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WO2021028769A1 - Procédé et système d'extraction de nanomatériaux de dioxyde de titane à partir d'ilménite naturelle - Google Patents

Procédé et système d'extraction de nanomatériaux de dioxyde de titane à partir d'ilménite naturelle Download PDF

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Publication number
WO2021028769A1
WO2021028769A1 PCT/IB2020/057245 IB2020057245W WO2021028769A1 WO 2021028769 A1 WO2021028769 A1 WO 2021028769A1 IB 2020057245 W IB2020057245 W IB 2020057245W WO 2021028769 A1 WO2021028769 A1 WO 2021028769A1
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ilmenite
range
nanomaterials
autoclave
intermediate product
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Inventor
Professor Chandana Premakumara UDAWATTE
Mr. Rajakaruna Ananda Rajapaksha Panditha Wasala Mudiyanselage Tharindu Priyankara Bandara RAJAKARUNA
Professor Rajapakse Mudiyanselage Gamini RAJAPAKSE
Professor Rajapaksha Liyanarachchige Rohana CHANDRAJITH
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Vice Chancellor Sabaragamuwa University Of Sri Lanka
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Vice Chancellor Sabaragamuwa University Of Sri Lanka
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D11/00—Solvent extraction
    • B01D11/02—Solvent extraction of solids
    • B01D11/0288—Applications, solvents
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/003—Titanates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/003—Titanates
    • C01G23/005—Alkali titanates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/02—Halides of titanium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
    • C01G23/0536—Producing by wet processes, e.g. hydrolysing titanium salts by hydrolysing chloride-containing salts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/10—Halides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
    • C22B34/1236—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching
    • C22B34/124—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching using acidic solutions or liquors
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
    • C22B34/1236—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching
    • C22B34/1259—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching treatment or purification of titanium containing solutions or liquors or slurries
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/02—Amorphous compounds
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
    • C01P2002/85—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by XPS, EDX or EDAX data
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
    • C01P2004/13—Nanotubes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
    • C01P2004/16—Nanowires or nanorods, i.e. solid nanofibres with two nearly equal dimensions between 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to field of preparing titanium dioxide nanomaterials. More particularly, the present invention relates to a process and system for extracting titanium dioxide nanomaterials from natural ilmenite.
  • Lanka Mineral Sands Limited fully owned by the Government of Sri Lanka, is the successor to Ceylon Mineral Sands Corporation, established under the Industrial Corporation Act in 1957.
  • the functions of the Lanka Mineral Sands Limited include mining, processing and exporting of heavy mineral beach sands.
  • the main deposits are found at Pulmoddai on the north eastern coast of Sri Lanka. These deposits are of high grade, comprising of over 80% heavy mineral content, with an approximate composition of 70-72% ilmenite, 8- 10% zircon, 8% rutile, 1% sillimanite and 0.3% monazite.
  • ilmenite The annual production of ilmenite, rutile, zircon, monazite and high- titanium ilmenite is approximately 90000, 9000, 5500, 100 and 4000 tonnes respectively.
  • Ilmenite is the dominant mineral present in these deposits and the amount estimated by the Geological Survey and Mines Bureau (GSMB) of Sri Lanka is around 6 - 8 million Metric Tonnes.
  • Ilmenite is chemically a combination of iron oxide and titanium dioxide with the formula FeO.TiOi with silicate impurities.
  • Pulmoddai mines of Lanka Mineral Sands Ltd. uses physical methods to separate crude mineral sands into components such as ilmenite, rutile and zircon etc. Such separated mineral sands are exported to foreign countries. China stands out as the top buyer of mineral sands mined in Sri Lanka, since 2008. India and Japan are the second and third ranked buyers, respectively. Sri Lanka annually exports the raw ilmenite mineral sand to the value of US$ 8 million from which the end user extracts US$ 160 million worth of T ⁇ q2 ⁇ This sum is equivalent to a value-addition of 20 times the price of the raw ilmenite that Sri Lanka currently exports to the end user.
  • Ti The titanium element discovered in 1791 was first made into metal in 1910.
  • the “Ti” metal has earned commercial demand since 1950s after it was named as the “wonder metal of the age”. “Ti” is the 9 th most abundant element on the Earth’s crust representing approximately 0.6% of elemental composition.
  • titanium dioxide nanoparticles are very important inorganic chemical material, especially the best- quality white pigment. Titanium dioxide pigments are used to enhance colours and quality from ancient times. They are inexpensive, chemically stable and absorption-active under UV irradiation. It has high whiteness, high refractive index and light scattering ability. These characteristics make T1O2 the predominant component of white pigments in paints, paper, plastics and rubber.
