Porous composite feedstock and use thereof

Abstract

The present invention relates to a porous composite feedstock for metal chloride preparation, comprising a metal oxide containing material,; and / or a first additive; and a binder; wherein the porous composite feedstock is in particulate form; wherein the water content of the porous composite feedstock is in the range of from 0.01 to 5 wt.% based on the weight of the porous composite feedstock; and wherein the porous composite feedstock has a poured bulk density in the range of from 0.2 g / cm3 and 2.0 g / cm3.

Description

[0001] Porous Composite Feedstock and use thereof

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a porous composite feedstock for metal chloride preparation, the use of a porous composite feedstock in the preparation of a metal chloride and the use of a porous composite feedstock as fluidized bed stabilizer in the preparation of a metal chloride. Further, the invention refers to a method for preparing a metal chloride.

[0004] TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0005] Carbochlorination processes are those in which metal oxides are converted into their corresponding metal chlorides in the presence of chlorine gas and carbonaceous materials. The most common carbochlorination processes involve the processing of feedstocks such as ores and slags containing oxides of refractory metals, among them, niobium, tantalum, tungsten, molybdenum and rhenium or oxides of rare earth metals like cerium, neodymium, samarium or of oxides of light metals such as aluminum, silicon, vanadium or titanium or other metals like zirconium. Metal chlorides often show relatively low vapor pressure and can be removed from the original solid matrices by sublimation or can be purified by fractional sublimation or distillation thereby exploiting their varying boiling points, with or without the use of solvents. In addition, metal chlorides can also be purified by extraction or other separation methods.

[0006] Usually, metal chlorides are further processed to metals, metal alloys or purified oxides or hydroxides all of which are economically attractive. One of the most important carbochlorination process is the chloride process for the manufacture of titanium dioxide and in particular TiO2 pigment particles.

[0007] Titanium dioxide is either manufactured by the well-established sulfate process or the chloride process. The latter uses a titanium-containing feedstock which is subjected to a carbochlorination process. The thus obtained chlorides are subsequently separated by resublimation or distillation. The titanium tetrachloride is finally converted to titanium dioxide, and the chlorine which is set free from the afore-mentioned reaction is separated, and reused in the reaction with the titanium-containing feedstock. Amongst other reasons, the reuse of chlorine makes the chloride process economically attractive over the sulphate process.

[0008] A significant source of cost and environmental carbon footprint in the manufacture of metal chlorides, or in TiO2 pigment particle production using TiCL, arises from obtaining suitable carbonaceous and metal oxide containing feedstocks, such as titaniferous feedstocks, for the carbochlorination process. Some limiting factors on the types of feedstocks that can be used in the carbochlorination process are the size and moisture content of the feedstock particles, as well as the amount and type of metal, in particular Ti, and / or C content of the feedstock. In the past, conventional methods required that feedstocks be pre-processed to fall within relatively narrow range requirements for suitable particle size, moisture, and content, which increases costs and environmental impact of the overall process. Therefore, it would be desirable to be able to use a wider variety of feedstocks of both metal oxide containing materials, such as titaniferous materials, and additives, such as carbonaceous materials.

[0009] Currently in carbochlorination processes the coke of choice is petroleum coke with a specific particle size. Due to the small particle size and low density, fine petroleum cokes which are available at lower costs, are unsuitable for the carbochlorination processes as the aredischarged from the reactor whitout participating in the reaction. The same applies to green and sustainable cokes descending from renewable raw materials such as char coal and bio char which due to their processing display low particle density and low poured bulk density on their own.

