WO2023158297A1

WO2023158297A1 - Method for detection of minerals using fiber bragg grating-geoelectric hybrid sensing

Info

Publication number: WO2023158297A1
Application number: PCT/MY2023/050008
Authority: WO
Inventors: Noorhana Yahya
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-02-16
Filing date: 2023-02-10
Publication date: 2023-08-24
Anticipated expiration: 2024-08-16

Abstract

Accordingly, embodiments herein discloses a method for detection of mineral using fiber Bragg grating (FBG) sensor (100); comprising the steps of providing a fiber optic electromagnetic (EM) field sensor for measurements of EM field with effective refractive index (Ƞ_eff) alterations based on the EM characteristics of coating nanoparticles, wherein the effective refractive index (Ƞ_eff) of coating magnetic nanomaterial changes as it detects the minerals such that the alterations of FBG's effective refractive index (Ƞ_eff) causes a Bragg wavelength 0 shift (Δλ_Bragg). Further, the method involves enabling the FBG (100) using electric source to detect the changes in the effective refractive index (Ƞ_eff) through the mobilization of dissolved minerals in clay medium.

Description

METHOD FOR DETECTION OF MINERALS USING FIBER BRAGG GRATING-GEOELECTRIC HYBRID SENSING

FIELD OF THE INVENTION

The present disclosure relates to a method for detection of mineral using fiber Bragg grating (FBG) sensor in presence of electromagnetic (EM) field.

BACKGROUND OF THE INVENTION

This section is intended only to provide background information pertaining to the similar field of the present invention, and may be used only to enhance the understanding of the present invention and not as admissions of prior art.

At present solutions to mineral prospecting and exploration involve a process of geochemical sampling, drilling and geophysical surveys in unproven or fully exploited areas. Different types of geophysical surveys measure various physical properties of the Earth and have different applications and equipment. Geophysical surveys include seismic, magnetic, radiometric, or gravity surveys. Seismic surveys measure vibration as it passes through the Earth. Ground-based seismic surveys use the principles of seismology (earthquakes) to create a picture of the geology beneath the surface. Magnetic surveys measure the variations of the Earth's magnetic field due to the presence of magnetic minerals. Radiometric surveys measure gamma rays, which are continuously being emitted from the Earth by the decomposition of some common naturally occurring radiogenic minerals. Gravity surveys measure the gravity field to determine changes in rock density in the Earth's crust to detect small changes in the field, to interpret and map the locations of different rocks or geological formations which have different densities. The geophysical surveys mentioned are costly as they require much resources to perform, and time consuming.

At molecular level, the non-radioactive rare earth elements (NR-REE) occur as trivalent cationic state (RE3+) adsorbed onto clays. The RE3+ ions are readily extracted via simple leaching techniques. Over the years, NR-REE mining and extraction from ion-adsorption clay (IAC) sources has evolved from open cut (barrel/pool and heap leaching technologies) to a more environment friendly in- situ leaching (ISL) technology. The ISL has gained popularity as the technology of choice owing to minimum surface forest clearing (without the removal of topsoil). This technique commonly employs monovalent lixiviant such as ammonium sulfate ((NH4)2SO4) in low concentrations.

The NR-REE extraction process involving 3-5% (NH4)2SO4) aqueous solution is injected through a network of injection holes and collection piping is cost effective and relatively easy to operate. Although the ISL is far superior to heap leaching, the effect on environment persists.

There are few prior art documents disclosed here for the method for detection of minerals using a fiber Bragg grating sensor.

US patent number 7268884 discloses devices and methods of accurately determining optical wavelengths, such as the Bragg wavelengths of an FBG sensor array. Wavelength-swept light having a characteristic spectrum is swept over a bandwidth and is applied to an interference filter. The interference filter produces an optical spectrum having one or more reference peaks that are identifiable because of the characteristic spectrum. The optical spectrum is converted into electrical signals having at least one electrical signal that is identifiable because of the characteristic spectrum. The identifiable electrical signal is used by a signal processor as an absolute, high accuracy wavelength reference. Temperature compensation or temperature stabilization can compensate the characteristic wavelength. Fiber Bragg sensor systems can use the wavelength reference to determine the Bragg wavelength of FBG elements. The characteristic spectrum can be imparted by the light source or an optical element such as a transmission line filter.

