PRIORITY DOCUMENT

[0001 ] The present application claims priority from Australian Provisional Patent Application No. 2021904231 titled “APPARATUS AND PROCESS FOR PROCESSING MATERIALS” and filed on 23 December 2021, the content of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates generally to processing of materials to alter one or more physical or chemical properties of the materials. In a particular form, the present disclosure relates to apparatus and processes for fine grinding, agglomerating or dissociating chemical feedstock materials such as ores, inorganic substances or organic substances.

BACKGROUND

[0003] The waste from conventional precious metal extraction processes is commonly known as tailings. The characteristics of tailings can vary greatly and are dependent on the ore mineralogy together with the physical and chemical processes used to extract the product from the ore.

[0004] Tailings are either processed in a tailings processing facility and disposed of, or further processed to extract other valuable minerals. The processing of native ore and tailings requires the use of various chemical reagents to leach and/or separate the precious metals from the ore and/or tailings. Tailings dams and/or stockpiles are a significant waste problem from mine operations.

[0005] Many tailings from precious metal extraction processes contain precious metal nanoparticles that are not recovered by the conventional precious metal extraction processes used. One reason why precious metal nanoparticles are overlooked in the mining industry is because the industry still relies for the most part on the traditional fire assay to determine the content of precious metals in the ore or tailings. However, precious metal nanoparticles may not reveal themselves in a regular fire assay without prior processing because they may be strongly attached to their various hosts, thereby prohibiting agglomeration, and/or absorption into the positively charged crucible that is used in the fire assay industry, which is typically made from magnesium dioxide. Furthermore, analytical results are sometimes referred to as ‘phantom’, ‘white’ and ‘elusive’ because some analytical methods reveal precious metals where other methods fail or because the results are inconsistent.

[0006] Presently, the production and use of precious metal nanoparticles from tailings are generally not considered feasible in the mining industry. However, precious metals at lower grades are becoming increasingly attractive for resource companies despite the greater challenge in the recovery of these metals into saleable products.

[0007] Most efforts to date to recover precious metal nanoparticles from tailings or other materials have been at a laboratory scale and no significant volumes of precious metals have been extracted. Furthermore, a coherent extraction strategy for precious metal nanoparticles has not been developed.

[0008] Despite the lack of progress in the mining industry, precious metal nanoparticles have attracted substantial interest in many fields because of their unique physical, chemical, and surface properties, such as:

• size and shape-dependent strong optical extinction and scattering which is tuneable from ultraviolet (UV) wavelengths all the way to near infrared (NIR) wavelengths;

• large surface areas for conjugation to functional ligands; and

• little or no long-term toxicity or other adverse effects in vivo allowing them to be used in living systems.

[0009] Precious metal nanoparticles are now being widely investigated for their potential use in a wide variety of biological and medical applications as imaging contrast agents, therapeutic agents, biological sensors, cell-targeting vectors, and manufacture of nano gold particles on silver using mutant microbes. For example, a discovery employed in the medical research industry for the last 15 years is the application of negative gold nanoparticles. These gold nanoparticles are small crystals of gold that, because of quantum effects, have a very strong negative overall charge. Gold nanoparticles are an example of a conductive electret which in classical chemistry and physics would be considered impossible, but this phenomenon has been taken advantage of in a wide variety of applications in the medical sector. The way the crystals are prepared influences their final size and their overall charge.

Without being bound by any theory of operation, they appear to be a case of a standing wave set up in the electron cloud driven by a resonance in the weak force. There are many possible explanations for this phenomenon in quantum mechanics, but the net effect is that a given crystal of pure gold or other metal can hold far more electrons than classical physics or chemistry would presuppose giving the crystal a strong net negative charge. These crystals are composed of a particular number of atoms which can vary across a wide range but are typically in the order of 140 to 180 atoms. The particular number is generally referred to as a “magic” number in the relevant literature.

[0010] There is thus a need for apparatus and processes that can be used to efficiently recover precious metal nanoparticles from mining tailings or other crude materials containing them. Alternatively, or in addition, there is a need for apparatus and processes for recovering precious metal nanoparticles from mining tailings or other crude materials containing them that provide an alternative to existing apparatus and processes.

