Agglomeration of fine ores

Abstract

Fine ore particles are agglomerated by a process of: a. obtaining an aqueous binder solution; b. mixing the binder solution with fine ore particles to form a granulated green mix; c. drying the granulated green mix to reduce moisture content to form a dry mixture; and d. calcining the dry mixture to form dry ore agglomerates; where at least 50% by weight of the fine ore particles have a particle size below 105 µm; and where the binder solution comprises an aqueous solution of a compound selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH. Agglomerated fine ores made by the process are also envisioned. Such agglomerates maximize yield for processes, including for TiO2 production.

Description

TI0014-W001TITLE OF THE INVENTION AGGLOMERATION OF FINE ORES CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U. S. Provisional Application No. 63 / 749,735 filed January 27, 2025 and U. S. Provisional ApplicationNo. 63 / 862,863 filed August 13, 2025, the disclosures of which are incorporated herein by reference in their entirety.FIELD

[0002] The invention relates to fine ore feedstocks and a process for forming agglomerates by incorporating a binder into the fine ore. Such fine ore agglomerates maximize yield of useable product obtained from the ore and improve processibility of the feedstock.BACKGROUND

[0003] The production of titanium dioxide (TiO2) involves the utilization of titanium- bearing ores, such as ilmenite and rutile, as primary feedstock. These ores undergo a series of chemical processes to extract and purify titanium dioxide. The two predominant industrial methods for TiO2production are the sulfate process and the chloride process, where the choice of process depends on the desired quality of the final product and the specific characteristics of the ore feedstock.

[0004] In the sulfate process, the titanium-bearing ore is first digested with sulfuric acid to produce a solution of titanium sulfate. This solution is then hydrolyzed to precipitate hydrated TiO2, which is subsequently calcined to produce pure TiO2. This method is known for its ability to handle a wide range of ore qualities but generates significant amounts of acidic waste. The chloride process, on the other hand, involves the chlorination of titanium-bearing ores to produce titanium tetrachloride (TiCl4). This intermediate is then purified and oxidized to yield high-purity TiO2. The chloride process is favored for producing high-quality TiO2with fewer impurities and is generally more energy-efficient. Both processes rely on the consistent supply of high-quality ore feedstock to ensure efficient production and high-quality output.

[0005] Using fine ore feedstock in titanium dioxide production presents several challenges. One significant issue is the handling and processing of fine particles, which can lead to operational difficulties such as clogging and poor flowability in theTI0014-W001equipment. These fine particles can also cause dust generation in the surrounding areas. Additionally, the loss of fine particles during processing causes an overall yield loss. For these reasons, ore feedstocks having lower fines contents are generally preferred.SUMMARY

[0006] However, the ability to source and process diverse grades of ore provides a competitive advantage in maintaining a stable supply chain and meeting market demands. It is a goal of the invention to provide a method for using fine ore feedstocks by agglomerating the fine particles into larger particles that can be more efficiently processed.

[0007] In one aspect, the invention relates to a process for agglomerating fine ore particles comprising:a. obtaining an aqueous binder solution;b. mixing the binder solution with fine ore particles to form a granulated green mix;c. drying the granulated green mix to reduce moisture content to form a dry mixture; andd. calcining the dry mixture to form dry ore agglomerates;where at least 50% by weight of the fine ore particles have a particle size below 105 μm; and where the binder solution comprises an aqueous solution of a compound selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH. In one aspect, the binder solution comprises at most 1% by weight organic compounds, based on the solids weight of the granulated green mix. Agglomerated fine ores made by the process are also envisioned.

[0008] In another aspect, the invention relates to a composition of dry ore agglomerates comprising fine ore particles distributed within a matrix of a binder compound, where at least 50% by weight of the fine ore particles have a particle size below 105 μm; and where the binder compound is selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH. In one aspect, the matrix comprises at most 1% by weight organic compounds, based on the total weight of the dry ore agglomerates.TI0014-W001BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGURE 1 is an image of dry ore agglomerates formed in Example 28.

[0010] FIGURE 2 is an image of dry ore agglomerates formed in Comparative Example J.DETAILED DESCRIPTION

[0011] It is a goal of the invention to significantly increase the particle size distribution (PSD) of fine ore to reduce particle blow-over in the plant and minimize ore yield losses. However, PSD must not be so large that the fluidization behavior of the particles in the subsequent processes is adversely affected. Further, the process of agglomerating the fine ore feedstock must provide formation of strong agglomerates that resist breakage during transportation and handling, including the handling by feeding the agglomerated ore into a chlorinator or other processes. Another benefit of fine ore agglomeration is reduced dustiness. Dustiness is especially problematic for transportation and handling of fine ores from both TiO2process yield and for environmental, health, and safety perspectives.

[0012] In one aspect, the invention relates to a process for agglomerating fine ore particles comprising:a. obtaining an aqueous binder solution;b. mixing the binder solution with fine ore particles to form a granulated green mix;c. drying the granulated green mix to reduce moisture content to form a dry mixture; andd. calcining the dry mixture to form dry ore agglomerates;where at least 50% by weight of the fine ore particles have a particle size below 105 μm; and where the binder solution comprises an aqueous solution of a compound selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH. Agglomerated fine ores made by the process are also envisioned.

[0013] In another aspect, the invention relates to a composition of dry ore agglomerates comprising fine ore particles distributed within a matrix of a binder compound, where at least 50% by weight of the fine ore particles have a particle size below 105 μm; and where the binder compound is selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH.TI0014-W001

[0014] In another aspect, the invention relates to a composition of dry ore agglomerates comprising fine ore particles adhered at an interface between particles with a matrix of a binder compound, where at least 50% by weight of the fine ore particles have a particle size below 105 pm; and where the binder compound is selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH.

[0015] In another aspect, the invention relates to a composition of granulated green mix comprising fine ore particles distributed within a matrix of a binder compound, where at least 50% by weight of the fine ore particles have a particle size below 105 pm; and where the binder compound is selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH.

