A method for making nanoparticles from natural minerals using high-pressure water jets

Abstract

The present invention discloses a method for making a nanoparticle from natural minerals using high-pressure water jets. The method demonstrated the spontaneous formation of nanoparticles from minerals such as garnet and quartz, resulting in particles similar to nanoparticles found in soil. The process involved jetting water at pressures ranging from 10,000 to 50,000 psi (MPa) along with mineral particles of minerals of millimetre size, resulting in rapid disintegration and subsequent formation of nanoparticles. The invention provided insights into natural phenomena and processes contributing to soil formation. The invention offers a novel, efficient, and environmentally sustainable approach to nanoparticle synthesis from naturally abundant mineral resources.

Description

[0001] COMPLETE SPECIFICATION

[0002] TITLE OF THE INVENTION

[0003] A METHOD FOR MAKING NANOPARTICLES FROM NATURAL MINERALS USING HIGH-PRESSURE WATER JETS

[0004] FIELD OF THE INVENTION

[0005] The present invention relates to formation of nanoparticles, more specifically relates to a method for the efficient disintegration of natural minerals into nanoparticles utilizing high- pressure water jets.

[0006] BACKGROUND OF THE INVENTION

[0007] Traditionally, the synthesis of nanoparticles has involved a range of chemical and physical methods, including sol-gel processes, chemical vapor deposition, and mechanical milling. While effective, these methods often entail high energy consumption, the use of hazardous chemicals, and complex processing steps. Furthermore, many conventional techniques require post-processing to achieve the desired nanoparticle size and distribution, which adds to the overall cost and environmental impact.

[0008] The utilization of high-pressure water jets for material disintegration offers a promising alternative to traditional nanoparticle synthesis methods. High-pressure water jet technology, originally developed for applications such as cutting, cleaning, and surface preparation, employs a focused stream of water at extremely high pressures to erode and cut objects. This technique is inherently clean, as it primarily relies on water and mechanical energy, and does not require the introduction of additional chemicals or reagents. In cutting, macroscopic abrasive particles are used as part of the water jets. Impact of the water jet with the abrasive particles on the cutting target can break the particles, which has been observed before. However, the sizes of resulting particles are always above 50 micrometres (Chen, Duan, Wei, Wang, & Ni, 2019). Besides, the disintegration of natural minerals into nanoparticles in water jets themselves, without impact on the cutting target, has not been explored. Such an approach can provide valuable insights into geological processes, such as soil formation.

[0009] SUMMARY OF THE INVENTION The present invention relates to a method for the conversion of natural minerals into nanoparticles using high-pressure water jets.

[0010] In one embodiment, the present invention relates to a method for the efficient disintegration of natural minerals into nanoparticles utilizing high-pressure water jets. The method demonstrated the spontaneous formation of nanoparticles from minerals such as garnet and quartz, resulting in particles similar to nanoparticles found in soil. The process involved jetting water at pressures ranging from 10,000 to 50,000 psi (approximately 69-340 MPa) along with particles of minerals of millimeter size, resulting in rapid disintegration and subsequent formation of nanoparticles. The invention provided insights into natural phenomena and processes contributing to soil formation.

[0011] Other aspects of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learnt by the practice of the invention.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic representation of the experimental set-up for the formation of nanoparticles. 1-suspension of mineral particles in water; 2- Water recycling; 3- Nozzle; 4- Jet and 5- Sediment after spray.

[0014] Figure 2 Scanning electron microscopy images of A) garnet of 80 mesh size and B) nanometer sized garnet particles resulting from the water jet experiment. The reduced size indicates that the particles are broken in water jet.

[0015] Figure 3 Transmission electron microscopy (TEM) images of nanometer sized garnet particles formed from the 80 mesh size particles through a water jet. The sizes measured in TEM corresponds to the sizes in SEM.

[0016] Figure 4 Field emission scanning electron microscope (FESEM) images illustrates the timedependent sedimentation of garnet particles suspended in a water jet operating at a pressure of 30,000 psi, corresponding to a rotational speed of 1244 RPM. The abrasive flow rate was 20.4 kg / hour. The sedimentation process was observed over different time intervals: (A) 0 h, (B) 1 h, (C) 6 h, (D) 10 h, and (E) 24 h.

[0017] Figure 5 Field emission scanning electron microscope (FESEM) images illustrates the timedependent sedimentation of garnet particles suspended in a water jet operating at a pressure below 30,000 psi, corresponding to a rotational speed of 1086 RPM. The abrasive flow rate was 20.4 kg / hour. The sedimentation process was observed over different time intervals: (A) 0 h, (B) 1 h, (C) 6 h, (D) 10 h, and (E) 24 h.