  • T1O2 Due to the unique characteristics of the titanium dioxide, it is also used in environmental purification, gas sensors, and in photovoltaic cells. Further, T1O2 is also used in pharmaceutical and cosmetic industries in large scale. Therefore, the demand for T1O2 is expected to grow within the next 5 to 10 years at a similar ration as that of the world economy.
  • a WIPO patent publication number 2004035841A1 discloses a sulfate process for producing titania from a titaniferous material.
  • the process includes leaching the titaniferous material and producing leach liquor, separating titanyl sulfate from leach liquor, hydrolysis of the extracted titanyl sulfate, and thereafter calcining the solid phase produced in the hydrolysis step.
  • the process is characterized by multiple stages leaching of the titaniferous material.
  • the said patent does not produce titanium dioxide materials of nanoparticles size. Further, the said patent discloses that that leaching is done by sulfuric acid, which is highly acidic in nature.
  • a research paper “Jayasekera, S., Marinovich, Y., Avraamides, J., & Bailey, S. L, Pressure leaching of reduced ilmenite : electrochemical aspects, 39, 183-199” discloses that a chloride process requires a higher-grade feedstock than the sulphate process, necessitating the upgrading of the ilmenite in an intermediate thermal production step to remove most of the iron and other impurities.
  • the said thermal reduction is required to be done in rotary kilns to produce synthetic rutile or in a furnace to create a titaniferous slag.
  • the thermally reduced product is then processed with chlorine to make a high-purity T ⁇ q2 ⁇ This leads to higher expense of operating the chloride process.
  • both the said processes demand elevated temperatures over 1000 °C and such high temperatures are maintained in electrical furnaces.
  • a debilitating factor in the operation of such a factory in middle income countries, such as Sri Lanka is the high electricity costs, as electricity is a major requirement to extract T1O2 from ilmenite sand by the said processes.
  • currently used sulphate and chloride processes only produce micrometer size particles and size reduction to nanoscale of 1 nm to 100 nm at least in one dimension by these processes have not been achieved.
  • nanomaterials have the inherent advantage of having significantly large surface area compared to micro- materials. For instance, 1 mg of 1 nm particles has the same surface area as 1 kg of 1 pm particles.
  • the process and system are required which may overcome above discussed drawbacks and provide easy to operate and a cost-effective method for extracting titanium dioxide nanomaterials.
  • the process and system should be able to operate at lower temperatures to extract pure titanium dioxide nanomaterials such as nano-rods and nanoparticles from natural ilmenite.
  • the process includes pre-treating the said ilmenite to form ilmenite particles having size in the range of 50-200 micrometer.
  • the pre-treating of the said ilmenite includes purifying the said ilmenite via a magnetic separator operating with forward angle and side angle in range of 1 -90° by applying voltage in range of 0-50 Volts and current in range of 0-10 Ampere, and milling by a dry ball mill to obtain the said ilmenite particles having size of 50-200 micrometers (mhi).
  • the process further includes leaching out iron from the said ilmenite particles by treating the said ilmenite particles with a first acid solution at predetermined hydrothermal conditions in a closed rotary system of an autoclave.
  • the first acid solution is aqueous hydrochloric acid
  • HC1 of molar range of 5-10 moldm , the said aqueous HC1 being filled in the autoclave operated at 100-300 °C, the said HC1 being in range of 50-90% volume of the said autoclave.
  • the process includes treating the resultant residue particles to obtain an intermediate product.
  • the treating of the resultant residue particles includes filtering the said resultant residue particles by cellulose nitrate membrane filter of pore size in the range of 0.1-2 micrometer (qm) to form sedimental intermediate product.
  • the said sedimental intermediate product is washed with aqueous hydrochloric acid (HC1) followed by the water to obtain hydrolyzed intermediate product, and dried by creating vacuum in a vacuum oven at a temperature condition in the range of 50°C-150°C.
  • HC1 aqueous hydrochloric acid
  • the process further may include treating the said intermediate product to extract the said titanium dioxide (T1O2) nanomaterials.
  • the said treatment of the said intermediate product includes reacting the said intermediate product with aqueous hydrogen peroxide (H2O2) in alkaline medium at a temperature condition in range of 30°C-100°C for 1-5 hours under a reflux technique to obtain titanium solution.