[0016] It is desirable to be able to agglomerate all types of ore feedstocks bearing fine particles, including both rutile and ilmenite when using Ti-bearing ore feedstocks. Slagging fines or leucoxene may also be encompassed, for example. Agglomerating the fine ore particles would yield particles that can be more efficiently processed in further reaction vessels. In one aspect, the fine ore particles are Ti- bearing fine ore particles. In one aspect, the fine ore particles comprise at least about 20% by weight TiC; in another aspect, at least about 30% by weight TiC; in another aspect, at least about 40% by weight TiC, in another aspect, at least about 50% by weight TiC>2, all based on the total weight of the fine ore feedstock. In one aspect, the fine ore particles comprise at least 20% by weight Tit; in another aspect, at least 30% by weight TiCh; in another aspect, at least 40% by weight TiG>2, in another aspect, at least 50% by weight TiC>2, all based on the total weight of the fine ore feedstock. In one aspect, the fine ore particles comprise at most about 98% by weight TiOs; in another aspect, at most about 95% by weight TiC; in another aspect, at most about 90% by weight TiC; in another aspect, at most about 80% by weight TiC; in another aspect, at most about 75% by weight TiCh; in another aspect, at most about 70% by weight TiO2, all based on the total weight of the fine ore feedstock. In one aspect, the fine ore particles comprise at most 98% by weight TiC; in another aspect, at most 95% by weight TiCh; in another aspect, at most 90% by weight TiC>2; in another aspect, at most 80% by weight TiC; in another aspect, at most 75% by weight TiC; in another aspect, at most 70% by weight TiC>2, all based on the total weight of the fine ore feedstock. In one aspect, the fine ore particles comprise at least 20% by weight TiOs; in another aspect, at least 30% by weightTI0014-W001TiC; in another aspect, at least 40% by weight TiC, in another aspect, at least 50% by weight TiO2, all based on the total weight of the fine ore feedstock. In one aspect, the fine ore particles comprise at least 20% by weight TiC; in another aspect, at least 30% by weight Tit; in another aspect, at least 40% by weight TiCh, in another aspect, at least 50% by weight TiO2, all based on the total weight of the fine ore feedstock. In one aspect, the fine ore particles comprise at most about 98% by weight TiC; in another aspect, at most 95% by weight TiO2; in another aspect, at most 90% by weight TiCh; in another aspect, at most 80% by weight Tit; in another aspect, at most 75% by weight TiC; in another aspect, at most 70% by weight TiC, all based on the total weight of the fine ore feedstock. In one aspect, the fine ore particles comprise at most 98% by weight TiC; in another aspect, at most 95% by weight TiCh; in another aspect, at most 90% by weight TiC; in another aspect, at most 80% by weight TiC; in another aspect, at most 75% by weight TiC; in another aspect, at most 70% by weight TiC>2, all based on the total weight of the fine ore feedstock.

[0017] The fine ore particle content of an ore feedstock, defined as % by weight of particles having a particle size < 105 pm, is generally low, in the range of 10-20%. Fine ore feedstocks are defined for this work as ores or ore fractions with d50 <90 pm and / or fine tail > 50% by weight. In one aspect, at least 60% by weight of the fine ore particles have a particle size below 105 pm; in another aspect, at least 70% by weight of the fine ore particles have a particle size below 105 pm; and in another aspect, at least 80% by weight of the fine ore particles have a particle size below 105 pm. The fine ore particles may represent a feedstock as-is, without further processing, or the fine ore particles may result from separating a main feedstock by particle size and collecting the fine ore particles.

[0018] Generally, the PSD of ores that are used in the chloride process for forming TiCl4, a precursor of commercial TiO2, have a mean particle diameter (d50) in range of 90-400 pm. The dry ore agglomerates, on the other hand, may have a d50 of at least about 100 μm; in another aspect, at least about 150 μm; in another aspect, at least about 200 μm; in another aspect, at least about 250 μm; in another aspect, at least about 300 μm; in another aspect, at least about 350 μm; and in another aspect, at least about 400 μm. In some cases, the dry ore agglomerates may have a d50 of at least 100 μm; in another aspect, at least 150 μm; in another aspect, at least 200 μm; in another aspect, at least 250 μm; in another aspect, at least 300 μm; inTI0014-W001another aspect, at least 350 μm; and in another aspect, at least 400 μm. In some cases, particle distributions that are too large may also present processing issues. In one aspect, the dry ore agglomerates may have a d50 of at most about 900 μm; in another aspect, at most about 850 μm; in another aspect, at most about 800 μm; in another aspect, at most about 750 μm; and in another aspect, at most about 700 μm. In one aspect, the dry ore agglomerates may have a d50 of at most 900 μm; in another aspect, at most 850 μm; in another aspect, at most 800 μm; in another aspect, at most 750 μm; and in another aspect, at most 700 μm.

[0019] Another way to characterize PSD is by calculating the fraction of sample having particle size above 105 μm. In one aspect, at least 50% by weight of the dry ore agglomerates have a particle size above 105 μm; in another aspect, at least 60% by weight of the dry ore agglomerates have a particle size above 105 μm; in another aspect, at least 65% by weight of the dry ore agglomerates have a particle size above 105 μm; in another aspect, at least 70% by weight of the dry ore agglomerates have a particle size above 105 μm; in another aspect, at least 75% by weight of the dry ore agglomerates have a particle size above 105 μm; in another aspect, at least 80% by weight of the dry ore agglomerates have a particle size above 105 μm; in another aspect, at least 85% by weight of the dry ore agglomerates have a particle size above 105 μm; and in another aspect, at least 90% by weight of the dry ore agglomerates have a particle size above 105 μm.

[0020] The fine ore particles are mixed with a binder solution to form a granulated green mix. The binder solution is an aqueous binder solution that comprises a binder compound and water, where the binder compound is sodium silicate or mixtures of sodium silicate with either NaOH or KOH. The binder solution may be obtained in any suitable manner. In one aspect, the binder solution is formed, for example, by obtaining a concentrated aqueous solution of binder compound in water and further diluting with water. Alternatively, the binder compound may be a solid that is dissolved in water at a desired solids content to form a binder solution, or purchased at the desired solids content. In one aspect, the binder solution is liquid.

[0021] For example, sodium silicate may be used as the binder compound.Sodium silicate solution has been identified as an effective fine ore binder which is relatively innocuous in the chlorination process. Sodium silicate may be purchased as an aqueous solution having a solids content of about 30% to about 50% by weight, based on the total weight of the binder solution. One such product is Grade 9TI0014-W001from WR Grace (Columbia, MD) with about 37% total solids (28% SiC>2 and 9% Na2O) and 63% water. The binder solution may be diluted to a lower solids content so the binder solution may coat the fine ore particles more readily. In one aspect, the binder solution contacting the fine ore particles has a solids content of about 10 to about 40% by weight; in another aspect, about 12 to about 35% by weight; in another aspect, about 15 to about 30% by weight; and in another aspect, about 20 to about 30% by weight, all based on the total weight of the binder solution. In one aspect, the binder solution contacting the fine ore particles has a solids content of 10 to 40% by weight; in another aspect, 12 to 35% by weight; in another aspect, 15 to 30% by weight; and in another aspect, 20 to 30% by weight, all based on the total weight of the binder solution.

[0022] The binder compound has a molar ratio of SiOs: NasO of about 0.5:1 to about 3.75:1; and in another aspect, the binder compound has a molar ratio of SiO?: Na2< D of about 2:1 to about 3:1. In one aspect, the binder compound has a molar ratio of SiO2: Na2O of 0.5:1 to 3.75:1; and in another aspect, the binder compound has a molar ratio of SiO2: Na2O of 2:1 to 3:1. Such materials may be purchased as is or modified to affect the ratio. For example, aqueous solutions with about 30% total solids (20% SiO2and 10% Na2O; about 2:1 molar ratio) could be produced by addition of 20% NaOH solution to a sodium silicate solution containing the typical 3:1 molar ratio. Solutions containing a SiO2:Na2O ratio of about 2:1 may also be commercially available.

[0023] The binder solution may also contain TiC>2 waste water as part of the total water content. For example, the TiC>2 waste water may be used as all or part of the water in a dilution step. The TiC waste water may be sourced from any part of the TiO2 production process, for example, waste from washing the TiCh particles or waste from filtration. The waste water likely carries residual TiCh particles. In one aspect, the binder solution has up to 5% by weight TiC>2 particles, based on the total weight of the binder solution. The TiC>2 waste water may also contain dissolved salts or processing compounds, for example NaCI and / or HCI. Such salts or compounds may be present in an amount of up to 5% by weight, based on the total weight of the binder solution. In one aspect, the binder solution further comprises NaOH, NaCl, HCl, TiO2particles, or mixtures thereof.