SUMMARY

[0011] According to a first aspect, there is provided an apparatus for altering one or more physical or chemical properties of a material, the apparatus comprising: first and second grinding surfaces movable relative to one another, the first and second grinding surfaces being spaced apart by a distance whereby said distance is such that shear forces are applied to a fluid containing the material entrained between the grinding surfaces when the first and second grinding surfaces move relative to one another; and first and second electrodes configured to apply an electric charge to the fluid containing the material entrained between the grinding surfaces.

[0012] The apparatus can be used for fine grinding, agglomeration or dissociation of the material.

[0013] According to a second aspect, there is provided a process for altering one or more physical or chemical properties of a material, the process comprising: placing a fluid containing the material between first and second grinding surfaces that are movable relative to one another and moving the first and second grinding surfaces relative to one another to apply shear forces to the fluid containing the material entrained between the grinding surfaces; and applying an electric charge to the fluid containing the material entrained between the grinding surfaces.

[0014] The process can be used for fine grinding, agglomeration or dissociation of the material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Embodiments of the present disclosure will be discussed with reference to the accompanying drawings wherein:

[0016] Figure 1 is a top view of an embodiment of part of an apparatus disclosed herein;

[0017] Figure 2 is a partial cross section view through A of the embodiment of the apparatus shown in Figure 1;

[0018] Figure 3 is a schematic close up of the embodiment of the apparatus shown in Figure 1;

[0019] Figure 4 is a perspective view of another embodiment of an apparatus disclosed herein; [0020] Figure 5 is an exploded view of the embodiment of the apparatus shown in Figure 4;

[0021] Figure 6 is a side view of the embodiment of the apparatus shown in Figure 4; and

[0022] Figure 7 is a cross section view through A-A of the embodiment of the apparatus shown in

Figures 4 and 6.

[0023] In the following description, like reference characters designate like or corresponding parts throughout the figures.

DESCRIPTION OF EMBODIMENTS

[0024] As used herein, the term “precious metals” denotes any metallic element of high economic value and typically denotes rare, naturally occurring metallic chemical elements. Precious metals typically include, for example, one or more metal selected from the group consisting of gold, silver, platinum, palladium, ruthenium, rhenium, rhodium, osmium, iridium, copper, zinc, and mixtures thereof. The term “nanoparticle(s)” denotes a particle having a size less than 500 nm, preferably from about 1 to about 500 nm, or from about 10 to about 400 nm, or from about 20 to about 300 nm, or less than about 100 nm, or any range or value therebetween.

[0025] The apparatus and processes disclosed herein have resulted from the inventors’ surprising finding that entrained materials can be processed to produce precious metals on a nanoscale that are agglomerated. By using the apparatus and processes disclosed herein, entrained materials can be agglomerated such that the residual charge is substantially dissipated, and the agglomerated material takes the form of spheres or as “sausages” made from an agglomeration of microscopic spheres. These are then readily separated from the remaining material, and optionally converted to precious metals and purified.

[0026] Referring now to Figures 1 to 7, there is shown embodiments of an apparatus 10 for altering one or more physical or chemical properties of a material 12. The apparatus 10 comprises a first grinding surface 14 and second grinding surface 16. The grinding surfaces 14 and 16 are movable relative to one another. The first grinding surface 14 and second grinding surface 16 are spaced apart by a distance D whereby said distance is such that shear forces are applied to a fluid 18 containing the material 12 entrained between the grinding surfaces 14 and 16 they move relative to one another.

[0027] The apparatus 10 also comprises a first electrode 20 and a second electrode 22. The first electrode 20 and the second electrode 22 are configured to apply an electric charge to the fluid 18 containing the material 12 entrained between the grinding surfaces 14 and 16. [0028] Advantageously, the apparatus 10 can be used to alter one or more physical or chemical properties of the material 12 at low to moderate temperatures and pressures. This is done using a combination of electromechanical induced shearing and electrically induced changes. For example, the apparatus 10 can be used to fine grind a material 12. Alternatively, or in addition, the apparatus 10 can be used to cause a material 12 to agglomerate. Alternatively, or in addition, the apparatus 10 can be used to cause a material 12 to dissociate.

