freely manner in the fluid medium in the pinched sluice (11). Flere, as shown in Figure 2, a vibration motor (13) is added to the pinched sluice machine (11) as a vibration provider. Said vibration motor (13) can create vibrations having amplitude between 50 mhi and 1000 mhi and a frequency between 10 and 100 Flz for the pinched sluice machine. The vibration motor (13) used in the invention has power of 0.25 kW.

In the invention, the vibration motor (13) can be positioned at the underneath vicinity of the sluice (11). If preferred, the vibration motor (13) can also be positioned above the sluice (11). The vibration motor can be positioned at the feeding side of the sluice, at the product discharge side or at any point in between in a manner providing vibration which is perpendicular to the flow or which is inclined or which is parallel to the flow. The vibration motor (13) can be positioned at similar inclinations as the sluice has (11). If preferred, the vibration motor (13) can be positioned in a perpendicular manner (90 ^e ) to the sluice (11). If preferred, the vibration motor (13) can be positioned at inclinations such that a different angle can be adjusted with respect to the sluice (11), in other words, said inclination angle can be at any value between 30 ^e and 150 ^e . The important thing in the present invention is that the vibration motor (13) is able to provide the vibration necessary to ensure high operation efficiency of the pinched sluice machine (1 ).

The modified pinched sluice (1) designed in the invention can be scalable in accordance with the size of the processing and production plants where it is used, and the dimensions of the pinched sluice machine (1) does not limit the protection scope of the invention. The innovative characteristic of the modified pinched sluice (1), which is the subject matter of the invention, over the currently available pinched sluices is the presence of magnetic field and vibration to provide technical solution to the problems and disadvantages frequently encountered in the concentration processes in sluice (11).

The modified pinched sluice (1), the subject matter invention, eliminates the problem arising from closer terminal velocities of finely sized valuable and gangue minerals in pulp medium due to low density difference and increases the process efficiency of concentration.

The modified pinched sluice (1), the subject matter invention, is suitable for concentration processes in industrial scales and its dimensions can be adjusted according to the capacity of the processing plant. The modified pinched sluice (1) increases the concentration efficiency to high levels, and thus decreases valuable mineral losses into tailings. By means of this, it allows the production facility to make higher profits. Moreover, it is ensured that the underground resources of the country are utilized at the highest level.

The modified pinched sluice (1), the subject matter invention, is expected to find wide application in the mining industry due to its advantages such as low energy consumption, high capacity and low initial investment cost, as well as its potential to enable the use of ores and plant tailings that are difficult to concentrate with sufficient recovery.

The protection scope of the present invention is set forth in the annexed claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.