  • H2O2 aqueous hydrogen peroxide
  • the alkaline condition may be maintained by adding aqueous alkali solution comprising sodium hydroxide
  • the said aqueous sodium hydroxide (NaOH) is being added in range of 50-300 milliliter for lgram of the intermediate product.
  • the alkaline condition may be maintained by adding at least one of KOH, LiOH, RbOH, NH 4 OH, Ca(OH) 2 , Ba(OH) 2 , and Mg(OH) 2 .
  • aqueous hydrogen peroxide (H2O2) solution is added in range of 1-50 ml to react with the said intermediate product.
  • the process includes centrifuging to obtain a supernatant comprising the leached titanium compounds.
  • the said titanium compounds is mixed with a solution of hexadecyltrimethylammonium bromide in micelle concentration and water-alcohol at a temperature condition in the range of 50°C- 300°C for 1-5 hours.
  • the obtained mixture is processed, thereby extracting the said titanium dioxide (T1O2) nanomaterials with 100 % purity.
  • the said processing of the obtained mixture includes filtering, washing, and ultra-sonication by acetic acid and distilled water.
  • the resultant mixture is heated at 150°C to obtain amorphous titanium oxide (T1O2) nanomaterials, followed by calcination of the said amorphousTi0 2 nanomaterials to obtain the T1O2 nanomaterials of anatase phase and rutile phase.
  • T1O2 amorphous titanium oxide
  • the said calcination is carried at a temperature in the range of 300°C-500°C for 2-5 hours to obtain the titanium oxide (T1O2) nanomaterials of anatase phase.
  • the said calcination is carried at a temperature in the range of 600°C-800°C for 2-5 hours to obtain the titanium oxide (T1O2) nanomaterials of rutile phase.
  • the said nanomaterials are in a form of nanoparticles, nanorods, nanoflowers, nanoplates or like.
  • the present invention provides an apparatus, which is adapted to provide a closed system for carrying out the said process.
  • the apparatus includes a block base.
  • the apparatus further includes an autoclave having a stainless steel container, Teflon reaction vessel liner, a screw- fit Teflon lid, screw-fit stainless steel lid with Allen-key for leak-proof tightening, stainless steel weights and springs.
  • the apparatus further includes an electric oven housing the autoclave. Further, the said apparatus includes an autoclave holder for fitting the autoclave to the electric oven.
  • a rotational bar is connected to the electric oven with a plurality of ball bearings. Further, a rotating mechanism is adapted for rotating the said autoclave.
  • the rotating mechanism comprising a combination of belt system, sheave system and gear motor.
  • the present invention also provides a system for extracting nanomaterials from natural ilmenite at moderate conditions.
  • the system includes a magnetic separator adapted to purify the said ilmenite.
  • the said system further includes a dry ball mill adapted to mill pure ilmenite to obtain ilmenite particles.
  • the dry ball mill produces particles having size of 50-200 micrometers.
  • the system further includes an apparatus comprising an autoclave.
  • the said autoclave is adapted to leach out iron from the said ilmenite particles by treating the said ilmenite particles with a first acid solution at predetermined hydrothermal conditions to obtain resultant residue particles in a closed rotary system of the said autoclave.
  • the obtained resultant residue particles are treated to obtain intermediate product.
  • the said apparatus is adapted to treat the said intermediate product to extract the said titanium dioxide (T1O2) nanoparticles.
  • FIG. 1-lC illustrate flow charts depicting an exemplary process for extracting nanomaterials from natural ilmenite at moderate conditions, according to various embodiments of the present invention
  • FIG. 2 illustrates a schematic diagram of apparatus for carrying out the process for extracting nanomaterials from natural ilmenite at moderate conditions as described with reference to Fig.l, according to various embodiments of the present invention
  • FIG. 3 illustrates a schematic diagram of autoclave of the present invention, according to various embodiments of the present invention.
  • Fig. 4 illustrates a schematic diagram of nanorods formationwithin soft templated micelle structure, according to various embodiments of the present invention
  • Fig. 5 illustrates a graph representing an Energy Dispersive X-Ray (EDX) analysis of samples obtained vide the process, according to various embodiments of the present invention
  • Fig. 6 illustrates a graph representing powder X-ray diffractogrammes of samples obtained vide the process, according to various embodiments of the present invention
  • Fig. 7 illustrates a graph representing a Tauc plot of absorption data of the T1O2 product obtained vide the process, according to various embodiments of the present invention
  • Fig. 8 illustrates scanning electron microscopy (SEM) images of T1O2 samples obtained vide the process, according to various embodiments of the present invention
  • Figs. 9a & 9b illustrate scanning electron microscopy (SEM) images of T1O2 nanomaterials in form of nanowires obtained vide the process, according to various embodiments of the present invention
  • Figs. 10a & 10b illustrate scanning electron microscopy (SEM) images of TiOinanomaterials in form of nano-flowers obtained vide the process, according to various embodiments of the present invention
  • Figs. 11a- lid illustrate scanning electron microscopy (SEM) images of TiO nanomaterials in form of nanorods obtained vide the process.