[0029] In certain embodiments, the apparatus 10 is used for extraction of precious metals from materials 12 containing them. In these embodiments, the apparatus 10 may be configured to pulverise the materials 12 that contain precious metals that are either detectable or not detectable. Any material 12 may be treated in accordance with these embodiments, including raw ore, tailings from ore processing units, coal, shale or the like and other materials 12 (such as waste products) that may contain one or more precious metals. In these applications, the apparatus 10 may significantly reduce the energy required for comminution of an ore. A benefit of the apparatus 10 and process described herein over traditional crushing is that there is no media used in the apparatus 10 or the process. In a conventional mining process, between 1/3 and 1/2 of the material 12 in a typical ball mill is composed of grinding media which consumes half or more than half of the energy in the mill. Because the conventional process is so energy intensive and consequently expensive, mine managers are frequently inhibited in their quest for fine grinding to achieve high yields because the typical results don’t outweigh the increased costs.

[0030] In certain other embodiments, the apparatus 10 is used to agglomerate fine particles of precious metals from materials 12. For example, this allows for the extraction of precious metal nanoparticles from materials 12 at low temperatures utilising electrically assisted tensile failure mechanisms. In the “electromechanical” process, it is not suggested that a chemical reaction takes place, but rather denotes a process in which materials 12 may be brought together to bring about a change in one or more of the materials 12, regardless of whether a reaction takes place, denoting a device in which materials 12 may be processed by comminution.

[0031] Testing by the applicant has found that the apparatus 10 and process can be used to produce precious metals in amounts significantly greater than conventional extraction techniques, including from native ore or from material 12 that has very little or no detectable precious metals using conventional analytic techniques (tailings). Thus, the apparatus 10 and process can recover precious metals in an amount far greater than conventional precious metal mining processes. For example, the average concentration of gold is about 0.005 parts per million (ppm) in the earth’s crust, and the concentration in ore that is processed for mining is about 1 ppm to 5 ppm. Test results show that the apparatus 10 and process described herein can process ore such that the raw processed ore increases by a factor of 4-5 over the base assay. Specifically, mining tailings that contain anywhere from about 0.01 ppm to about 1.0 ppm precious metals (as measured by the ICP and Fire Assay tests) can be processed using the apparatus 10 and process described herein to contain anywhere from about 3 to about 40 ppm.

[0032] The processed material may contain at least one or more precious metal nanoparticles. The processed material from the apparatus 10 and process described herein that contains the precious metal nanoparticles can be transported to one or more concentration/conversion units, to separate the precious metal nanoparticles from the processed material according to their charge value. The concentration/conversion unit(s) can be a stationary or movable electrically charged plate - also known as a “wave table”. The subsequently processed precious metal nanoparticles then can either be stored for use in a variety of materials (medical devices, batteries, etc.). Alternatively, or in addition, the concentrated/separated precious metal nanoparticles can be transported to an optional purification unit for production of pure or substantially pure precious metal using purification techniques that are known in the art.

[0033] In certain other embodiments, the apparatus 10 is used to treat or disassociate pigments or pharmaceuticals and the like. An example is in the treatment of per- and polyfluoroalkyl contaminated materials (PFAS) where the PFAS is broken down in the apparatus 10 with the addition of a catalyst (calcium carbonate). The Applicant has found that PFAS is reduced below reportable limits by this process with calcium fluoride as the by-product.

[0034] In certain other embodiments, the apparatus 10 is used to recover precious metals from electronic and electrical waste products. Advantageously, the apparatus 10 is not affected by extraneous deleterious materials 12, as in other e-waste processing systems which are invariably rendered inoperable by cross contamination.

[0035] The material 12 to be treated can be any inorganic or organic material, whether pure or as a mixture with other materials 12. In some applications, the material 12 is a precious metal containing material 12, such as an ore or mining tailings. The precious metal may be gold or silver, platinum group metals (PGMs), and other valuable base and rare metals such as nickel, cobalt, copper, rare earth elements (REE) including yttrium and scandium, as well as uranium, thorium, manganese, zinc, cadmium, molybdenum, vanadium, titanium and other minor elements such as vanadium, germanium and gallium.