[0024] Organic compounds may lead to processing problems in the reactor after the dry ore agglomerates are produced, such as easily broken agglomerates or fastTI0014-W001reaction in the process which causes regeneration of fines and yield loss. In one aspect, the binder solution comprises at most 1% by weight organic compounds; in another aspect, at most 0.9% by weight organic compounds; and in another aspect, at most 0.8% by weight organic compounds, all based on the total weight of the binder solution. Further, in one aspect, the granulated green mix comprises at most 1% by weight organic compounds; in another aspect, at most 0.9% by weight organic compounds; and in another aspect, at most 0.8% by weight organic compounds, all based on the total weight of the granulated green mix. In another aspect, it is the intention of the invention that no organic compounds are added during the production of the dry ore agglomerates.

[0025] The granulated green mix comprises fine ore particles, binder compound, and water. The granulated green mix comprises about 2% to about 7%; in another aspect, about 2.5% to about 6% by weight; and in another aspect, about 2.8% to about 5.7% by weight of a binder compound, all based on the total weight of the granulated green mix. The granulated green mix comprises about 3% to about 15% by weight water; in another aspect, about 5% to about 15% by weight water; in another aspect, about 8 to about 14% by weight water; and in another aspect, about 9 to about 12.5% by weight water, all based on the total weight of the granulated green mix. The balance of the granulated green mix is the content of the fine ore particles. For example, the granulated green mix comprises about 78% to about 95% by weight; in another aspect 78% to about 93% by weight; in another aspect, about 80% to about 89.5%; and in another aspect, about 81.8% to about 88.2% by weight fine ore particles, all based on the total weight of the granulated green mix. In a similar aspect, the dry ore agglomerates may comprise the binder compound in an amount of about 2% to about 7%; in another aspect, about 2.5% to about 6% by weight; and in another aspect, about 2.8% to about 5.7% by weight, all based on the total weight of the dry ore agglomerates. After calcining, the binder compound may contain amounts of silicon dioxide and / or sodium carbonate in addition to sodium silicate as products of the heating process.

[0026] The granulated green mix is formed by mixing the binder solution with fine ore particles and can be performed by any suitable method. For example, shear may be applied by mixing by hand, in a stand mixer, pin mixer, fluidized bed mixer, mechanical mixer, aeromechanical mixer, or intensive planetary mixer such as an Eirich mixer. Any type of mixer marketed as high shear or intensive mixers may beTI0014-W001used to apply shear onto the components during mixing. In one aspect, shear is applied to the binder solution mixture during step b or to the granulated green mixture prior to drying step c. In one aspect, the shear is applied at a shear rate of at least about 50 / s; in another aspect, at least about 75 / s; in another aspect, at least about 100 / s; in another aspect, at least about 150 / s; in another aspect, at least about 200 / s; in another aspect, at least about 250 / s; in another aspect, at least about 300 / s; in another aspect, at least about 350 / s; in another aspect, at least about 400 / s; in another aspect, at least about 450 / s; and in another aspect, at least about 500 / s. Shear rate can be calculated based on the rotational speed of the rotor and the gap between the rotor and sidewall of the vessel using the equations below:circumferential speed of rotorShear rate = gap between rotor and vessel wallCircumferential speed of rotor = 2πrrotor× revolutions per minute × 1 minute / 60 seconds60 seconds

[0027] In one aspect, additional water is added at step b to the binder solution and fine ore particles to form a granulated green mix of desired solids content. In another aspect, no additional water is added to the binder solution and fine ore particles at step b when forming the granulated green mix. Upon mixing of the binder solution and the ore, the green mixture is granulated into agglomerates of the fine particles. Granulation is the process of forming grains or granules from a powdery or solid substance and producing a granular material. This step may alternatively be referred to as “pan pelletization” or “spheroidization”. With a high intensity solids mixer, such as a commercially available Eirich Mixer (Gurnee, IL), granulation occurs as the fine ore particles agglomerate together with the binder solution to form a clumpy, moist sand with larger, semi-permanent agglomerates.

[0028] On the laboratory scale, granulation can also be achieved by sieving the green mix through a 4- or 6-mesh sieve into a pan and subsequently moving the pan rapidly in a circular motion to form the larger, semi-permanent ball-shaped agglomerates.

[0029] After the granulated green mix is formed, it is dried in step c to reduce the moisture content. Drying of the granulated green mix can be performed, for example for 5 hours, at a temperature that will remove water, for example at least 100 °C or 110 °C, in a convection air drying oven or a commercial dryer. This step significantlyTI0014-W001reduces the moisture content of the mixture and forms relatively hard agglomerates as needed for further processing in the laboratory. Shorter times are required for drying at an industrial scale.

[0030] In one aspect, the process further comprises the step c1 of crushing the dry mixture to form a crushed dry mixture prior to performing calcining step d. In one aspect, the process further comprises the step c2 of sieving the dry mixture or crushed dry mixture to remove particles above a desired particle size to form a sieved mixture prior to performing calcining step d. For example, the dried agglomerates can be crushed and then sieved through a 16-mesh sieve after drying, which allows only dried agglomerated particles with a size of approximately <1200 pm to pass through into the calcining step. The purpose of these crushing and sieving steps is to reduce and remove large, oversized particles so that formation of large, oversized calcined agglomerates can be avoided. If the large, oversized agglomerates were to be calcined, they would be difficult to grind without a very energy intensive process step, so it is desirable to prevent their formation.

[0031] Alternatively, other means of drying the granulated green mix can be employed instead of convection air oven drying to avoid formation of oversized particles altogether. For example, a fluid-bed dryer could mitigate formation of hard oversized agglomerated particles by dispersing the granulated green mix into flowing hot air, thus minimizing formation of larger-sized hardened agglomerates. Avoiding the crushing and sieving steps c1 and c2 would provide a simpler and more efficient process.

[0032] The calcining step d can be performed by any suitable means of heating at high temperature. Calcining, as opposed to sintering, adheres the particles together with the binder while allowing the dry ore particles to remain as distinct or discrete particles. This forms a bond or adhesion between particles at an interface, where the interface is composed of binder or matrix material. In one aspect, the calcining step is performed without sintering, and / or the binder of the dry ore agglomerates is calcined but not sintered. The calcining step may be performed, for example, in a furnace, or in a fluidized bed combination dryer. In an industrial process, the calcining step may be performed in a fluidized bed combination dryer, in which excess heat from the calciner is used in the dryer positioned above the calciner. Calcining the sized and dried agglomerates ensures formation of hard agglomerated ore particles which will resist breakage during transportation and handling.TI0014-W001

[0033] In one aspect, the calcining step d is performed at a temperature of at most about 1000 °C; in another aspect, at most about 975 °C; in another aspect, at most about 950 °C; in another aspect, at most about 925 °C; and in another aspect, at most about 910 °C. In one aspect, the calcining step d is performed at a temperature of at least about 500 °C; in another aspect, at least about 550 °C; in another aspect, at least about 600 °C; in another aspect, at least about 650 °C; in another aspect, at least about 700 °C; in another aspect, at least about 750 °C; in another aspect, at least about 800 °C; and in another aspect, at least about 850 °C.