[0010] One such readily available alternative source for cokes, also called additives such as carbonaceous materials, would be the unused recycled coke materials from the carbochlorination process itself and / or different grades and / or sources of coke and other carbonaceous material. However, conventionally, there have been significant barriers to being able to do this because these recycled materials are typically too small (too fine) and / or have too much moisture for suitable re-introduction into the carbochlorination process. For example, wet petroleum coke (also referred to as “wet petcoke” herein before and after) would be an ideal source of carbonaceous material if it could be transformed into a usable form. Wet petcoke comprises petroleum coke particles with a high moisture content, such as 30 to 40 wt.% moisture, produced by a recycling process, such as, from the unreacted solids fraction exhausted from a carbochlorination reactor in its normal operation mode for generating TiCk However, wet petcoke typically cannot be successfully used in the carbochlorination fluidized bed reactor because it contains excessive moisture (30-40 wt.%) and typically has too many fine particles (80% < 250 pm) to be introduced back to the reactor and successfully participate in the carbochlorination reaction. Similarly, petcoke fines, which typically have 80% or more of the particles with a d50 less than 500 pm, would also be a desirable source of carbonaceous material because these are typically available from the market at lower costs and are usually dry and free flowing. However, these petcoke fines are also usually too fine to be introduced back to the reactor in order to successfully participate in the carbochlorination reaction. In addition, although petcoke fines typically are in the form of a dry powder with a moisture of 5 wt.% or less, petcoke fines can sometimes contain moisture content of up to 20 wt.% even while usually remaining free flowing. Another less expensive source of carbonaceous feedstock is biocoke, which is readily available from the market or from the manifold of manufacturing processes, such as hydrothermal carbonization and / or methane pyrolysis. Use of biocoke could also reduce the carbon footprint of the carbochlorination process by using at least a fraction of renewable resources and hence to move the TiC>2 pigment manufacturing industry towards carbon neutrality. However, these biocokes and cokes made from renewable starting materials also typically are too fine and / or too moist for use in the carbochlorination reaction.

[0011] An alternative source of metal oxide containing feedstock, such as titaniferous feedstock material, would also be desirable. For example, it would be desirable to be able to use slag fines and other types of metal oxide containing, preferably titaniferous, fines readily available from the market as a source of feedstock materials because they often have metal contents of 92% or more and are less expensive to obtain. Unfortunately, these slag fines and other metal oxide or metal containing fines typically have particle size distributions of more than 80% of the particles having a d50 less than 100 pm, which is too fine to be used in the current carbochlorination reactors. In addition, such metal or metal oxide containing fine materials also often display moisture of up to 5 wt.% in order to prevent dusting during transportation, which is too wet to be used in the current carbochlorination reactors.

[0012] Therefore, it would be desirable to be able to use a wider variety of source materials for the additives, such as carbonaceous materials, and / or metal oxide containing materials, such as titaniferous materials, as feedstock in carbochlorination processes in order be able to reduce the cost of the input materials. In addition, it would also be desirable to have a way to be able to recycle the unused materials from carbochlorination processes as source of additives, such as carbonaceous materials, and / or metal oxide containing materials, such as titaniferous materials, that can be used again as feedstock in carbochlorination processes in order to reduce waste streams and the environmental impact of the metal chloride manufacturing process.

[0013] OBJECT AND SUMMARY OF THE INVENTION

[0014] It is the object of the present invention to provide a feedstock material for the metal chloride preparation having favourable properties and which is advantageous for running a stable metal chloride preparation process. Besides, allowing the application of a wide range of materials is also an object of the present invention. The object is achieved by the porous composite feedstock, the use of the porous composite feedstock in the preparation of metal chloride, the use of the porous composite feedstock as fluidized bed stabilizer as well as the method for preparing metal chloride.

[0015] In a first aspect the present invention relates to a porous composite feedstock for metal chloride preparation, preferably TiCk preparation, comprising, preferably consisting of, a metal oxide containing material, preferably a titaniferous material, more preferably a first titaniferous material; and / or a first additive, preferably a first carbonaceous material; and a binder, preferably a binder composition; wherein the porous composite feedstock is in particulate form; wherein the water content of the porous composite feedstock is in the range of from 0.01 to 5 wt.% based on the weight of the porous composite feedstock; and wherein the porous composite feedstock has a poured bulk density in the range of from 0.2 g / cm3and 2.0 g / cm3.