[0036] The material to be treated may be a single substance or a mixture of two or more substances.

[0037] The fluid 18 containing the material 12 may be in the form of a solution, a slurry, an emulsion, a dispersion, a suspension or the like. [0038] The material 12 may itself be a fluid in which case it may be used as is without further modification. In that case, the term “a fluid containing the material” as used herein means the fluid material itself. Alternatively, the material 12 may be a solid, liquid, mixture or suspension that is combined with a carrier fluid for treatment in the apparatus 10. The solid, liquid, mixture or suspension is combined with a carrier fluid to form a fluid 18 containing the material 12.

[0039] The carrier fluid may be an inert material or a reactive material. The carrier fluid is an electrically conductive liquid. Suitable conductive liquids include water, salt water, sea water, aqueous solutions, ionic fluids, mineral acids such as sulfuric acid, liquid mercury, liquid gallium, liquid gallium aluminium alloy, liquid sodium potassium alloy, etc.

[0040] Where necessary, one or more additives may be added to the fluid 18. For example, an electrolyte may be added to the fluid. The electrolyte may be acidic or alkaline. The electrolyte may be a hydroxide such as sodium hydroxide. Advantageously, a hydroxide may be added to enhance current flow through the fluid.

[0041] In the embodiment illustrated in Figures 1 to 3, the first grinding surface 14 is formed on shear plates 24 and the second grinding surface 16 is formed on an inner surface 26 of outer housing 28.

[0042] In the embodiment illustrated in Figures 4 to 7, the first grinding surface 14 and the second grinding surface 16 are formed on discs 60/60a and 62, respectively. As best seen in Figure 5, in the illustrated embodiment there are effectively two first grinding surfaces 14, with one on each disc 60 and 60a, and two second grinding surfaces with one on each side of central disc 62. The discs 60, 60a and 62 can be formed from any suitable material, such as structural steel. One suitable material is BISALLOY® 70. The discs 60 and 60a are 50mm in thickness and the disc 62 is 100mm in thickness.

[0043] The grinding surfaces 14 and 16 are formed from a high wear resistant material. A range of wear resistant materials can be used. Suitable wear resistant materials include, but are not limited to, silicon carbide, nickel aluminide (i.e. NLA1 - Alloy optionally hardened by TiC, Z1O2, WC, SiC or graphene), and tungsten carbide. The wear resistant material could also be formed using a suitable case hardening (i.e. surface treatment) process such as carburizing, nitriding, boronizing, titanium-carbon hardening, titanium-nitride hardening, flame hardening, induction hardening or laser hardening.

[0044] In certain embodiments, each grinding surface 14 and 16 is formed from a silicon carbide material. Silicon carbide is exceedingly hard, synthetically produced crystalline compound of silicon and carbon. Its chemical formula is SiC. Silicon carbide has a Mohs hardness rating of 9, approaching that of diamond. In addition to hardness, silicon carbide crystals have fracture characteristics that make them extremely useful in grinding. Optionally, the silicon carbide material may be reinforced, such as with carbon fibres. The grinding surfaces 14 and 16 can be formed using microwave vacuum furnace (MVF) technology or chemical vapour infiltration (CVI) technology.

[0045] It will be appreciated that in each of the illustrated embodiments the grinding surfaces 14 and 16 are movable relative to one another. In the embodiment illustrated in Figures 1 to 3, the shear plates 24 containing the first grinding surfaces 14 rotate relative to the second grinding surface 16. In the embodiment illustrated in Figures 4 to 7, the first grinding surface 14 and the second grinding surface 16 rotate relative to one another. More specifically, the second grinding surfaces on disc 62 rotates whilst the first grinding surfaces 14 on discs 60 and 60a are held stationary.