[0034] The hold time can be any time that suitably calcines the material and can include periods of time where the system is heating up or cooling down. In another aspect, the calcining step is performed at a consistent temperature throughout the time period. The calcining step d may be performed for at least 3 minutes; in another aspect, at least 5 minutes; in another aspect, at least 10 minutes; in another aspect, at least 15 minutes; in another aspect, at least 20 minutes; in another aspect, at least 25 minutes; in another aspect, at least 30 minutes; in another aspect, at least 45 minutes; in another aspect, at least 60 minutes; in another aspect, at least 90 minutes; and in another aspect, at least 120 minutes. The maximum time for calcining is typically not bound, except that efficacy of the calcining step may stop improving at some point.

[0035] The ability of the dry ore agglomerates to resist breakage can be demonstrated by the attrition resistance index (ARI) of the particles. In one aspect, the dry ore agglomerates have an ARI of at least about 50%; in another aspect, at least about 60%; in another aspect, at least about 65%; in another aspect, at least about 70%; in another aspect, at least about 75%; in another aspect, at least about 80%; in another aspect, at least about 85%; in another aspect, at least about 90%; and in another aspect, at least about 95%.

[0036] The dry ore agglomerates can be used as a feedstock in further chemical reactions to make use of fine ore materials that may otherwise be disposed of as waste. For example, dry ore agglomerates from Ti-bearing ores can be used in the sulfate process or the chloride process. In one aspect, the invention is further drawn to a process for making TiO2comprising reacting the dry ore agglomerates with chlorine or sulfuric acid to produce TiC>2 precursors, and reacting the TiC>2 precursors to form TiO2. Specifically for the chlorination process, the invention is drawn to aTI0014-W001process for making TiC>2 comprising reacting the dry ore agglomerates with chlorine to produce TiCk, and oxidizing the TiCk precursors to form TiO2.EXAMPLES TEST METHODSAttrition Resistance (ARI)

[0037] ARI was conducted by milling the dry ore agglomerates with 301 / 8” stainless steel (SS) balls, 10 1 / 8” SS back ferrules, and 10! ” SS back ferrule. First, a sample of the dry ore agglomerates was screened at 200 mesh to collect 15.0 g of material >105 pm. The collected material was combined with the SS balls and back ferrules described above and milled for 5.0 minutes at 100 rpm in a pint-sized square plastic bottle. The milled material was then collected, and the SS balls and back ferrules were removed. The weight of dry ore agglomerates >105 pm after milling was then determined. The ARI was the calculated ratio of the weight of dry ore agglomerates >105 pm collected after mixing compared to the original starting weight of material >105 pm. High ARI values indicate strong agglomerates that resist breakage during transportation and handling.Particle Size Distribution (PSD)

[0038] The PSD of the fine and agglomerated fine ore samples in this work was determined using a stacked screen methodology. A stack of 10 screens (20, 30, 40, 50, 70, 100, 140, 200, 270, and 325 mesh), 3-inch diameter, with largest sieve size on top to smallest sieve size on the bottom, with a collection pan, was prepared, and a 35.0 g weighed sample was added to the top screen. After shaking the stack of sieves with the sample for 10 minutes (at a setting of 10 minutes with a 1 -minute pause after each minute of shaking) on a Gilson sieve shaker, the weight of sample on each of the individual screens was obtained. These weights and calculated weight fractions were used to determine the percentage of sample in each size fraction and other summary PSD parameters, including the d50 (i.e., the mean particle size) and the fine tail (i.e., the % by weight <105 pm). The fine tail corresponds to the total weight % of sample captured on the 140, 200, 270, 325 mesh sieves, and the collection pan.TI0014-W001SAMPLES AND PERFORMANCEComparative Example A-C

[0039] Ore samples from three different mining locations were tested for particle size distribution according to the Test Methods above. These materials were all ilmenite ores, with % by weight of TiO263.20% (Comparative Example A), 59.49% (Comparative Example B), and 66.09% (Comparative Example C).Examples 1-5

[0040] A 30-g batch sample of ore from Comparative Example A was mixed in a 250 mL plastic bottle with diluted Grade 9 (3:1 SiO2: Na2O; 37% by weight solids) sodium silicate binder solution, using water to further dilute the binder solution and achieve the desired solids and total water amounts. In the examples, the SiC: Na2O ratio indicates a molar ratio of SiC: Na2< D. The binder and water amounts were varied according to Table 1. After addition of the binder solution to the mixture was completed, it was shaken by hand intensively for 2 minutes. The mixture was then sieved at 6 mesh, with tapping and swirling of the sieve and receiving pan to get the material to pass through and encourage spheroidization of the agglomerates. The green mix was then dried at 110 °C for 2 hours, crushed, and sieved at 16 mesh. The resulting material was placed in a ceramic dish, placed in a furnace, and heated to 900 °C using a pre-programmed heat-up rate of 20 °C / min. Once this temperature was achieved, the furnace was held at 900 °C for 2 hours and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.Examples 6 and 7

[0041] A 300-g batch sample of ore from Comparative Example A was mixed in a stand mixer at speed 1 (shear rate 85 / s) with diluted Grade 9 (3:1 SiO2: Na2O; 37% solids) sodium silicate binder solution, using water to further dilute the binder solution and achieve the desired solids and total water amounts. The binder and water amounts were varied according to Table 1. The binder solution was added slowly with continuous mixing over the course of 5 minutes, and mixing was continued for 1 minute after the addition was complete. The mixture was then sieved at 6 mesh, with tapping and swirling of the sieve and receiving pan to get the material to pass through and encourage spheroidization of the agglomerates. The green mix was then dried at 110 °C for 5 hours, crushed, and sieved at 16 mesh. The resultingTI0014-W001material was placed in a ceramic dish and placed in a furnace and heated to 900 °C using a pre-programmed heat-up rate of 20 °C / min. Once this temperature was achieved, the furnace was held at 900 °C for 2 hours and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.TABLE 1. COMPOSITION AND PERFORMANCE FOR COMPARATIVE EXAMPLE A AND EXAMPLES 1-7Example Binder (% Water (% Ore Particles ARI (%) d50 (pm) % >105 by weight) by weight) (% by weight) pm A 100 97 36.1 1 2.0 12.1 85.9 33 127 59.5 2 2.6 12.1 85.3 40 204 69.1 3 3.0 12.1 84.9 57 684 88.6 4 3.7 12.2 84.1 76 >850 94.7 5 5.6 12.2 82.2 97 >850 99.7 6 3.0 9.0 88.0 87 471 91.67 3.7 9.0 87.3 96 703 98.5

[0042] Overall, the data show the impact of both increasing % binder and the effect of changing % water, all of which show improved PSD compared with the starting material. Examples 1-5 show increased ARI from 33 up to 97% as the % binder was increased from 2.0-5.6% by weight. Performance of ARI >90% was achieved with 5.6% by weight binder. Examples 6 and 7 show that a decrease in water content enabled increased ARI at a lower binder content. Furthermore, increasing % binder also impacted the PSD. Increased % binder enabled both increased d50 and reduced fine tail content, as seen by % >105 pm. The data showed increased d50 from 97 pm (Comparative Example A) to 684 pm at 3.0% by weight binder, and further increased with up to 5.6% by weight binder. More optimal d50 was also achieved at lower binder contents by decreasing the amount of water in the composition.Example 8-9