[0018] Figure 6 Field emission scanning electron microscope (FESEM) images illustrates the timedependent sedimentation of garnet particles suspended in a water jet operating at a pressure below 30,000 psi, corresponding to a rotational speed of 756 RPM. The abrasive flow rate was 20.4 kg / hour. The sedimentation process was observed over different time intervals: (A) 0 h, (B) 1 h, (C) 6 h, (D) 10 h, and (E) 24 h.

[0019] Figure 7 A) Powder X-ray diffraction pattern of garnet before and after the water jet experiment, showing unchanged composition. (B) The (400) peak exhibits FWHM values of 0.122° (before) and 0.193° (after), and (C) the (420) peak shows FWHM values of 0.168° (before) and 0.188° (after), respectively.

[0020] Figure 8 Dynamic light scattering (DLS) illustrates the time-dependent sedimentation of wide range of garnet particles at A) Pl, B) P2, and C) P3 from 0 to 10 hours.

[0021] Figure 9 Transmission electron microscope (TEM) and HRTEM images showing nanometer sized garnet particles (A, B) at Pl corresponding (611) plane with interplanar distance of 1.86 A, (A, B) at P2 corresponding (422) plane with interplanar distance of 2.35 A, and (A,B) at P3 corresponding (431) plane with interplanar distance of 2.26 A.

[0022] Figure 10 Raman spectra of garnet before and after water jet treatment showing identical peak positions, indicating preservation of chemical structure.

[0023] Figure 11 Field emission scanning electron microscope (FESEM) images illustrates the timedependent sedimentation of quartz particles suspended in a water jet operating at a pressure of 30,000 psi, corresponding to a rotational speed of 1244 RPM. The sedimentation process was observed over different time intervals: (A) 0 h, (B) 1 h, (C) 6 h, (D) 10 h, and (E) 24 h.

[0024] Figure 12 Dynamic light scattering (DLS) illustrates the time-dependent sedimentation of wide range of quartz particles at pressure of 30000 psi corresponding to rotational RPM of 1244 from 0 to 10 hours.

[0025] Figure 13 A) Transmission electron microscope (TEM) images of nanometer sized sedimented quartz particles formed from the sand quartz particles through a water jet at a pressure of 30000 psi corresponding to a rotational speed of 1244 RPM, B) HRTEM showing the lattice plane (Oi l) with interplanar distance of 3.34 A. Figure 14 Powder X-ray diffraction pattern of quartz before and after the water jet experiment, showing characteristic unchanged composition and intact peaks before and after reduction in particle size.

[0026] Figure 15 Raman spectra of quartz before and after water jet treatment showing characteristic identical peak positions, indicating preservation of chemical structure.

[0027] Referring to the drawings, the embodiments of the present invention are further described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated or simplified for illustrative purposes only. One of ordinary skill in the art may appreciate the many possible applications and variations of the present invention based on the following examples of possible embodiments of the present invention.

[0028] DETAILED DESCRIPTION OF THE INVENTION

[0029] The following description is presented to enable any person skilled in the art to make and use the embodiments, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the present invention. Thus, the present invention is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0030] The present invention pertains to a method for the efficient conversion of natural minerals of millimeter- sized particles into nanoparticles utilizing high-pressure water jets. This innovative approach offered a sustainable and rapid means of nanoparticle synthesis with potential applications across various industries. Water used in the process can be recycled and only power is needed for the process which may be obtained from renewable sources.

[0031] Experimental details

[0032] The invention presents a novel method for the conversion of natural minerals into nanoparticles using high-pressure water jets. Natural minerals like garnet, silica and alumina particles of 80 mesh size were utilized, and the water jet was directed through a nozzle of a specified diameter of 0.35 mm. The silica used was quartz, one of its crystallographic forms. Other forms of silica such as amethyst was also used. Alumina exists in various crystallographic forms such as corundum (a-ALzOs), y- AI2O3, 8-AI2O3, P-AI2O3. The pressure of the water jet was carefully controlled to achieve optimal disintegration while minimizing energy consumption. The consumption rate of the mineral feedstock and the volume of product water collected were monitored during the experiments. Following disintegration, the resulting slurry of nanoparticles and residual particles was collected in a reservoir for further analysis. The slurry was allowed to settle for a designated period to facilitate the separation of nanoparticles from larger particles. The sedimented material was subjected to microscopy for further characterization.