US patent number 8781265 discloses a sensor for measuring forces and/or moments on an object, including at least one sensor element for the detection of an expansion of the object in at least one spatial direction, from which expansion a force or a moment can be determined, wherein the sensor element including an optical fiber with a sensor region with a fiber Bragg grating is provided, and the fiber Bragg grating is adapted to be irradiated with light, preferably a broadband light, generating a reflected light having a peak wavelength. The optical fiber is formed by a fiber core and at least one sheath of light-guiding material surrounding the fiber core. The fiber Bragg grating is arranged in the fiber core. The material of the sheath is doped with a fluorescent material and the fluorescent material may be irradiated with an excitation radiation to generate a fluorescent radiation having at least one main emission wavelength.

Japanese patent publication number 2010276343 discloses a soil grain measuring system including an FBG sensor disposed in a direction orthogonal to a direction with soil grains flowing therein, an FBG analyzer for detecting the amount of distortion caused by the collision of grains from an optical signal of Bragg wavelength output from the sensor, and a soil grain controller/monitor for determining the grain size of the soil grains and the amount of drift sand from the value of a detected amount of distortion. By the controller/monitor, an assumed value on the grain size of the soil grain is determined from the value of the detected amount of distortion to calculate the kinetic energy of the soil grains when they collide with the FBG sensor with respect to the assumed value and an expected value of the kinetic energy, determining the grain size of the soil grains and the amount of drift sand from the kinetic energy of the assumed value causing a difference between the kinetic energy and the expected value of the kinetic energy to fall within a prescribed allowable range.

The present invention seeks to overcome the above-mentioned limitations for mineral prospecting and exploration.

SUMMARY OF THE INVENTION

As will be realized in the following description, the invention is capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the scope of the present invention.

There is a need to provide unique method for detection of minerals using fiber Bragg grating (FBG) sensor. The FBG based electromagnetic (EM) field sensor for large-scale measurement for mineral detection done in-situ during exploration such that the EM emission interacts with the mineral and activates the surface energy of the minerals to improve recovery factor.

In an embodiment, the present invention relates to a method for detection of mineral using fiber Bragg grating (FBG) sensor. The present invention evaluates the performance of (FBG) sensor through an elucidation of the underlying sensing mechanism for monitoring the mobility of rare earth dissolve by the ionic liquid-based solution in the clay medium, in presence of electromagnetic (EM) field. The ionic liquid-based solution, can be chlorides, nitrates, sulphates or any ionic liquid-based solution in ionic form, but not limited to such. Examples of an ionic liquid-based compound are sodium chloride, ammonium sulphate, magnesium sulphate, but not limited to such.

In accordance with an embodiment relates to method for detection of mineral using fiber Bragg grating (FBG) sensor; comprising the steps of: applying an ionic liquid-based solution to a test bed to activate and leach a clay medium, for example Ion adsorption clay, of the test bed; applying AC and/or DC current into the ground to measure potential difference of the test bed to determine anomaly in the clay medium; and adding nano-particles in lixiviant agent to enhance charges in the clay layers for improved recovery of the minerals.

Accordingly, further the method involves conducting fabrication of fiber Bragg grating (FBG) using multimode fiber optics having different lengths by using a laser followed by partially cladding treatment and coating with magnetics/dielectric nano-particles sensing layers of plasmonic material; assembling at least one vertical and/or at least one horizontal FBG with different operating wavelengths at a test bed; and providing a fiber optic sensor (FBG) for measurements of EM field with effective refractive index (F|eff) alterations based on the EM characteristics of coating nanoparticles, wherein the effective refractive index (F|eff) of coating magnetic nanomaterial changes as it detects the minerals such that the alterations of FBG's effective refractive index (F|eff) causes a Bragg wavelength shift (AABragg).