[0043] A 30-g batch sample of ore from Comparative Example B was mixed in a 250-mL plastic bottle with diluted Grade 9 (3:1 SiO2: Na2O; 37% solids) sodium silicate binder solution, using water to further dilute the binder solution and achieve the desired solids and total water amounts. The binder and water amounts were varied according to Table 2. The binder solution was added in 1-mL increments, with vigorous shaking by hand after each increment. After addition of the binder solutionTI0014-W001to the mixture was completed, it was shaken by hand intensively for 1 min. The mixture was then sieved at 6 mesh, with tapping and swirling of the sieve and receiving pan to get the material to pass through and encourage spheroidization of the agglomerates. The green mix was then dried at 110 °C for 2 hours, crushed, and sieved at 16 mesh. The resulting material was placed in a ceramic dish, placed in a furnace, and heated to 900 °C using a pre-programmed heat-up rate of 20 °C / min. Once this temperature was achieved, the furnace was held at 900 °C for 2 hours and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.Examples 10-12

[0044] A 300-g batch sample of ore from Comparative Example C was mixed in a stand mixer at speed 1 (shear rate 85 / s) with diluted Grade 9 (3:1 SiO2: Na2O; 37% solids) sodium silicate binder solution, using water to further dilute the binder solution and achieve the desired solids and total water amounts. The binder and water amounts were varied according to Table 2. The binder solution was added slowly with continuous mixing over the course of 5 minutes and mixing was continued for 1 minute after addition was complete. The mixture was then sieved at 6 mesh, with tapping and swirling of the sieve and receiving pan to get the material to pass through and encourage spheroidization of the agglomerates. The green mix was then dried at 110 °C for 5 hours, crushed, and sieved at 16 mesh. The resulting material was placed in a ceramic dish, placed in a furnace, and heated to 900 °C using a pre-programmed heat-up rate of 20 °C / min. Once this temperature was achieved the furnace was held at 900 °C for 2 hours and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.TABLE 2. COMPOSITION AND PERFORMANCE OF COMPARATIVE EXAMPLE B-C AND EXAMPLES 8-12Example Binder (% Water (% Ore Particles ARI (%) d50 (pm) % >105 by weight) by weight) (% by weight) pm B 100 87 21.7 8 3.7 9.0 87.3 88 531 96.1 9 5.6 9.0 85.4 93 662 95.6 C 100 62 0.5 10 3.7 9.0 87.3 90 335 83.5 11 4.6 9.0 86.4 97 355 96.212 5.6 9.0 85.4 97 418 99.3TI0014-W001

[0045] In the examples above, the ARI and PSD increased with increasing % binder. With both ores, a high ARI% was achieved. It can be seen that different ores require different amount of binder to achieve the highest ARI, and different starting ores yield different d50 values.Examples 13-15

[0046] A 900-g batch sample of ore from Comparative Example A was mixed in a stand mixer at speed 1 (shear rate 85 / s) with diluted Grade 9 (3:1 SiO2: Na2O; 37% solids) sodium silicate binder solution at a composition of 3.7% by weight sodium silicate, 9.0% by weight total water, and 87.3% by weight ore, using water to further dilute the binder solution and achieve the desired solids and total water amounts. The binder solution was added slowly with continuous mixing over the course of 5 minutes and mixing was continued for 1 minute after addition was complete. The mixture was then sieved at 6 mesh, with tapping and swirling of the sieve and receiving pan to get the material to pass through and encourage spheroidization of the agglomerates. The green mix was then dried at 110° °C for 5 hours, crushed, and sieved at 16 mesh. At this point, the material was split into 3 batches of about 300g. Each batch was sub-divided into 100-g aliquots, which were placed into a ceramic dish for calcining. In these experiments, the furnace was heated to a maximum temperature of either 500, 700, or 900 °C using a pre-programmed heatup rate of 20 °C / min. Once the target temperature was achieved the furnace was held at that temperature for 2 hours and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.

[0047] The data reported in Table 3 below are averages for three separate ARI and PSD tests on the aliquots calcined at each temperature.TABLE 3. COMPOSITION AND PERFORMANCE OF EXAMPLES 13-15 Example Calcine Temp (°C) ARI (%) d50 (pm) % >105 pm13 500 66 303 76.414 700 77 396 85.015 900 89 327 85.5

[0048] The data in Table 3 clearly show that calcining at a higher maximum temperature was more effective at achieving a high ARI. The average ARI result at 900 °C was significantly improved compared to 700 °C calcining. The PSD results forTI0014-W001this group of samples also showed improved d50 and % >105 pm compared with Comparative Example A.Examples 16-23

[0049] A 5-kg batch sample of ore from Comparative Example A was mixed in an Eirich mixer at a composition of 3.7% by weight (3:1 SiO2: Na2O; 37% solids) sodium silicate, 9.0% by weight total water, and 87.3% by weight ore, using water to further dilute the binder solution and achieve the desired solids and total water amounts. The mixer was started at low speed for 10 s (shear rate 254 / s), increased to high speed for 120 s (shear rate 508 / s), and then set back at low speed for 60 s. The mixture was dried, crushed, and sieved at 16 mesh. The resulting material was split into 8 different aliquots and calcined at a maximum of 900 or 1000 °C for a period of time as shown in Table 4. The samples were calcined by inserting a quartz dish containing the sieved agglomerates into a preheated calciner.TABLE 4. COMPOSITION AND PERFORMANCE OF EXAMPLES 16-23 Example Calcine Calcine time ARI (%) d50 (pm) % >105 pm Temp (°C) (min)16 900 5 88 362 89.317 900 15 90 342 89.018 900 30 90 312 88.719 900 120 91 530 93.520 1000 5 91 406 92.121 1000 15 93 513 92.122 1000 30 90 283 84.523 1000 120 84 431 89.5

[0050] The data in Table 4 show a slightly higher ARI was observed at 1000 °C compared with 900 °C when the calcination was done for the two shorter residence times (i.e., 5 and 15 minutes). However, for longer residence times, there was no advantage for the higher temperature at 30 minutes or longer. Calcining at 1000 °C for 120 mins showed significantly lower ARI compared to calcining at 900 °C for 120 minutes. In other words, heating to a maximum temperature of 1000 °C for short residences times was observed to slightly enhance the ARI but prolonged heating at this temperature compared to 900 °C was detrimental to ARI. The PSD results for this group of samples also showed improved d50 and % >105 pm compared with Comparative Example A.TI0014-W001Example 24

[0051] A 750-g batch sample of ore from Comparative Example C was mixed in a stand mixer at speed 1 (shear rate 85 / s) with diluted Grade 9 (3:1 SiO2: Na2O; 37% solids) sodium silicate binder solution, using water to further dilute the binder solution, to achieve a total composition of 3.7% by weight binder, 9.0% by weight total water, and 87.3% by weight ore. The binder solution was added slowly with continuous mixing over the course of 5 minutes and mixing was continued for 1 minute after addition was complete. The mixture was then sieved at 6 mesh, with tapping and swirling of the sieve and receiving pan to get the material to pass through and encourage spheroidization of the agglomerates. The green mix was then dried at 110 °C for 5 hours, crushed, and sieved at 16 mesh. The resulting material was placed in a ceramic dish, placed in a furnace, and heated to 900 °C using a pre-programmed heat-up rate of 20 °C / min. Once this temperature was achieved, the furnace was held at 900 °C for 2 hours and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.Example 25