  • Fig. 12 illustrates an exemplary block diagram representing system for extracting nanomaterials from natural ilmenite, according to various embodiments of the present invention.
  • the present invention relates to a process and system for extracting titanium dioxide nanomaterials from natural ilmenite at moderate conditions.
  • inventive aspects of the invention along with various chemical reactions and engineering involved, will now be explained with reference to Figs. 1-12 herein.
  • Fig.l illustrates a process for extracting titanium dioxide nanomaterials from natural ilmenite at moderate conditions according to the present invention. It will be apparent to a person skilled in the art that the term “ilmenite” used herein refers to naturally occurring ore of titanium, a metal needed to make a variety of high-performance alloys.
  • the ilmenite used for the purpose of this invention is sourced from Sri Lanka Mineral Sands Ltd. However, it should be clearly understood that the present disclosure may be employable for extracting titanium dioxide nanomaterials from any ilmenite raw material.
  • step (20) The process, according to various embodiments of the present invention, for extracting titanium dioxide nanomaterials from the natural ilmenite at moderate conditions starts with step (20).
  • the process involves pre-treating the said ilmenite to form pre-treated ilmenite particles.
  • the said ilmenite particles are sized in range of 50- 200 micrometer.
  • the said pre-treating involves purifying the said ilmenite via a magnetic separator, such as magnetic separator (16) shown in Fig. 12.
  • the said separator (16) operates with forward angle and side angle in range of 1-90° by applying voltage in range of 0-50 Volts and current in range of 0-10 Ampere in the said separator (16).
  • the said magnetic separator (16) is operated with forward angle of 19° and side angle 15° side angle by applying voltage 17.7 V and current of 0.3A to obtain pure ilmenite.
  • the magnetic separator (16) is specially designed to be adapted to carry out the separation as required for the present invention, the basic design elements thereof resemble those in conventional systems. Further, it should be understood that the operating parameters listed are of exemplary nature, and do not connote any limitation on the present invention.
  • the said purified ilmenite is milled by a dry ball mill (18) to obtain the said ilmenite particles preferably sized around 50-200 micrometers (pm) used in step (20).
  • the process flows to step (22).
  • the process involves leaching out iron from the said ilmenite particles by treating the said ilmenite particles with a first acid solution at predetermined hydrothermal conditions in a closed rotary system of the autoclave, such as rotary autoclave (15) shown in Fig.3.
  • the said first acid solution is an aqueous hydrochloric acid (HC1) of molar range of 5-10 moledm .
  • HC1 aqueous hydrochloric acid
  • the said aqueous HC1 is filled in the autoclave (15) in range of 50-90% volume of the said autoclave (15), and the said autoclave (15) is operated at 100-300 °C, for carrying out the treatment, with operating speed of round 1-60 revolutions per minute (rpm).
  • leaching carried out in present invention is explained with respect to first acid being HC1, said explanation should not be construed as a limitation, accordingly, the present invention is equally employable with leaching being carried out by other equivalent inorganic acids, such as hydrogen bromide acid (HBr), nitric acid (HNO 3 ), boric acid (H 3 BO 3 ), sulfuric acid (H 2 SO 4 ), carbonic acid (H 2 CO 3 ), phosphoric acid (H 3 PO 4 ), hydrofluoric acid (HF) and the like.
  • equivalent inorganic acids such as hydrogen bromide acid (HBr), nitric acid (HNO 3 ), boric acid (H 3 BO 3 ), sulfuric acid (H 2 SO 4 ), carbonic acid (H 2 CO 3 ), phosphoric acid (H 3 PO 4 ), hydrofluoric acid (HF) and the like.
  • the process (50) further involves treating the resultant residue particles obtained after step (22) to get an intermediate product.
  • the treating of the said residue particles includes first filtering the said resultant residue particles by cellulose nitrate membrane filter of pore size in the range of 0.1-2 micrometer (mhi) (WhatmanTM with (0.1-2) pm pore size) to form a sedimental intermediate product as shown in step 24(a) (refer Fig. 1A).