[0046] The first grinding surface 14 and second grinding surface 16 are spaced apart by a distance D and the fluid 18 containing the material 12 is introduced into the gap between the first grinding surface 14 and second grinding surface 16. As a result, shear forces are applied to a fluid 18 containing the material 12 entrained between the grinding surfaces 14 and 16 and they move relative to one another. The distance D can be adjusted as required. The distance D will typically be determined and set based on the particle size of the material 12. By way of example only, the distance D may be from about 10 micron to about 2mm. For example, most tailings have an average particle size of 75 micron and consequently, the distance D would be set at about 75 micron. In other embodiments, a typical distance D between the first grinding surface 14 and second grinding surface 16 is in the order of 1mm to 2mm, though it has been found in certain circumstances that a wider distance D up to 30 millimetres has been found to be efficacious. This depends entirely on the incoming material size and what function that the apparatus is intended to perform on the material.

[0047] Without being bound by theory, it has been found that most if not all stone and other ionically bonded material has a tensile strength that is in the region of 10% of that of the compressive strength .It has also been found that when an ionically bonded material is subjected to tension as well as an appropriate voltage, amperage and wave form that the energy required to fracture the material is approximately 10% of the tensile energy. This means that electrically assisted tensile failure requires only a theoretical 1 % of the energy to that of compressive failure.

[0048] If granular material enters the region between the grinding surfaces 14 and 16 and the stationary plates the boundary layer on the surface of the plates is such that even if the particle is smaller than the gap the particle is subjected to considerable tension because of the relative differences in the motion of the two plates. If there is voltage, typically in the region of 25 volts but in some cases as high as 500 volts and for other applications as low as 2 volts then the energy required for comminution has been found to be as low as 5% of that required for compressive failure. [0049] Advantageously, no media used. In a conventional grinder, between 1/3 and 1/2 of the material in a typical ball mill is composed of grinding media which consumes half or more than half of the energy in the mill. The mill itself is also consumed by the media used in the grinding process as well as the target material. The action of the media on itself and of the media on the ball mill casing is usually more than that on the material being processed. Because the conventional process is so energy intensive and consequently so expensive, mine managers are frequently inhibited in their quest for fine grinding to achieve high gold yields, because the typical results don’t outweigh the increased costs.

[0050] In certain embodiments, a plurality of apparatus 10 may be used in a series with each apparatus having a progressively small distance D. This allows material 12 with a larger particle size to be progressively comminuted which may then prolong use of each apparatus 10 by better managing wear in each apparatus. This also potentially allows a higher throughput.

[0051] The first electrode 20 and the second electrode 22 are adapted to be held at respective first and second predetermined voltage potentials. The first electrode 20 and the second electrode 22 are each positioned on or in the apparatus 10 to allow a current to pass through at least one region between the first grinding surface 14 and second grinding surface 16 containing the fluid 18 containing the material 12 to be treated.

[0052] In the embodiment illustrated in Figures 1 to 3, the outer housing 28 comprises the first electrode 20 and the inner housing 32 comprises the second electrode 22.

[0053] In the embodiment illustrated in Figures 4 to 7, the discs 60/60a comprise the first electrode 20 and disc 62 comprises the second electrode 22. The discs 60/60a are insulated electrically from the frame and the disc 62 and have a voltage is applied between the stationary discs 60/60a and the rotating disc 62.

[0054] An electric charge is applied to the fluid 18 containing the material 12 entrained between the grinding surfaces 14 and 16 using any source of direct current or alternating current. The introduction of a variable voltage with amperage, frequency and waveform imposed to the electromechanical process, can be varied to improve the yield of processed materials recovered. The current may be selected to have a desirable voltage, frequency and/or waveform. The applied current may be from about 20 Amps to about 100 Amps, such as about 20 Amps to about 40 Amps or 40 Amps to about 60 Amps. In certain embodiments, the current applied is from about 50 Amps to about 65 Amps. The voltage may be about IV to about 50V. The frequency may be up to about 50 MHz. The current may be of any waveform such as, for example, a square or sinusoidal waveform. The operation can be monitored by a PLC or other suitable monitoring equipment which measures the changes in amperage due to the proximity of the respective grinding surfaces 14 and 16 to achieve the optimum results. Specifically, the stationary disc 60 has its gap to the rotating disc 62 monitored by the PLC on the basis of a change in amperage which is due to a change in the gap between the stationary disc 60 and the rotating disc 62. The PLC controls the hydraulic pressure to the hydraulic rams which suspend disc 60 relative to disc 62. In some cases, the hydraulic rams carry the weight of disc 60 and balance the gap. On start-up, the discs 60/60a and 62 are moved apart and gradually bought together until the required amperage is achieved. In some cases, the hydrostatic lift due to the pumping action of the fluid and material being processed are enough to force the discs 60/60a and 62 apart and the hydraulic force is automatically changed from lifting upwards, carrying the weight of the assembly to forcing down against the hydrostatic force to achieve the requisite gap between the discs 60/60a and 62.