[0052] A 5-kg batch sample of ore from Comparative Example A was mixed in an Eirich mixer at a composition of 3.7% by weight (3:1 SiO2: Na2O) sodium silicate, 9.0% by weight total water, and 87.3% by weight ore by starting with 37% solids solution and using water to further dilute the binder solution and achieve the desired solids and total water amounts. The mixer was started at low speed for 10 s (shear rate 254 / s), increased to high speed for 120 s (shear rate 508 / s), and then set back at low speed for 60 s. A 100-g portion of the mixture was transferred into a fluidized bed furnace preheated to 900 °C with a mixture of gas (4L Ar and 1 L air) flowing at a calculated superficial velocity of 0.2 ft / sec. After 30 minutes, the furnace was turned off and opened to allow rapid cooling. The calcined solids were recovered after the furnace had cooled to room temperature.Example 26

[0053] A 2:1 SiO2:Na2O solution was made by mixing a 3:1 SiO2:Na2O sodium silicate solution (37% by weight solids) with aqueous NaOH (20% by weight solids) in an amount to achieve the 2:1 ratio. A 5-kg batch sample of ore from Comparative Example A was mixed in an Eirich mixer at a composition of 2.3% by weight (2:1 SiO2: Na2O) sodium silicate, 9.0% by weight total water, and 88.7% by weight ore,TI0014-W001using water to further dilute the binder solution and achieve the desired solids and total water amounts. The mixer was started at low speed for 10 s (shear rate 254 / s), increased to high speed for 120 s (shear rate 508 / s), and then set back at low speed for 60 s. A 100-g portion of the mixture was transferred into a fluidized bed furnace heated to 900 °C with a mixture of gas (4L Ar and 1 L air) flowing at a calculated superficial velocity of 0.2 ft / sec. After 30 minutes, the furnace was turned off and allowed to cool to room temperature. The calcined solids were recovered after the furnace had cooled to room temperature.TABLE 5. COMPOSITION AND PERFORMANCE OF EXAMPLES 24-26 Example Calcine Calcine time ARI (%) d50 (pm) % >105 pm Temp (°C) (min)24 900 120 96 703 98.525 900 30 96 615 95.226 900 30 93 497 88.1

[0054] These samples showed high ARI and PSD, indicating variations of the process that could be used to achieve high performance targets.Comparative Examples D-F

[0055] Commercially available colloidal silica solutions of Ludox® SM (30% by weight solids, available from W. R. Grace & Co., Columbia, MD) were used as the binder. A 30-g batch sample of ore from Comparative Example A was mixed in a 250-mL plastic bottle with diluted binder solution. The binder, total wt.% water, and ore amounts are described in Table 6. The binder solution was added in 1-mL increments, with vigorous shaking by hand after each increment. After addition of the binder solution to the mixture was completed, the mixture was shaken by hand intensively for 1 min. The mixture was then sieved at 6 mesh, with tapping and swirling of the sieve and receiving pan to get the material to pass through the and encourage spheroidization of the agglomerates. The green mix was then dried at 110 °C for 2 hours, crushed, and sieved at 16 mesh. The resulting material was placed in a ceramic dish, placed in a furnace, and heated to 900 °C using a preprogrammed heat-up rate of 20 °C / min. Once this temperature was achieved, the furnace was held at 900 °C for 2 hours and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.TI0014-W001Comparative Examples G-I

[0056] Comparative Example D was repeated, except Ludox® HS-40 (40% by weight solids, available from W. R. Grace & Co., Columbia, MD) was used in place of Ludox® SM, according to the amounts in Table 6.TABLE 6. COMPOSITION AND PERFORMANCE FOR COMPARATIVE EXAMPLES D-IExample Binder (% Water (% Ore Particles ARI (%) d50 (pm) % >105 by weight) by weight) (% by weight) pm D 1.6 9.0 89.4 33 107 50.4 E 2.4 9.0 88.6 35 121 59.4 F 3.0 9.0 88.0 34 136 64.8 G 2.1 9.0 88.9 31 128 59.8 H 3.2 9.0 87.8 34 131 60.9I 4.0 9.0 87.0 39 126 59.9

[0057] In the examples above, the ARI and PSD were well below the target range. With increasing silica concentration using Ludox® SM, there was no significant change in performance. With Ludox® HS-40, there was some evidence for improved ARI with increasing % binder, but high ARI was not achieved. It can be seen that the use of silica sols as binders was much less effective than use of sodium silicate.Examples 27-28 and Comparative Example J

[0058] A 2:1 SiO2:Na2O solution was made by mixing a 3:1 SiO2:Na2O sodium silicate solution (37% by weight solids) with aqueous NaOH (20% by weight solids) in an amount to achieve the 2:1 ratio. A 10-kg batch sample of ore from Comparative Example A was mixed in an Eirich mixer at a composition of 2.3% by weight (2:1 SiO2: Na2O) sodium silicate, 9.0% by weight total water, and 88.7% by weight ore, using water to further dilute the binder solution and achieve the desired solids and total water amounts. The mixer was started at low speed for 10 seconds (shear rate 254 / seconds), and the binder solution was added over the course of 1 minute. The rotor speed was increased to high speed for 120 seconds (shear rate 508 / seconds), and then mixing was stopped. A 1 -kg portion of the mixture dried at 110 °C for 5 hours and then sieved at 16 mesh. Samples containing the sieved agglomerates from the dried portion were heat-treated at the temperatures and time variations listed below in a ceramic dish inserted into a preheated furnace.

[0059] As shown in Table 7, these samples also showed high ARI and PSD, indicating variations of time and temperature in the firing process that could be usedTI0014-W001to achieve performance targets. The higher temperature of 1400 °C provides desired performance at the expense of additional heat energy. A calculation shows that heating the mixture at 1400 °C (250 MMBTU / hour) requires as much as 4.17x the burner output when compared with heating the mixture to 900 °C (60 MMBTU / hour). However, Examples 27 and 28 indicate acceptable or similar performance at much lower energy consumption. The images of Example 28 and Comparative Example J from high resolution optical microscopy (FIGURES 1 and 2) indicate the desired agglomerated ore grains at 900 °C and early-stage sintering of the grains at 1400 °C calcination.Example 29

[0060] A 2:1 SiO2: Na2O solution was made by mixing a 3:1 SiO2: Na2O sodium silicate solution (37% by weight solids) with aqueous NaOH (20% by weight solids) in an amount to achieve the 2:1 ratio. A 75-kg batch sample of ore from Comparative Example A was mixed in an Eirich mixer at a composition of 2.3% by weight (2:1 SiO2: Na2O) sodium silicate, 4.7% by weight total water, and 93.0% by weight ore. The mixer was started at low speed for 60 seconds (shear rate 103 / seconds) and the binder solution was added over the course of 1 minute. The rotor speed was held at low speed for 60 seconds and then increased to high speed for 120 seconds (shear rate 137 / seconds) and then the mixture was discharged in 30 seconds. No additional water was used to dilute the mixture. A portion of the mixture was dried at 150 °C for 2 hours and then sieved at 16 mesh. The resulting material was placed in a ceramic dish, placed in a furnace, and heated to 900 °C using a pre-programmed heat-up rate of 20 °C / minute. Once this temperature was achieved, the furnace was held at 900 °C for 30 mins and then turned off. The sample in the furnace was allowed to cool slowly to room temperature overnight before it was removed.TABLE 7. PROCESS CONDITIONS AND PERFORMANCE OF EXAMPLES 27-29AND COMPARATIVE EXAMPLE JExample Temp (°C) Time (min) ARI (%) d50 (pm) % >105 pm 27 900 15 81 197 78.8 28 900 60 85 239 82.3 29 900 30 96 369 98.4J 1400 15 93 299 87.5TI0014-W001

[0061] Example 29 also showed high ARI and PSD, indicating successful use of lower total water in the batch and scaled-up operation compared to previous examples.