  • the so obtained sedimental intermediate product is then washed with an acid, such as aqueous hydrochloric acid (HC1), of strength 0.1-2 molar (M) followed by washing with water to obtain a hydrolyzed intermediate product (refer Fig. 1A).
  • an acid such as aqueous hydrochloric acid (HC1), of strength 0.1-2 molar (M) followed by washing with water to obtain a hydrolyzed intermediate product (refer Fig. 1A).
  • the said hydrolyzed intermediate product obtained at step 24(b) is dried at a temperature in the range of 50°C-150°C. Specifically, the said hydrolyzed intermediate product is dried at temperature of 70°C overnight in a vacuum oven by creating vacuum in the said oven to obtain the intermediate product (refer Fig. 1A).
  • the process (50) further involves treating the said intermediate product to extract the said titanium dioxide (Ti0 2 ) nanomaterials.
  • the process of treating of the intermediate product will now be explained with reference to Fig. IB.
  • the treatment of the said intermediate product involves reacting the said intermediate product with peroxide, such as 20-40 % aqueous hydrogen peroxide (H2O2), preferably 30 %
  • the treatment is carried out in an alkaline medium, such as with sodium hydroxide (NaOH), of around 0.1-2 M, at a temperature condition in range of 10°C-100°C for 1-5 hours under a reflux technique to obtain a resulting titanium solution.
  • an alkaline medium such as with sodium hydroxide (NaOH), of around 0.1-2 M, at a temperature condition in range of 10°C-100°C for 1-5 hours under a reflux technique to obtain a resulting titanium solution.
  • the intermediate product i.e. titanium residues reacts with oxidizing peroxide (H2O2) in alkaline condition maintained with NaOH according to reactions (5) & (6).
  • H2O2 oxidizing peroxide
  • the process leads to formation of titanium solution containing Na x Ti(0 2 )i(OH). Under these conditions, silica impurities may remain undissolved.
  • titanium oxide (T1O2) is an amphoteric oxide. Due to this, the said titanium oxide (T1O2) may react as an acid and base depending on the pH of the solution.
  • T1O2 acts as acid and reacts with NaOH (alkaline) to produce layered titanate of Na2Ti307 and 3 ⁇ 40 as shown below in reaction (7).
  • step (26b) the said titanium solution is centrifuged to obtain a supernatant containing titanium compounds (refer Fig. IB).
  • the solution is centrifuged for 20 min at 5000 rpm to obtain supernatant containing the leached titanium compounds (refer Fig. IB).
  • the said supernatant is mixed with the solution of hexadecyltrimethylammonium bromide (HDTMA) surfactant at a concentration above its critical micelle concentration and ethanol.
  • HDTMA hexadecyltrimethylammonium bromide
  • the process further includes subjecting the resultant to the hydrothermal treatment in the closed system of the autoclave (15) at a temperature condition in the range of 50°C-300°C for 1-5 hours, at step 26b (refer Fig. IB).
  • Fig. 4 represents a schematic diagram of the bunches of nanorods formation when a soft template of HDTMA-water is used at the critical micelle concentration of the surfactant HDTMA.
  • T1O 2 particles arrange in the spaces provided within the spherical micelle structure.
  • the process (50) involves processing of the said mixture obtained at step (26b), thereby extracting the said titanium dioxide (T1O 2 ) nanomaterials with 100 % purity.
  • the said obtained mixture i.e. white powder is filtered by a cellulose nitrate membrane filter (Whatman with (0.1-2) pm pore size) having a pore size in the range of 0.1-2micrometer (pm) (refer Fig. 1C).
  • the said filtered white powder is washed by ethanol and distilled water at step 26(ii).
  • the resultant white powder is ultra- sonicated by acetic acid and distilled water for formation of H 2 Ti 3 0 7 (s) as shown in reaction (8) (refer Fig. 1C).
  • tubular structures bust into small particles due to dehydration of inter-layered OH groups that destroy the nanotubes structure.
  • the decomposition of H2T13O7 nanotubes takes place to obtain T i02nanomaterials .
  • the calcination is carried at the temperature in the range of 300°C -500°C for 2-5 hours, preferably at 350 °C for 3 hours to obtain the titanium oxide (T1O2) nanomaterials of anatase phase.
  • the calcination is carried at the temperature in the range of 600°C -800°C for 2-5 hours, preferably at 650°C for 3 hours to obtain the titanium oxide (T1O2) nanomaterials of rutile phase.