[0016] In as second aspect, the invention is directed to the use of a porous composite feedstock according to the invention in the preparation of metal chloride, preferably TiCk, in a carbochlorination process, preferably in a carbochlorination process in a fluidized bed reactor.

[0017] In a further aspect, the invention refers to the use of the porous composite feedstock according to the invention as fluidized bed stabilizer in the preparation of a metal chloride, preferably TiCk.

[0018] In a yet further aspect, the invention relates to a method for preparing metal chloride, preferably TiCk, comprising, preferably consisting of, the steps of adding a solid feedstock comprising alkaline earth metal salts and alkaline earth metal oxides to a reaction vessel, preferably to a fluidized bed reactor; adding the porous composite feedstock according to the invention to the reaction vessel, wherein the composite feedstock may be added before or after the solid feedstock; mixing the solid feedstock and the porous composite feedstock forming a reaction mixture.

[0019] Further advantageous embodiments of the invention are stated in the dependent claims.

[0020] DESCRIPTION

[0021] These and other aspects, features and advantages of the invention become obvious to the skilled person from the study of the following detailed description and claims. Each feature from one aspect of the invention can be employed in any other aspect of the invention. Numerical ranges stated in the format "from x to y" include the mentioned values and the values that are within the respective measuring accuracy as known to the skilled person. If several preferred numerical ranges are stated in this format, it is a matter of course that all ranges formed by the combination of the various end points are also included.

[0022] The terms “a” and “an” as used herein to introduce a feature are used as open-ended, inclusive terms to refer to at least one, or one or more of the feature, and are not limited to only one such feature unless otherwise expressly indicated. Similarly, use of the term “the” in reference to a feature previously introduced using the term “a” or “an” does not thereafter limit the feature to only a single instance of such feature unless otherwise expressly indicated.

[0023] In a first aspect the present invention relates to a porous composite feedstock for metal chloride preparation, preferably TiCU preparation, comprising, preferably consisting of, a metal oxide containing material, preferably a titaniferous material, more preferably a first titaniferous material; and / or a first additive, preferably a first carbonaceous material; and a binder, preferably a binder composition; wherein the porous composite feedstock is in particulate form; wherein the water content of the porous composite feedstock is in the range of from 0.01 to 5 wt.%, preferably of from 0.02 to 2 wt.%, more preferably of from 0.03 to 1 wt.%, even more preferably of from 0.04 to 0.5 wt.% based on the weight of the porous composite feedstock; and wherein the porous composite feedstock has a poured bulk density in the range of from 0.2 g / cm3and 2.0 g / cm3, preferably of from 0.3 to 1 .6 g / cm3, more preferably of from 0.4 and 1 .2 g / cm3, and even more preferably of from 0.5 to 0.9 g / cm3.

[0024] The porous composite feedstock according to the invention can be applied in the preparation of metal chlorides. Various materials and / or additives which are combined with a binder and are in particulate form can be used. The porous composite feedstock according to the invention has an advantageous combination of form, water content and poured bulk density so that it is particularly suited for the application in fluidized bed reactors.

[0025] In a preferred embodiment the porous composite feedstock has a particle size distribution (PSD) in the range of from 0.1 mm to 10 mm, preferably of from 0.2 mm to 6 mm, more preferably of form 0.3 mm to 5 mm, and even more preferably of from 0.4 to 3 mm.

[0026] The particle size distribution (PSD) can be determined by sieve analysis, where a sample of the aggregate is sieved through a series of progressively finer sieves to separate the particles by size. The mass or percentage of the sample that passes through each sieve is then measured and used to calculate the PSD.

[0027] The metal oxide containing material can be any metal oxide used as starting material of carbochlorination process comprised of any metal of interest such as refractory metals, among them, niobium, tantalum, tungsten, molybdenum and rhenium, rare earth metals like cerium, neodymium, samarium or light metals such as aluminum, silicon, vanadium or titanium or other metals like zirconium. Preferably, the ores and slags containing the above can be used. The metal oxide containing material may also comprise further metal salts of the above mentioned metals.