[0055] The motor and rotating disc 62 are suspended in a similar manner to that of the top stationary disc 60 and has its disposition controlled by the same PLC that controls the top stationary disc 60 with the same objectives in mind. It has been found that if the peripheral speed of the rotating discs 60/60a exceeds 16 meters per second the hydrostatic force driving the discs apart becomes quite significant and the hydraulic rams are required to exert considerable force to achieve the requisite gap between the discs 60/60a and 62.

[0056] Turning to details of the embodiment illustrated in Figures 1 to 3, the apparatus 10 further comprises outer housing 28 and inner housing 32. Both housings 28 and 32 are circular in plan view and they are coaxial with respect to one another. Inner housing 32 is journaled for rotation within outer housing 28 and, in operation, rotates at between about 1800 rpm and about 2400 rpm. A plurality of shear plates 24 extend outwardly from a side wall 34 of inner housing 32. In the illustrated embodiment there are four shear plates 24. The shear plates 24 could extend radially out from the inner housing 32 but in the illustrated embodiment the shear plates 24 extend tangentially out from the side wall 34 of inner housing 32. The shear plates 24 are angled backwards with respect to the direction of rotation of inner housing 32. The shear plates 24 are attached to the inner housing 32 via adjustment pins 44 that can be used to change the angle of the shear plates 24 and hence the distance D between the grinding surfaces 14 and 16. The shear plates 24 each contain the first grinding surface 14.

[0057] An upper surface 36 of the inner housing 32 is angled so that material 12 in fluid 18 that is introduced into the apparatus 10 runs down the angled upper surface 36 and into the gap 38 between the outer housing 28 and inner housing 32 where it is subjected to shear forces applied by grinding surfaces 14 and 16 and also electrical current applied by first electrode 20 and second electrode 22. Treated material 40 is collected via a valve 42 at the bottom of the outer housing 28. Optionally, some or all of the material 40 collected at the valve 42 can be recycled back into the apparatus 10 for further treatment.

[0058] Turning to details of the embodiment illustrated in Figures 4 to 7, the apparatus 10 further comprises a frame 50. Discs 60 and 60a are held in a fixed position within the frame 50 whilst disc 62 is journaled for rotation between discs 60 and 60a and relative to the frame 50. Material 12 in fluid 18 is introduced into the apparatus 10 via central aperture 52 (see Figure 7) after which it fills the gaps between discs 60/60a and disc 62 where it is subjected to shear forces applied by grinding surfaces 14 and 16 and also electrical current applied by the first electrode 20 and second electrode 22. The material 12 in fluid 18 moves radially outwardly under centrifugal force and is collected at the periphery of the discs 60/60a and 62. The gaps between discs 60/60a and disc 62 can be adjusted by moving discs 60/60a upwardly or downwardly with respect to disc 62. A sheath 54 surrounds the discs 60/60a and 62 and contains treated material 40 at the periphery of the discs 60/60a and 62.

[0059] It has been found that when voltage is applied to a material 12, when it is stressed, the energy required to fracture the material 12 is reduced by a significant amount. Typically, with an ionically bonded material 12 like quartz, the energy required to fracture the material 12 in tension is approximately 10% of that required to fracture the same material 12 in compression. With the application of an appropriate voltage at the right instant the energy required to fracture the quartz can be reduced to 10% of the energy required to fracture the quartz in tension. This amounts to a theoretical energy requirement of 1 % of that required in compression.

[0060] By way of example, compression failure is the conventional method for crushing rock, and in a mining, application can account for more than 50% of the total cost of obtaining precious metals from the processed ore. The embodiments described herein are capable of using less than 50%, or less than 20%, or less than 10%, or less than 5%, or more commonly about 3% of the energy that is required to comminute the material 12 using direct crushing by compression.