Claims

TI0014-W001CLAIMSWhat is claimed is:

1. A process for agglomerating fine ore particles comprising:a. obtaining an aqueous binder solution;b. mixing the binder solution with fine ore particles to form a granulated green mix;c. drying the granulated green mix to reduce moisture content to form a dry mixture; andd. calcining the dry mixture to form dry ore agglomerates;where at least 50% by weight of the fine ore particles have a particle size below 105 pm; andwhere the binder solution comprises an aqueous solution of a compound selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH, such that the binder solution comprises at most 1 % by weight organic compounds, based on the solids weight of the granulated green mix.

2. The process of claim 1, where shear is applied to the binder solution mixture during step b or to the granulated green mixture prior to drying step c.

3. The process of claim 2, where shear is applied at a shear rate of at least about 50 / s, preferably at least about 100 / s, and more preferably at least about 150 / s.

4. The process of any of the preceding claims, where the binder solution and fine ore particles of step b or granulated green mix of step b are mixed by hand, in a stand mixer, pin mixer, fluidized bed mixer, mechanical mixer, aeromechanical mixer, or intensive planetary mixer.

5. The process of any of the preceding claims, where the fine ore particles are from Ti-bearing feedstock.

6. The process of any of the preceding claims, where the fine ore particles are from ilmenite or slag fines.

7. The process of any of the preceding claims, where the fine ore particles comprise at least about 20% by weight TiO2, preferably at least about 30% by weight TiO₂, and more preferably at least about 40% by weight TiO₂, based on the total weight of the fine ore particles.TI0014-W0018. The process of any of the preceding claims, where at least 60% by weight of the fine ore particles have a particle size below 105 pm.

9. The process of any of the preceding claims, where at least 50% by weight of the dry ore agglomerates have a particle size above 105 pm, preferably at least 60% by weight of the dry ore agglomerates have a particle size above 105 pm, and more preferably at least 70% by weight of the dry ore agglomerates have a particle size above 105 pm.

10. The process of any of the preceding claims, where the calcining step is performed at a temperature of at most about 975 °C, preferably at most about 950 °C, and more preferably at most about 925 °C.

11. The process of any of the preceding claims, where the calcining step is performed at a temperature of at least about 600 °C, preferably at least about 700 °C, and more preferably at least about 800 °C.

12. The process of any of the preceding claims, where the dry ore agglomerates have a particle size d50 of at least about 100 pm, preferably at least about 150 pm, and more preferably at least about 200 pm.

13. The process of any of the preceding claims, where the dry ore agglomerates have an attrition resistance (ARI) of at least about 50%, preferably at least about 60%, and more preferably at least about 70%.

14. The process of any of the preceding claims, where the granulated green mix comprises about 2 to about 7% by weight of a binder compound, based on the total weight of the granulated green mix.

15. The process of any of the preceding claims, where the granulated green mix comprises about 3% to about 15% by weight water, based on the total weight of the granulated green mix.

16. The process of any of the preceding claims, where the binder compound comprises sodium silicate having a molar ratio of SiO₂ : Na₂O of about 0.5:1 to about 3.75:1, preferably a molar ratio of SiO₂ : Na₂O of about 2:1 to about 3:1.TI0014-W00117. The process of any of the preceding claims, where the binder solution has a solids content of about 10 to about 40% by weight, based on the total weight of the binder solution.

18. The process of any of the preceding claims, where the binder compound comprises a mixture of sodium silicate and either NaOH or KOH.

19. The process of any of the preceding claims, where the binder solution comprises TiO₂ waste water.

20. The process of claim 18, where the binder solution further comprises NaOH, NaCI, suspended TiO₂ particles, HCl, or mixtures thereof.

21. The process of any of the preceding claims, further comprising the step c1 of crushing the dry mixture to form a crushed dry mixture prior to performing calcining step d.

22. The process of any of the preceding claims, further comprising the step c2 of sieving the dry mixture or crushed dry mixture to remove particles above a desired particle size to form a sieved mixture prior to performing calcining step d.

23. The process of any of the preceding claims, where no additional water is added at step b to form the granulated green mix.

24. A composition of dry ore agglomerates comprising fine ore particles distributed within a matrix of a binder compound formed by the process of any of the preceding claims.

25. A composition of dry ore agglomerates comprising fine ore particles distributed within a matrix of a binder compound,where at least 50% by weight of the fine ore particles have a particle size below 105 pm; andwhere the binder compound is selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH, such that the matrix comprises at most 1% by weight organic compounds, based on the total weight of the dry ore agglomerates.TI0014-W00126. The composition of any of the preceding claims, where the fine ore particles are from ilmenite or slag fines.

27. The composition of any of the preceding claims, where the fine ore particles are from Ti-bearing feedstock.

28. The composition of any of the preceding claims, where the fine ore particles comprise at least about 20% by weight TiO2, preferably at least about 30% by weight TiOs, and more preferably at least about 40% by weight TiOs, based on the total weight of the fine ore particles.

29. The composition of any of the preceding claims, where at least 60% by weight of the fine ore particles have a particle size below 105 pm.

30. The composition of any of the preceding claims, where at least 50% by weight of the dry ore agglomerates have a particle size above 105 pm, preferably at least 60% by weight of the dry ore agglomerates have a particle size above 105 pm, and more preferably at least 70% by weight of the dry ore agglomerates have a particle size above 105 pm.

31. The composition of any of the preceding claims, where the dry ore agglomerates have a particle size d50 of at least about 100 pm, preferably at least about 150 pm, and more preferably at least about 200 pm.

32. The composition of any of the preceding claims, where the dry ore agglomerates have an attrition resistance (ARI) of at least about 50%, preferably at least about 60%, and more preferably at least about 70%.

33. The composition of any of the preceding claims, where the binder compound comprises about 2 to about 7% by weight of the granulated green mix, based on the total weight of the granulated green mix.

34. The composition of any of the preceding claims, where the binder compound comprises sodium silicate having a molar ratio of SiO2: Na2O of about 0.5:1 to about 3.75: 1, preferably a molar ratio of SiO₂ : Na₂O of about 2:1 to about 3:1.