  • the saidTiCLnanomaterials are in form of nanowires, nono-flowers, and nanotubes.
  • Fig.5 represents Energy Dispersive X-Ray (EDX) analysis of obtained samples.
  • EDX Energy Dispersive X-Ray
  • the purity of the as-prepared amorphous titanium dioxide is shown by its energy-dispersive X-ray (EDX) spectrum ofthe SEM image, which gives 33.33% titanium and 66.67% oxygen atomic percentages, thus confirming the 1:2. stoichiometry of the compound.
  • Fig. 6 represents powder X-ray diffractogrammes (XRD) of obtained samples.
  • the diffractogramm with blue line represents the titanium dioxide amorphous product.
  • Fig. 6b the P-XRD pattern is shown which represents the samples calcined at 350°C.
  • the diffraction peaks appearing at 25.58°, 38.15°, 48.42°, and 55.02° correspond to the (101), (004), (200), and (211) diffractions of pure anatase phase of titanium dioxide (Joint Committee on Powder Diffraction Standards (JCPDS) Card No. 21-1272), respectively (refer Fig.6b).
  • the P-XRD pattern of the samples calcined at 650°C contains peaks at 27.45°, 36.16°, 41.26°, 54.40°, and 56.70°, respectively. These peaks correspond to diffractions from the (110), (101), (111), (211), and (220) planes of the pure rutile phase of titanium dioxide (JCPDS Card No. 29-1360).
  • the crystallinity calculated from the XRD peak areas shows that amorphous, anatase, and rutile phases have, respectively, 24%, 90%, and 98% crystallinity percentages.
  • the crystallite sizes of the anatase and rutile phases, calculated using the Schemer’s equation, are 0.8 and 1.2nm, respectively.
  • Fig. 7 illustrates a graph representing Tauc plot of absorption data from the obtained T1O2 products.
  • the plot clearly shows the decrease in indirect band gap to 3.15eV when crystalline the product by calcining at temperature of 1000°C from amorphous phase.
  • Well crystalline product plot shows by T1O2 red line and amorphous product which before calcined product indicates by a-Ti02 black line.
  • Fig. 8 illustrates scanning electron microscopy (SEM) images of the obtained T1O2 samples. These images indicate that the as prepared sample has a flowerlike morphology (refer Fig. 8a). Further, the said sample is heat treated at 350°C to develop into a network of nanorods in the anatase phase (refer Fig. 8b).
  • the rutile phase obtained has individual TiC ⁇ nanorods (refer Fig. 8c).
  • Figs. 9a & 9b illustrate scanning electron microscopy (SEM) images of the obtained T1O2 nanomaterials in form of nanowires.
  • Figs. 10a &10b illustrate scanning electron microscopy (SEM) images of the obtained T1O2 nanomaterials in form of nano-flowers.
  • Figs. 11a- lid illustrate scanning electron microscopy (SEM) images of the obtained T1O2 nanomaterials in form of nanorods.
  • the diameters of anatase and rutile phase of nanorods are 32 and 67 nm, respectively, and ⁇ 350 nm long as calculated from the SEM images. Comparing these data with those obtained for the crystallite size from the XRD indicate that each nano-rod is composed of a large number of crystallites arranged in a rod like structure to form nanorods.
  • Fig.12 there is shown a system (1000) for extracting titanium dioxide nanomaterials from natural ilmenite at moderate conditions, which will now be explained with reference to a block diagram.
  • the system (1000) includes a magnetic separator (16) adapted to purify the said ilmenite to obtain the pure ilmenite.
  • the said magnetic separator (16) being operated with forward angle and side angle in range of 1-90° by applying voltage in range of 0-50 Volts and current in range of 0-10 Ampere in the said separator (16).
  • the system (1000) further includes a dry ball mill (18) adapted to mill pure ilmenite to obtain ilmenite particles or powdered ilmenite.
  • the said ilmenite particles are sized to 50-200 micrometers.
  • the system (1000) further includes an apparatus (100).
  • the said apparatus includes an autoclave (15) adapted to leach out iron from the said ilmenite particles powdered ilmenite by treating the said ilmenite particles with a first acid solution at predetermined hydrothermal conditions to obtain resultant residue particles in a closed rotary system of the said autoclave (15).
  • the autoclave (15) is adapted to provide a closed system for extracting the titanium oxide nanomaterials.