[0061] In certain embodiments, the apparatus 10 further comprises a feeding system 30 configured to introduce the fluid 18 containing the material 12 at a suitable water to solids ratio to the grinding surfaces 14 and 16. By way of example the water to solids ration may be from about 20% water to about 95% water, such as between about 30% to about 50 % water. The feeding system 30 can be specifically designed or integrated to an industry standard.

[0062] Also disclosed herein is a process for altering one or more physical or chemical properties of a material 12. The process comprises placing a fluid 18 containing the material 12 between first and second grinding surfaces 14 and 16 that are movable relative to one another and moving the first and second grinding surfaces 14 and 16 relative to one another to apply shear forces to the fluid 18 containing the material 12 entrained between the grinding surfaces 14 and 16 and applying an electric charge to the fluid 18 containing the material 12 entrained between the grinding surfaces 14 and 16.

[0063] The processes described herein may be batch processes or continuous processes. [0064] One particular non-limiting application of the apparatus 10 and processes described herein will now be illustrated. In conventional analyses, after precious metal nanoparticles are liberated from their hosts and a sample is being prepared for analysis by inductively coupled plasma (ICP) or the like, the material 12 is dissolved in Aqua Regia (a mixture of nitric acid and hydrochloric acid, optimally at a molar ratio of 1:3), and a small sample of the solution is then inspirated into an ICP machine. This test presupposes that the precious metal, especially gold, or other species dissolves in Aqua Regia.

[0065] The present applicant has found that in the case of the precious metal nanoparticles, the high negativity of the nanoparticles renders them essentially insoluble in the acid. The precious metal nanoparticle crystals typically are in the 100-nanometer size range and, because of Stokes Law, they do not readily sink in water. The conventional analysis of these materials 12, using ICP and the Fire Assay, therefore leads to confusing and inaccurate results.

[0066] If the material 12 in the vessel being tested is left for a longer duration, then some (but not necessarily all) of the nanoparticles may sink to the bottom. This is typically interpreted by the analytical chemist that something in the sample has bound with the precious metal and made it unavailable for inspiration and analysis by precipitating to the bottom of the beaker. This is known in the industry as “Preg Robbing". The precious metal nanoparticles, typically being highly negatively charged, do bind to other species but rather usually exist in the form of macro beads and not individual atomic species.

[0067] The present applicant has discovered that by treating the processed material 40 which contains precious metals, some or all of which are in the form of negatively charged nanoparticles (e.g., finely divided slurry) using the apparatus 10 and processes described herein in a neutral pH solution with a conductivity agent, the material so treated is readily amenable to electrophoretic separation of the negative material from the processed material. For example, caustic soda may be used as a conductivity agent to increase the conductivity of the material 12 and/or the fluid 18.

[0068] Without wishing to be bound by any theory of application or operation, the present applicant has observed that the monoatomic hydrogen produced, when a hydride reducing agent is introduced into a solution containing the processed material 40, sufficiently reduced the charge on the precious metal crystals, such that the “weak atomic force” is sufficient to agglomerate the crystals into a spherical bead. This agglomeration is the result of balancing between three or more forces.

[0069] Because of quantum effects, the crystals have a net overall strong negative charge which tends to repel individual crystals. This repulsion effect is visible in electron microscope photographs of the processed material 40. The hydride appears to scavenge some of this negative charge reducing the repulsion, whereupon the “weak atomic force” becomes the dominant force and allows the crystals to aggregate. [0070] In experiments conducted by the present applicant, different samples from five different mining tailings storage facilities (TSF’s) where examined before and after subjecting them in the apparatus 10. The tailings were the waste product of prior extractions of regular gold (free and/or refractory gold) from ore.

[0071] All tailings used were officially categorized to contain no more or very little regular gold, which was confirmed using the ICP and Fire Assay tests. The results are provided in Table 1. The descriptor “Q Treated” is the concentration (ppm) after processing in the apparatus 10.