[0033] Example

[0034] Garnet of 80 mesh size was purchased from the local marketplace, and quartz sand was collected from the river bed of Besant Nagar beach, Chennai (part of Bay of Bengal). Samples of garnet and quartz sand was washed repeatedly with water to remove any kind of impurities and dried and suspended in water jet. The invention demonstrates a method for particle size reduction of garnet and quartz abrasive materials in water jet, wherein operational parameters comprising water pressure levels Pi, P2, and P3 were systematically applied. These pressure regimes correlated with rotational velocities of 30000 psi for 1244 RPM, and below 30000 psi for 1086 RPM and 756 RPM, respectively. The abrasive flow rate of 20.4 kilograms per hour under these optimized conditions.

[0035] 10 kg of 80 mesh garnet was taken in the sample holder and suspended along with ultrapure reverse osmosis collected water at a very high pressure Pi of 30000 psi corresponding to rotational speed 1244 RPM in water jet and collected in a reservoir filled with water to avoid any kind of hole in the reservoir. Following disintegration, the resulting slurry of nanoparticles and residual particles was collected in a reservoir for further analysis. The slurry was allowed to settle for a period of 2 days to facilitate the separation of nanoparticles from larger particles. The supernatant water was thrown out of the reservoir and the particles sedimented at the bottom was collected and took for further characterization. The process was repeated with the same amount of 80 mesh garnet but at a pressure of P2 and P3 that are below 30000 psi and corresponding to rotational speed of 1086 RPM and 756 RPM of the pump. The sedimented particles were collected for two days and taken for further characterization.

[0036] 10 kg of quartz particles from sand was taken in the sample holder and suspended in water jet at a pressure of 30000 psi corresponding to rotational speed of 1244 RPM of the pump and collected in a reservoir filled with ultrapure water for two days and supernatant was thrown and the sedimented particles were taken for further characterization.

[0037] Characterization

[0038] Time-dependent studies on the sedimented particles were done to understand the behaviour and characterization was done by FESEM, TEM, DLS, powder XRD and Raman spectroscopy. These analytical techniques confirmed that the nanoparticles retained the mineralogical composition of the original minerals, indicating a preservation of chemical integrity throughout the disintegration process. Furthermore, the experiments demonstrated a pressure-dependent relationship, wherein variations in pressure resulted in changes in disintegration time and nanoparticle size. Lower pressures necessitated longer disintegration times and yielded larger nanoparticles, while higher pressures accelerated the disintegration process, leading to the formation of smaller nanoparticles. The water jet spray also resulted in the formation of dissolved ions, which were detected by ICP-MS.

[0039] Field Emission Scanning Electron Microscope (FESEM) imaging was employed to investigate the time-dependent sedimentation behavior of garnet abrasive particles suspended in a high-pressure water jet stream. In a first configuration, the water jet operated at a pressure of approximately 30,000 psi, with a corresponding nozzle rotational speed of about 1244 revolutions per minute (RPM) Figure 4. In a second configuration, the operating pressure was below 30,000 psi, with a corresponding rotational speed of approximately 1086 RPM, Figure 5. In third the operating pressure was below 30,000 psi, with a corresponding rotational speed of 756 RPM, Figure 6. In all these configurations, the abrasive flow rate was maintained at approximately 20.4 kilograms per hour. Sedimentation behavior was observed and recorded at multiple time intervals to assess the dispersion stability, settling characteristics, and influence of operational parameters on abrasive particle behavior during water jet processing. Figure 11 shows FESEM images of quartz particles suspended in a water jet operating at a pressure of 30,000 psi, corresponding to a rotational speed of 1244 RPM. The sedimentation process was observed over different time intervals.

[0040] Powder X-ray diffraction (XRD) analysis was conducted to assess the structural integrity and phase composition of garnet abrasive particles before and after exposure to the water jet process. The diffraction patterns obtained for both conditions revealed no significant change in the overall composition, indicating that the garnet retained its crystalline structure following high-pressure jet exposure. Detailed examination of specific diffraction peaks showed minor variations in peak broadening. The (400) reflection exhibited a full width at half maximum (FWHM) value of approximately 0.122° prior to the water jet experiment and 0.193° thereafter. Similarly, the (420) reflection demonstrated FWHM values of approximately 0.168° before and 0.188° after water jet exposure shown in Figure 7. Figure 12 shows the diffraction pattern of quartz before and after the water jet experiment, showing characteristic unchanged composition and intact peaks before and after reduction in particle size.

[0041] Dynamic Light Scattering (DLS) analysis was performed to investigate the time- dependent sedimentation behavior of a broad size distribution of garnet particles under three different process conditions, denoted as Pl, P2, and P3. The measurements were carried out over a duration ranging from 0 to 10 hours. At each condition (Pl, P2, and P3), the temporal evolution of particle size distribution and sedimentation dynamics was recorded to assess dispersion stability shown in Figure 8. Figure 13 shows DLS analysis of the time-dependent sedimentation of wide range of quartz particles at pressure of 30000 psi corresponding to rotational RPM of 1244 from 0 to 10 hours. The data indicated variation in sedimentation rates across the three conditions, providing insights into the influence of process parameters on the suspension behavior of garnet and quartz particles within the aqueous medium.