  • the said autoclave (15) may include stainless a steel container (5), Teflon reaction vessel liner (6), a screw-fit Teflon lid (4), screw-fit stainless steel lid with Allen-key for leak-proof tightening (1), stainless steel weights (3) and springs (2).
  • the said apparatus (100) includes an electric oven (12) housing the autoclave (15). Further, the apparatus (100) includes an autoclave holder (14) for fitting the autoclave (15) to the electric oven (12). Further, a rotational bar (7) connected to the electric oven (12) with a plurality of ball bearings (13) (refer Fig. 2). [00140] Furthermore, a rotating mechanism for rotating the said autoclave (15) may be provided. In an embodiment, the rotating mechanism may include a combination of belt system (9), sheave system (8) and gear motor (10) (refer Fig. 2).
  • the system (1000) includes a calcination device (19) adapted for heating the said mixture at 150°C to obtain amorphous titanium oxide (TiCF).
  • the said calcination device (19) is further adapted for the calcination of the said amorphous titanium oxide (T1O2) to obtain the titanium oxide (T1O2) nanomaterials of anatase phase and rutile phase.
  • Nano-crystalline titania (T1O2) has been intensively investigated due to its numerous applications in many fields such as electrode materials for solar cells, photo catalysts, wide band gap materials for gas sensing, pharmaceuticals, paints, and disinfectants.
  • the most important application areas are paints and varnishes as well as paper and plastics, which account for about 80% of the world's titanium dioxide consumption.
  • pigment applications such as printing inks, fibers, rubber, cosmetic products and food account for another 8%.
  • the rest is used in other applications, for instance the production of technical pure titanium, glass and glass ceramics, electrical ceramics, metal patinas, catalysts, electric conductors and chemical intermediates.
  • titanium dioxide (T1O2) is as a white powder pigment because of its brightness and very high refractive index. This means that relatively low levels of the pigment are required to achieve a white opaque coating.
  • One of the major advantages for titanium dioxide is its resistance to discolouration under ultraviolet (UV) light in exposed applications.
  • the titanium dioxide (T1O2) is used in products such as paints and coatings, including glazes and enamels, plastics, paper, inks, fibers, foods, pharmaceuticals and cosmetics. In particular, high performance grades of T1O2 are finding a growing market in the cosmetics sector and most toothpastes use T1O2.
  • UV light resistance properties helps prevent the discolouration of plastics in sunlight.
  • Sunscreens also use T1O2 as a blocker because of its high refractive index and the ability to protect the skin from UV light.
  • T1O2 is seeing growing demand in photo-catalysts due to its oxidative and hydrolysis properties. As a photo-catalyst, it may improve the efficiency of electrolytically splitting water into hydrogen and oxygen, and it may produce electricity in nanoparticle form. Applications include light-emitting diodes, liquid crystal displays (LCDs), and electrodes for plasma displays.
  • UV light Under exposure to UV light, it becomes increasingly hydrophilic and can be used for anti-fogging coatings and self-cleaning windows. It also has disinfecting properties making it suitable for applications such as medical devices, food preparation surfaces, air conditioning filters and sanitary ware surfaces.
  • T1O2 tends to lose oxygen and becomes a semiconductor.
  • the electrical resistivity of the material can be correlated to the oxygen content of the atmosphere and hence it can be used as an oxygen sensor.
  • T1O2 the major consuming industries of T1O2 are in the mature sectors in the developed world such as paints and coatings applications, paper and paperboard, and plastics. Therefore the consumption of T1O2 tends to follow general economic trends.
  • the present invention provides a process for extracting nanomaterials of titanium dioxide with 100 % purity at moderate conditions.
  • the developed novel and low-cost process does not demand high temperatures but operates at much lower temperatures of less than 200 °C to convert ilmenite (such as Sri Lankan ilmenite) to pure titanium dioxide nanomaterials such as nanorods and nanoparticles.
  • the present invention provides a closed hydrothermal system for carrying out the process, utilizing is revolving autoclave to maintain the desired pressure and temperature conditions within the closed system.
  • the process and apparatus are adapted in such a manner that the autoclave of the present invention breaks the crystalline structure of hard inorganic solids at considerably lowers temperatures.
  • the autoclave provides a closed system for carrying out the present, which may prevent chemicals from escaping to the environment.
  • the present invention provides a process which may be environmentally nonhazardous, and universally adaptable for the large-scale synthesis of the phase- specific pure titanium dioxide from natural ilmenite.
  • the process of the present invention provides a refluxing technique to remove impurities such as silica impurities.