35. The composition of any of the preceding claims, where the binder compound comprises a mixture of sodium silicate and either NaOH or KOH.TI0014-W00136. The composition of any of the preceding claims, where the matrix further comprises NaOH, NaCI, suspended TiO2 particles, HCI, or mixtures thereof.

37. A process for agglomerating fine ore particles comprising:a. obtaining an aqueous binder solution;b. mixing the binder solution with fine ore particles to form a granulated green mix;c. drying the granulated green mix to reduce moisture content to form a dry mixture; andd. calcining the dry mixture to form dry ore agglomerates;where at least 50% by weight of the fine ore particles have a particle size below 105 pm; andwhere the binder solution comprises an aqueous solution of a compound selected from sodium silicate or mixtures of sodium silicate with either NaOH or KOH.

38. The process of claim 37, where shear is applied to the binder solution mixture during step b or to the granulated green mixture prior to drying step c.

39. The process claim 38, where shear is applied at a shear rate of at least about 50 / s, preferably at least about 100 / s, and more preferably at least about 150 / s.

40. The process of claims 37-39, where the binder solution and fine ore particles of step b or granulated green mix of step b are mixed by hand, in a stand mixer, pin mixer, fluidized bed mixer, mechanical mixer, aeromechanical mixer, or intensive planetary mixer.

41. The process of claims 37-40, where the fine ore particles are from Ti-bearing feedstock.

42. The process of claims 37-41, where the fine ore particles are from ilmenite, leucoxene, or slag fines.

43. The process of claims 37-42, where the fine ore particles comprise at least about 20% by weight TiO₂, preferably at least about 30% by weight TiO₂, and more preferably at least about 40% by weight TiO₂, based on the total weight of the fine ore particles.TI0014-W00144. The process of claims 37-43, where the fine ore particles comprise at most about 80% by weight TiO2, preferably at most about 75% by weight TiO2, and more preferably at most about 70% by weight TiO₂, based on the total weight of the fine ore particles.

45. The process of claims 37-44, where at least 60% by weight of the fine ore particles have a particle size below 105 pm.

46. The process of claims 37-45, where at least 50% by weight of the dry ore agglomerates have a particle size above 105 pm, preferably at least 60% by weight of the dry ore agglomerates have a particle size above 105 pm, and more preferably at least 70% by weight of the dry ore agglomerates have a particle size above 105 pm.47 The process of claims 37-46, where the calcining step is performed at a temperature of at most about 1000 °C, preferably at most about 975 °C, and more preferably at most about 925 °C.

48. The process of claims 37-47, where the calcining step is performed at a temperature of at least about 600 °C, preferably at least about 700 °C, and more preferably at least about 800 °C.

49. The process of claims 37-48, where the dry ore agglomerates have a particle size d50 of at least about 100 pm, preferably at least about 150 pm, and more preferably at least about 200 pm.

50. The process of claims 37-49, where the dry ore agglomerates have an attrition resistance (ARI) of at least about 50%, preferably at least about 60%, and more preferably at least about 70%.

51. The process of claims 37-50, where the granulated green mix comprises about 2 to about 7% by weight of the binder compound, based on the total weight of the granulated green mix.

52. The process of claims 37-51, where the granulated green mix comprises about 3% to about 15% by weight water, based on the total weight of the granulated green mix.TI0014-W00153. The process of claims 37-52, where the binder compound comprises sodium silicate having a molar ratio of SiO₂ : Na₂O of about 0.5:1 to about 3.75:1, preferably a molar ratio of SiO₂ : Na₂O of about 2:1 to about 3:1.

54. The process of claims 37-53, where the binder solution has a solids content of about 10 to about 40% by weight, based on the total weight of the binder solution.

55. The process of claims 37-54, where the binder compound comprises a mixture of sodium silicate and either NaOH or KOH.

56. The process of claims 37-55, where the binder solution comprises TiO2 waste water.

57. The process of claim 56, where the binder solution further comprises NaOH, NaCI, suspended TiO₂ particles, HCl, or mixtures thereof.

58. The process of claims 37-57, further comprising the step c1 of crushing the dry mixture to form a crushed dry mixture prior to performing calcining step d.

59. The process of claims 37-58, further comprising the step c2 of sieving the dry mixture or crushed dry mixture to remove particles above a desired particle size to form a sieved mixture prior to performing calcining step d.

60. The process of claims 37-59, where no additional water is added at step b to form the granulated green mix.

61. A composition of dry ore agglomerates comprising fine ore particles distributed within a matrix of a binder compound formed by the process of claims 37-60.

62. A composition of dry ore agglomerates comprising fine ore particles adhered at an interface between particles with a matrix of a binder compound, where at least 50% by weight of the fine ore particles have a particle size below 105 pm; andwhere the binder compound is selected from calcined sodium silicate or mixtures of sodium silicate with either NaOH or KOH.

63. The composition of claim 62, where the fine ore particles are from ilmenite, leucoxene, or slag fines.TI0014-W00164. The composition of claims 62-63, where the fine ore particles are from Ti- bearing feedstock.

65. The composition of claims 62-64, where the fine ore particles comprise at least about 20% by weight TiO₂, preferably at least about 30% by weight TiO₂, and more preferably at least about 40% by weight TiO₂, based on the total weight of the fine ore particles.

66. The composition of claims 62-65, where the fine ore particles comprise at most about 80% by weight TiO₂, preferably at most about 75% by weight TiO₂, and more preferably at most about 70% by weight TiO₂, based on the total weight of the fine ore particles.

67. The composition of claims 62-66, where at least 60% by weight of the fine ore particles have a particle size below 105 pm.

68. The composition of claims 62-67, where at least 50% by weight of the dry ore agglomerates have a particle size above 105 pm, preferably at least 60% by weight of the dry ore agglomerates have a particle size above 105 pm, and more preferably at least 70% by weight of the dry ore agglomerates have a particle size above 105 pm.

69. The composition of claims 62-68, where the dry ore agglomerates have a particle size d50 of at least about 100 pm, preferably at least about 150 pm, and more preferably at least about 200 pm.

70. The composition of claims 62-69, where the dry ore agglomerates have an attrition resistance (ARI) of at least about 50%, preferably at least about 60%, and more preferably at least about 70%.

71. The composition of claims 62-70, where the dry ore agglomerates comprise the binder compound in an amount of about 2 to about 7% by weight of the dry ore agglomerates, based on the total weight of the dry ore agglomerates.

72. The composition of claims 62-71, where the binder compound comprises sodium silicate having a molar ratio of SiO₂ : Na₂O of about 0.5:1 to about 3.75:1, preferably a molar ratio of SiO₂ : Na₂O of about 2:1 to about 3:1.TI0014-W00173. The composition of claims 62-72, where the binder compound comprises a mixture of sodium silicate and either NaOH or KOH.

74. The composition of claims 62-73, where the matrix further comprises NaOH, NaCI, suspended TiO₂ particles, HCl, or mixtures thereof.

75. The process of claims 1-23, where the fine ore particles comprise at most about 80% by weight TiO2, preferably at most about 75% by weight TiO2, and more preferably at most about 70% by weight TiO2, based on the total weight of the fine ore particles.

76. The composition of claims 25-36, where the fine ore particles comprise at most about 80% by weight TiO2, preferably at most about 75% by weight TiO2, and more preferably at most about 70% by weight TiO2, based on the total weight of the fine ore particles.

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