[0042] Figure 9 shows the Transmission Electron Microscopy (TEM) and High-Resolution TEM (HRTEM) imaging of the morphology and crystallographic features of garnet particles at the nanoscale under three distinct process conditions: Pl, P2, and P3. The images revealed well- dispersed garnet nanoparticles with clear lattice fringes indicative of crystalline order. At condition Pl, the HRTEM images identified lattice fringes corresponding to the (611) crystallographic plane, with an interplanar spacing of approximately 1.86 A. Under condition P2, the observed lattice fringes matched the (422) plane, exhibiting an interplanar distance of about 2.35 A. For condition P3, the garnet nanoparticles displayed lattice fringes corresponding to the (431) plane, with an interplanar spacing of approximately 2.26 A. Figure 14 shows the morphology of quartz particles subjected to high-pressure water jet treatment. The water jet operated at a pressure of approximately 30,000 psi, with a corresponding nozzle rotational speed of about 1244 revolutions per minute (RPM). The TEM images revealed the formation of nanometer-sized sedimented quartz particles derived from initial sand-grade quartz. Further high-resolution analysis using HRTEM confirmed the crystalline nature of the nanoparticles. Lattice-resolved imaging displayed distinct fringes corresponding to the (Oi l) crystallographic plane, with an interp lanar spacing measured at approximately 3.34 A. These results demonstrate the capability of the high-pressure water jet process to fragment bulk quartz into stable nanocrystalline particles while preserving crystallographic integrity.

[0043] Figure 10 shows Raman spectra of garnet before and after water jet treatment with identical peak positions, indicating preservation of chemical structure. Figure 15 shows Raman spectra of quartz before and after water jet treatment showing characteristic identical peak positions, indicating preservation of chemical structure.

[0044] The morphology of the minerals such as garnet and quartz before and after the water jet clearly state that the initial mm-sized particles formed nano-sized particles when subjected to the water jet spray.

[0045] Thus the present invention relates to a method for the conversion of natural mineral particles into nanoparticles using high-pressure water jet technology. Specifically, the invention demonstrates that minerals such as garnet and quartz, initially present in millimeter -sized form, undergo significant size reduction to the nanometer scale upon exposure to high-pressure water jet spray. Morphological analysis conducted before and after treatment using characterization techniques such as FESEM, TEM, and HRTEM confirms the transformation from bulk to nanoscale particles.

[0046] The invention offers a novel, efficient, and environmentally sustainable approach to nanoparticle synthesis from naturally abundant mineral resources. This water jet -based technique eliminates the need for chemical reagents or high-temperature processing, thereby reducing environmental impact and energy consumption.

[0047] In addition to its implications for materials processing, the method provided insights into geological processes contributing to soil formation and offered a sustainable approach for nanoparticle synthesis from abundant mineral resources. The invention suggests potential applications in various fields, including materials science, environmental remediation, agriculture and construction.

[0048] It may be appreciated by those skilled in the art that the foregoing drawings, examples and experimental evidences are merely illustrative and are not to be taken as limitations upon the scope of the invention.

Claims

We Claim:

1. A method of making nanoparticles from natural minerals, comprising: a. introducing millimeter- sized natural mineral particles suspended along with water into a high-pressure water jet system; b. forcing the suspended particles through a nozzle of the water jet system with optimized pressure and the flow rate to produce a slurry comprising nanoparticles and residual particles; characterized in that, the pressure of water jet induces rapid disintegration of the millimetersized mineral particles into nanoparticles.

2. The method as claimed in claim 1, wherein the natural minerals includes garnet, quartz, corundum.

3. The method as claimed in claim 1, wherein the mineral particles are of 80 mesh size.

4. The method as claimed in claim 1 , wherein the high-pressure water jet system with pressures ranging from 10,000 to 50,000 psi.

5. The method as claimed in claim 1, wherein the high-pressure waterjet operating at rotational speed between 740 RPM to 1300 RPM.

6. The method as claimed in claim 1, wherein the nozzle diameter is 0.35 mm.

7. The method as claimed in claim 1, wherein the abrasive flow rate is maintained at approximately 20.4 kilograms per hour during the waterjet operation.

8. The method as claimed in claim 1, wherein the slurry is allowed to settle for a two days to separate nanoparticles from larger particles.

9. The method as claimed in claim 1, wherein the minerals such as garnet, quartz, corundum exists in various crystallographic forms.

10. The method as claimed in claim 1, wherein the mineral particles are a mixture of minerals.

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