[0072] Table 1 - Results from processing of tailings in apparatus 10 [0073] As shown above, subjecting material 12 that previously contained little or no precious metal, when analysed using the conventional ICP and Fire Assay test, to the apparatus 10 and processes described herein resulted in processed finely divided powder material 40 that contained detectable precious metals in amounts many orders of magnitude greater than what existed in the material 12 prior to processing.

[0074] Further results obtained using Mt Willis material with a head grade value of 0.35mg/kg and 0.36mg/kg are shown in Table 2.

[0075] Table 2 -Additional results from processing of tailings in apparatus 10

[0076] These examples demonstrate that the apparatus 10 and processes described herein allow for the separation of metals from their host, to be agglomerated to detectable, therefore recoverable metals.

[0077] The apparatus 10 and processes described herein can be used, with catalysts, to electromechanically process material 12 from one state to another. The present applicant has demonstrated this with PFAS, where the waste contaminate was treated by in the apparatus 10 and calcium carbonate for the PFAS output to be reported as below detectable limits.

[0078] PFAS contaminated soil samples were used in two trials conducted on the control material; PFAS control sample is listed as SSI-04-001 ASS1-04-001 B; with caustic soda (NaOH) and hydrogen peroxide (H2O2) catalysts added, and SS 1-04-001 C; with caustic soda (NaOH) only. The results are shown in Table 3.

[0079] Table 3 - Treatment ofPFAS contaminated soil in apparatus 10

Method Name Perfluoronated Surfactants in Soil - TOPA

Job Number ME315273 Sample Name ME315273.001 ME315273.002 ME315273.003

PF AS Testing Description SS 1-04-001 A SS 1-04-002 B SS 1-04-003 C Sample Date 10/6/2020 10/6/2020 10/6/2020 Matrix Soil Soil Soil

Analyte Name Units Reporting Limit Result Result Result

% Moisture 1 45.8 31.3 44.6

PFOS and PFSOA Samples

Post-Perfluorooctane sulfonate (PFOS) mg/kg 0.0032 0.31 <0.0032 0.13

Post-Perfluoroctane sulfonamide (PFOSA) mg/kg 0.0032 <0.0032 <0.0032 <0.0032

Pre-Perfluorooctane sulfonate (PFOS) mg/kg 0.0032 0.0059 <0.0032 <0.0032

Pre-Perfluoroctane sulfonamide (PFOSA) mg/kg 0.0032 <0.0032 <0.0032 <0.0032

Pre-(13C8-PFOS) Surrogate % 0 122 128 137

Post-(13C8-PFOS) Surrogate % 0 94 88 87

PFHxS Samples

Post-Perfluorohexane sulfonate (PFHxS) mg/kg 0.0032 0.032 <0.0032 0.0055

Pre-Perfluorohexane sulfonate (PFHxS) mg/kg 0.0032 0.054 <0.0032 0.0100

Pre-(13C3-PFHxS) Surrogate % 0 123.000 123 129.0000

Post-(13C3-PFHxS) Surrogate % 0 101.000 102 94.0000

Post-Sum PFOS and PFHxS mg/kg 0.0032 0.34 <0.0032 0.13

[0080] The test results show sample B results were below LOR (limit of recording) of <0.0032 for

PFOS, PFSOA, PFHxS and PFBS.

[0081] Based on multiple testing of ores and tailings, the present applicant has developed an apparatus 10 and process that is simple, robust, tolerant of inhomogeneous contamination, and is applicable to small through to industrial-scale applications.

[0082] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.

[0083] It will be understood that the terms “comprise” and “include” and any of their derivatives (e.g. comprises, comprising, includes, including) as used in this specification, and the claims that follow, is to be taken to be inclusive of features to which the term refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied.

[0084] In some cases, a single embodiment may, for succinctness and/or to assist in understanding the scope of the disclosure, combine multiple features. It is to be understood that in such a case, these multiple features may be provided separately (in separate embodiments), or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise stated or implied. This also applies to the claims which can be recombined in any combination. That is a claim may be amended to include a feature defined in any other claim. Further a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0085] It will be appreciated by those skilled in the art that the disclosure is not restricted in its use to the particular application or applications described. Neither is the present disclosure restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the disclosure is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.