Followed by enabling the FBG using electric source to detect the changes in the effective refractive index (F|_eff) through the mobilization of dissolved minerals in the clay medium.

Accordingly, the present invention evaluates the performance of the FBG sensor through an elucidation of the underlying sensing mechanism for monitoring the mobility of rare earth dissolve by the ionic liquid-based solution in the clay medium, in presence of EM field. Therefore, alteration of the effective refractive index (F|eff) of FBGs causes the Bragg wavelength shift (AABragg).

BRIEF DESCRIPTION OF THE DRAWINGS This invention will be described by way of non-limiting embodiments of the present invention, with reference to the accompanying drawings, in which:

Figure 1A, 1 B, 1 C illustrate schematic view of assembled structure of FBG sensor and EM field, according to an embodiment of the present invention.

Figure 2 illustrates schematic view of current flows for the present invention, according to an embodiment of the present invention.

Figure 3A, 3B illustrate schematic view of FBG sensor for the present invention, according to an embodiment of the present invention.

Figure 4 illustrates schematic view of dipole-dipole electrode configuration for the present invention, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, reference is made to the accompanying drawings where, by way of illustration, specific embodiments of the invention are shown. It is to be understood that other embodiments may be used, and other changes may be made without departing from the scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

In accordance with an embodiment of the present invention method for detection of mineral using fiber Bragg grating (FBG) sensor 100. The present invention evaluates the performance of FBG sensor 100 through an elucidation of the underlying sensing mechanism for monitoring the mobility of rare earth dissolve by ionic liquid-based solution, such as chlorides, nitrates, sulphates or any ionic liquid-based solution in ionic form, but not limited to such, in the clay medium, in presence of electromagnetic (EM) field 300. Examples of an ionic liquid-based compound are sodium chloride, ammonium sulphate, magnesium sulphate, but not limited to such. The Bragg wavelength shift (AABragg) can be caused by the alteration of the effective refractive index (F|eff) of FBGs with an accuracy of 0.01 nm being achievable.

Shown in Figure 1A, 1 B, 1 C is illustrating schematic view of assembled structure of FBG sensor 100 and EM field 300, according to an embodiment of the present invention. In the design, coating of a magnetic nanomaterial functions as an EM actuator will be carried out for the FBG to act as a sensor. The EM waves are irradiated for FBG sensor 100 to interact with the mineral. Accordingly, the present invention relates to a method for detection of mineral using fiber Bragg grating (FBG) sensor 100 comprising the steps of: applying an ionic liquid-based solution to a test bed to activate and leach a clay medium of a test bed; applying AC or/and DC current 200 into the ground to measure potential difference of the test bed to determine anomaly in the clay medium; adding nano-particles in lixiviant agent to enhance charges in the clay layers for improved recovery of the minerals; and conducting fabrication of fiber Bragg grating (FBG) using multimode fiber optics having different lengths by using a laser followed by partially cladding treatment and coating with magnetics/dielectric nano-particles sensing layers of plasmonic material.

Followed by assembling at least one vertical and/or at least one horizontal FBG with different operating wavelengths at a test bed; providing fiber optic sensor for measurements of EM field 300 with effective refractive index (F|eff) alterations based on the EM characteristics of coating nanoparticles. The effective refractive index (F|eff) of the coating of magnetic nanomaterial changes as it detects the minerals such that the alterations of FBG's effective refractive index (F|eff) causes a Bragg wavelength shift (AABragg). Further, the method involves enabling the FBG using electric source to detect the changes in the effective refractive index (F|eff) through the mobilization of dissolved minerals in a clay medium. The clay medium can consist of ion adsorption clay. The mineral can consist of a rare earth element (REE).