  • the present invention provides a process and system for extracting titanium dioxide nanomaterials at moderate conditions, which is feasible, sustainable, effective, and efficient as compared to existing processes.
  • the present invention provides a process that has many advantages over the conventional processes that are currently used.
  • the process developed operates under much milder conditions than conventional process over a considerably reduced time scale and generates highly value-added nanomaterials rather than micrometer scale materials with specified dimensions of nanomaterials.
  • the improved process itself has a significant cost reduction while the materials generated also contribute many advantages as nanomaterials can be produced directly from our process without having to reduce size of micrometer size materials using either mechanical processes such as milling or using chemical processes.

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Abstract

La présente invention concerne un procédé d'extraction de nanomatériaux de dioxyde de titane à partir d'ilménite naturelle dans des conditions modérées. Le procédé comprend le prétraitement de l'ilménite pour former des particules d'ilménite. Le procédé comprend en outre la lixiviation du fer à partir des particules d'ilménite par traitement avec une solution d'acide sous des conditions hydrothermales prédéterminées dans un système rotatif fermé d'un autoclave. En outre, le procédé comprend le traitement des particules de résidu résultantes pour obtenir un produit intermédiaire. En outre, le produit est mis à réagir avec du peroxyde d'hydrogène aqueux dans un milieu alcalin à une température de 30 °C à 100 °C pendant 1 à 5 heures sous une technique de reflux pour obtenir une solution de titane. La solution est centrifugée pour obtenir un surnageant comprenant les composés de titane lixiviés. Les composés sont mélangés avec une solution de bromure d'hexadécyltriméthylammonium en concentration micellaire et d'eau-alcool à une température de 50 °C à 300 °C pendant 1 à 5 heures. Le mélange obtenu est traité, ce qui permet d'extraire les nanomatériaux de dioxyde de titane à une pureté de 100 %.
PCT/IB2020/057245 2019-08-13 2020-07-31 Procédé et système d'extraction de nanomatériaux de dioxyde de titane à partir d'ilménite naturelle Ceased WO2021028769A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113926469A (zh) * 2021-08-23 2022-01-14 浙江纳风净化技术有限公司 一种光触媒活性炭的制备方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3935094A (en) * 1974-10-10 1976-01-27 Quebec Iron And Titanium Corporation - Fer Et Titane Du Quebec, Incorporated Magnetic separation of ilmenite
CN1752016A (zh) * 2005-07-28 2006-03-29 同济大学 一种新型的纳米二氧化钛粉体制备方法
US20170050863A1 (en) * 2014-04-30 2017-02-23 Zibo Shengtai Composite Material Technology Co. Ltd. Method for Preparing Nanometer Titanium Dioxide

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3935094A (en) * 1974-10-10 1976-01-27 Quebec Iron And Titanium Corporation - Fer Et Titane Du Quebec, Incorporated Magnetic separation of ilmenite
CN1752016A (zh) * 2005-07-28 2006-03-29 同济大学 一种新型的纳米二氧化钛粉体制备方法
US20170050863A1 (en) * 2014-04-30 2017-02-23 Zibo Shengtai Composite Material Technology Co. Ltd. Method for Preparing Nanometer Titanium Dioxide

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HOSEIN LAVASANI SEYED, SARVI MEHDI NASIRI, AZIMI EBRAHIM: "Synthesis of Mesoporous Nanoparticles of TiO 2 in Anatase form from Ilmenite Concentrate", IMAT 2018 - /TH INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING AND METALLURGY, TEHERAN, IRAN, 09102018-10102018, 1 October 2018 (2018-10-01), TEHERAN, IRAN, 09102018-10102018, pages 1 - 7, XP055780406, [retrieved on 20210301] *
RAJAKARUNA THARINDU P. B., UDAWATTE CHANDANA P., CHANDRAJITH ROHANA, RAJAPAKSE R. M. GAMINI: "Nonhazardous Process for Extracting Pure Titanium Dioxide Nanorods from Geogenic Ilmenite", ACS OMEGA, ACS PUBLICATIONS, US, vol. 5, no. 26, 7 July 2020 (2020-07-07), US, pages 16176 - 16182, XP055780376, ISSN: 2470-1343, DOI: 10.1021/acsomega.0c01756 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113926469A (zh) * 2021-08-23 2022-01-14 浙江纳风净化技术有限公司 一种光触媒活性炭的制备方法
CN113926469B (zh) * 2021-08-23 2024-04-19 浙江纳风净化技术有限公司 一种光触媒活性炭的制备方法

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