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EP-3641941-B1 - AN INTEGRATED SEPARATOR SYSTEM & PROCESS FOR PRECONCENTRATION AND PRETREATMENT OF A MATERIAL

EP3641941B1EP 3641941 B1EP3641941 B1EP 3641941B1EP-3641941-B1

Inventors

  • SHI, FENGNIAN
  • MANLAPIG, EMMANUEL

Dates

Publication Date
20260513
Application Date
20180621

Claims (10)

  1. An integrated separator system for the preconcentration of a material, the system comprising a grizzly screen having a plurality of grizzly bars (101, 102, 202), the grizzly screen allowing disintegrated particles of the material to pass through the grizzly screen whilst non-disintegrated particles are retained on top of the grizzly screen; characterised in that : the grizzly bars (101, 102, 202) act as electrodes (101, 102, 202) which provide a high voltage pulse (HVP) discharge to the material; the high voltage pulse (HVP) discharge is applied at a voltage and energy sufficient to disintegrate particles of the material containing high conductivity/permittivity minerals; and particles that do not contain high conductivity/permittivity minerals are protected by those containing high conductivity/permittivity minerals and are not broken.
  2. The separator system of claim 1 wherein the grizzly screen comprises grizzly bars (101, 102) which act as alternating positive (101) and negative electrodes (102) of a screen element.
  3. The separator system of claim 1, wherein the grizzly screen acts as a negative electrode (202) and a positive electrode (201) is located above the grizzly screen.
  4. The separator system of claim 1 , wherein the grizzly bars (101, 102, 202) are cylindrical or rectangular in cross-sectional shape.
  5. The separator system of any one of the preceding claims, wherein the gap between the grizzly bars (101, 102, 202) is set between 10 to 200mm, and wherein the grizzly bars are substantially parallel to each other.
  6. The separator system of claim 1, wherein: (i) the grizzly bars (101, 102, 202) are rectangular in cross sectional shape and are substantially parallel to each other; or (ii) the grizzly bars (101, 102, 202) are rectangular in cross sectional shape and are arranged in a cone shape with a first end of the grizzly bars having a larger gap therebetween than compared to a second end of the respective grizzly bars.
  7. A process for preconcentration of a material preferably a mineral within a rock which comprises: a) providing the material into an integrated separator system comprising a grizzly screen having a plurality of grizzly bars (101, 102, 202) acting as electrodes (101, 102, 202) which are capable of providing at least one high voltage pulse discharge(s) to the material; b) applying one or more high voltage pulse discharge(s) to the material as the material is travelling along the grizzly bar(s) (101, 102, 202) to preferentially disintegrate the particles containing mineral grains of high conductivity/permittivity while particles that do not contain high conductivity/permittivity minerals are protected by those containing high conductivity/permittivity minerals and are not broken; c) separating the disintegrated particles from unbroken particles by way of the grizzly screen having a plurality of grizzly bars (101, 102, 202), resulting in the separation of the feed material into low grade (oversize) and high grade (undersize) products; and wherein the disintegrated particles from step b) pass through a screening element for further treatment.
  8. A process according to claim 7, wherein undersized ore material is subjected to a subsequent stage of high voltage pulse treatment to further increase a waste reject rate; and/or wherein Run of Mine ore is presented to the integrated high voltage pulse and grizzly screen, for multiple stage treatments without a pre-screening requirement.
  9. A process according to claim 7 or claim 8, wherein:- (i) the process is applied to ore feed particles larger than or equal to 50 mm; or (ii) wherein the grizzly screen comprises grizzly bars (101, 102, 202) which act as alternating positive (101) and negative (102) electrodes in said screen element, and the process is applied to ore feed particles smaller than 50 mm.
  10. The process according to any one of claims 7 to 9, wherein the process is used to remove sulphide minerals such as pyrite or other mineral matters having higher conductivity/permittivity than coal to improve coal quality and to reduce environmental impact.

Description

FIELD OF THE INVENTION The present invention provides an integrated separator system for the preconcentration of a material. In particular, the invention relates to an integrated separator system comprising one or more electrodes used for the preconcentration of a material contained within a host rock. The present invention also provides a process for preconcentration of a material. The integrated separator system and process of the present invention finds particular application for preconcentration where the material is a mineral in an ore being processed by the mining industry. Specific reference will be made to this application hereafter. However, it should be understood by the skilled person that the invention may find broader application. BACKGROUND Over the past decades, many technical improvements have been implemented to improve Run of Mine processing and sorting. The first approaches, now almost a century ago, such as shown in US1947035A, consisted in complex mechanical devices using a variety of grizzly screens and conveyer belts to remove unworkable rocks and tree roots from valuable minerals. While this device enabled improved gold recovery from other Run of Mine mineral, the intricacy of the mechanical parts involved implies a high maintenance which eventually reduces the profitability of mining operations. Another approach, shown in US 3460766A, uses an electrical current instead of shear mechanical forces to break even the hardest material. The principle relies on exploiting the different conductivity channels within a rock. Once subjected to either an AC or DC current or voltage, a local increase of temperature is induced thereby resulting in thermal stress. The higher the current or voltage, the higher is the produced thermal stress eventually enabling the rock breakage. In the aforementioned example, this principle is used to process Run of Mine, breaking larger rocks into smaller ones which can be subsequently processed at a lower cost. However, this method does not allow sorting smaller rock fragments as a function of their mineral content. Similar examples, such as the ones shown in JP H09 192526A and WO 99/03588, have used a comparable approach of breaking larger rocks into smaller fragments using high voltage electrical pulsed power, developing this technology further to enable continuous feedthrough with higher efficiency, thus enabling higher throughput but without any sorting functionality of the rock fragments as a function of their mineral content. Uri Andres ("Liberation study of apatite-nepheline ore comminuted by penetrating electrical charges." Int. J. of Min. Proc. (1977) 4, 33-38) demonstrated that high voltage pulse disintegration results in superior liberation of mineral grains as compared with conventional grinding techniques. Despite mounting laboratory-scale evidence of the efficacy of high voltage pulse disintegration for mineral liberation, development of the technology for a full-scale operation has stalled, primarily because the energy required to achieve desirable mineral liberation is approximately two to three times that of mechanical comminution, amounting to approximately 90 kWh/t for typical mineral ores (Andres, U. et al. "Energy consumption and liberation of minerals in explosive electrical breakdown of ores." Trans. of the Inst. of Min. and Metall., (2002) 110, 149-157). However, Zuo, W. et al. ("Pre-concentration of copper ores by high voltage pulses. Part 1: Principle and major findings." Min. Eng. (2015) 79, 306-314) demonstrated recently in laboratory scale batch tests the selective breakage of mineralised particles from barren rocks ones owning to the application of relatively low levels of pulse energy to, followed by size-based screening separation. More recent technological developments enable the feed ore to be split into high-grade and low-grade products, using only a fraction of the energy typically required to break all rocks in a Run of Mine. Nevertheless, using the technology of high voltage pulse selective breakage in continuous operation and the subsequent size-based screening required for sorting mineral rich rock fragments from barren ones is still an obstacle for industrial uptake of the low levels of pulse energy technology, consequently requiring further technological development. SUMMARY OF THE INVENTION According to the present invention, there is provided an integrated separator system for the preconcentration of a material as defined by claim 1. The grizzly bars may be arranged in the screen element such that there are alternating positive and negative electrodes which provide the HVP discharge to the material. The grizzly bars may also be arranged in the screen element wherein the grizzly bars/ screen element form a negative electrode and the system further comprises a positive electrode located above the grizzly screen element. According to the present invention, there is also provided a process for preconcentration of a material