Shown in Figure 2, which illustrates schematic view of AC and/or DC current 200 flows, and Figures 3A and 3B illustrates schematic view of FBG sensor 100, for the present invention, according to an embodiment of the present invention. The electric dipole as the electric source enables the FBG sensor 100 to detect the changes in the effective refractive index (F|eff) through the mobilization of dissolved REE minerals in the clay medium, as shown in Figure 2. For example: the electric dipole is at range of 100 kHz - 1 .0 MHz, but not limited to such. The fabrication of fiber Bragg grating (FBG) is conducted by using multimode fiber optics having different lengths by using an excimer laser followed by partially cladding treatment and coating with sensing layers of plasmonic material. In an exemplary embodiment, four vertical and three horizontal FBGs are assembled with different operating wavelengths at a test bed. The plasmonic metamaterial provides a surface plasmon to achieve optical properties not seen in nature. The surface plasmon is produced from the interaction of light with metal-dielectric materials.

Further, the method comprises the step of developing a model on mobility detection of the dissolved REE minerals with respect to the effective refractive index (Qeff) alteration and Bragg wavelength shift (AABragg), in the presence of electromagnetic waves. The photon-magnon-polariton interaction occurs with the dissolved REE minerals mobility based on the Bragg wavelength shift (AABragg). For example, the different operating wavelengths are consisting of 1534, 1537, 1544, 1547, 1550, 1552, and 1554 nm, but not limited to such.

Accordingly, Hund’s rule states that every orbital in a sub-shell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin. It should also be noted that every orbital in a sublevel is singly occupied before any orbital is doubly occupied. All of the electrons in singly occupied orbitals have the same spin (to maximize total spin). In D Block of the periodic table of elements, the transition metal element block, there are maximum 5 shells that can be occupied. On the other hand, for the F Block of the periodic table of elements, the Rare Earth Element block, there are 7 shells that can be occupied by the electrons. Singlet to triplet conditions should, if not must, be met. The key fundamental of the present invention is that, each mineral has its characteristics that can be interpreted by the Bragg wavelength shift. The observation and consequently empirical model will be defining the type of F block or D block element of the periodic table of elements being detected. The Bragg wavelength shifts and amplitude indicates the anomaly detection. The strain induced by the optical fiber is also a resultant effect of bending displacement and vibration hence the phononmagnon (magneton Bohr) interaction. The frequency of such vibration depends on the minute force exerted by the flow of the leaching solution onto the FBG and also the density of the fluid, i.e., which also depends on the local Reynold’s number. The force field acting on the FBG is transverse at the fiber, resulting in changes in the Bragg wavelength. These changes permit the determination of the force of the flow acting on the fiber. The force field in the horizontal direction (x- axis) as well as vertical direction (y-axis) is obtained by the shift of fiber Bragg gratings in the optical fiber, as shown in Figure 2.

Multiphase Flow:

Kra - relative permeability of the fluid phase r_a - Viscosity of the phase

K - fluid permeability tensor

AP - tensor of pressure drop p_a - mass density of the fluid phase g - acceleration of gravity with the direction wavelength of Bragg

-effective refractive index, and A is the Bragg gratings' periodicity.

Where, p_e is the effective strain optic coefficient, Fm is the magnetic force, E is the Young's modulus, and A is the cross-sectional area.

Accordingly, the interaction of the current 200 and the response of the magnetic moment impacts the effective refractive index of the FBG and, as a result the Bragg wavelength shift. Accordingly, permeability of matter and electron, consequently the dielectric will likewise have an impact on the effective refractive index of the FBG and, as a result the Bragg wavelength shift. Magnetic, electric and pressure (Physical) forces will be impacting the shift. Magnon, photon and phonon interaction is the reasons to the shift.

As shown in Figure 4 which illustrates a schematic view of dipole-dipole electrode configuration for the present invention, according to an embodiment of the present invention. The fiber optic electromagnetic (EM) field 300 can be used to detect the REE minerals in river or water body. The optical sensing is important for monitoring the integrity of geological structures and the conditions of an environment, providing information on parameters, such as strain, veins, temperature, pressure, humidity, vibration, and chemical species (in this case REE mineral), among others. In the fibre optic sensors are attractive due to their compactness, immunity to electromagnetic interference, resistance to harsh operating conditions, and the possibility to implement in point and/or distributed configurations. The spectral response of fiber Bragg grating (FBG) changes especially in terms of a wavelength shift when it is exposed to a variation in strain, temperature, pressure, humidity, etc. As such, FBGs are a key enabling technology for fibre optic sensing. The FBG sensor 100 is a wavelength-encoded filter or reflector within a short segment of the core of an optical fibre that is illuminated through an ultra-violet (UV) laser beam. The high sensitivity, precision and resolution of the FBG sensor 100 provides a cost-effective method in monitoring mineral, such as, REE, fluid mobility and subsurface environment.

In accordance with the following advantages of the present invention: the invention is provided to the fiber Bragg grating (FBG) sensor 100 that effectively detects the rare earth element (REE) minerals. The FBG sensor 100 is provided within a short segment of the core of an optical fibre that is illuminated through a ultra-violet (UV) laser beam their high sensitivity, precision and resolution make it a cost-effective method in monitoring mineral. Followed by, the present invention provides the reduced lixiviant consumption, controls and prevents the pollution to ground and surface water, and improves the REE production efficiency.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

Claims

CLAIMS A method for detection of mineral using fiber Bragg grating (FBG) sensor (100); comprising the steps of: applying an ionic liquid-based solution to a test bed to activate and leach a clay medium of a test bed; applying AC or/and DC current (200) into the ground to measure potential difference of the test bed to determine anomaly in the clay medium; adding nano-particles in lixiviant agent to enhance charges in the clay layers for improved recovery of the minerals; conducting fabrication of fiber Bragg grating (FBG) using multimode fiber optics having different lengths by using a laser followed by partially cladding treatment and coating with magnetics/dielectric nano-particles sensing layers of plasmonic material; assembling at least one vertical and/or at least one horizontal FBG with different operating wavelengths at a test bed; providing a fiber optic sensor for measurements of electromagnetic (EM) field (300) with effective refractive index (F|eff) alterations based on the EM characteristics of coating nanoparticles, wherein the effective refractive index (F|eff) of coating magnetic nanomaterial changes as it detects the minerals such that the alterations of FBG's effective refractive index (F|eff) causes a Bragg wavelength shift (AABragg); and enabling the FBG using electric source to detect the changes in the effective refractive index (F|_eff) through the mobilization of dissolved minerals in the clay medium. The method as claimed according to claim 1 further comprising the step of developing a model on mobility detection of the dissolved minerals with respect to the effective refractive index (F|eff) alteration and Bragg wavelength shift (AABragg), in the presence of electromagnetic waves. The method as claimed according to claim 2, wherein photon-magnon- polariton interaction occurs with the dissolved minerals mobility based on the Bragg wavelength shift (AABragg).

4. The method as claimed according to claim 1 , wherein the ionic liquidbased solution can be chlorides, nitrates, sulphates, or any ionic liquidbased solution in ionic form.

5. The method as claimed according to claim 1 , wherein the FBG sensor (100) is a wavelength-encoded filter or reflector within a short segment of the core of an optical fiber that is illuminated through an ultra-violet (UV) laser beam.

6. The method as claimed according to claim 1 , wherein the fiber optic electromagnetic (EM) field (300) is to detect the minerals in river or water body.

7. The method as claimed according to claim 1 , wherein the clay medium is consisting of ion adsorption clay.

8. The method as claimed according to claim 1 , wherein the mineral is consisting of a rare earth element (REE). 9. The method as claimed according to claim 1 , wherein the ionic liquidbased compound can be sodium chloride, ammonium sulphate, magnesium sulphate.