[0028] In a preferred embodiment the metal oxide containing material is a titaniferous material, preferably a first titaniferous material.

[0029] Preferably the titaniferous material, preferably the first titaniferous material, is selected from the group consisting of natural rutile, synthetic rutile, titaniferous slag, recycled titaniferous slags, residual slags, ilmenite and combinations thereof, more preferably the titaniferous material, preferably the first titaniferous material, is selected from the group consisting of titaniferous slag, rutile, synthetic rutile, ilmenite and combinations thereof. The residual slag can originate from the iron and steel industry.

[0030] According to a preferred embodiment the metal oxide containing material, preferably the titaniferous material, has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm.

[0031] In another preferred embodiment the first additive is a first carbonaceous material.

[0032] Preferably the first carbonaceous material is selected from the group consisting of coke, petroleum coke, fine petroleum coke, wet petroleum coke, recycled petroleum coke, wet recycled petroleum coke, biocoke, carbon containing slag fines, charcoal, green petrol coke fines, calcined petroleum coke, gilsonite, anthracite coal, pyrolysis coke, hydrothermal carbon (HTC), biochar and combinations thereof. “Fine petroleum coke”, as used herein refers to a petroleum coke with a poured bulk density of 0.5 g / cm3or less, preferably 0.4 g / cm3or less.

[0033] In a preferred embodiment the carbonaceous material is selected from the group consisting of fine petroleum coke, recycled petroleum coke, bio char, char coal, pyrolyzed brown coal, pyrolyzed peat, and pyrolyzed coke can be used. Further, substances such as cokes generated from organic recycled materials or secondary or tertiary raw materials by e.g. pyrolysis and similar processes that generate coke, hydrothermally generated coke (HTC) from sewage sludge, manure, wood, straw or other agricultural residues, appropriate fractions of municipal waste.

[0034] According to another preferred embodiment the amount of first additive, preferably first carbonaceous material, in the porous composite feedstock is in the range of from 0 to 95 wt.%, preferably is in the range of from 10 to 90 wt.%, and more preferably is in the range of from 10 to 60 wt.% based on the weight of the composite feedstock.

[0035] In a further preferred embodiment the first additive is porous, preferably the first carbonaceous material is porous. In yet another preferred embodiment the first additive, preferably the first carbonaceous material, has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm.

[0036] It is further preferred that the porous composite feedstock comprises a metal oxide containing material, preferably a titaniferous material, more preferably a first titaniferous material, and a first additive, preferably a first carbonaceous material.

[0037] In another preferred embodiment the binder in the porous composite feedstock is an aqueous binder.

[0038] As used herein, the term aqueous binder(s) refers to binder(s) that contain the major fraction of hydrogen (H) in form of free water (H2O), or in case of starches, sugars, molasses, etc., in the form of -C-O-H groups, stemming from e.g. alcohol or aldehyde groups. This does not generally exclude the presence of water. This is in contrast to non-aqueous binders, which contain hydrogen (H) directly bound to carbon (C-H bond).

[0039] It is further preferred that the binder is selected from the group consisting of lignosulfonate, carbohydrates, polyvinyl alcohol, water-based plasticizers, tannins, lignin, inorganic binders and combinations thereof; and / or the binder is selected from the group consisting of lignosulfonate, glycerin, saccharides, molasses, starch, modified starch, cellulose, including carboxymethyl cellulose (CMC), lignocellulose, functionalized lignocellulose, lignin, polyvinyl alcohol, water-based plasticizers, tannins, cement, bentonite, waterglass, aluminum hydroxide, metakaolin, clay, carbon black, and combinations thereof.

[0040] In yet another preferred embodiment the amount of binder is in the range of from 0.5 to 25 wt.%, preferably of from 1 to 20 wt.%, more preferably of from 2 to 10 wt.%, and more preferably of from 2 to 5 wt.% based on the weight of the porous composite feedstock.

[0041] In another preferred embodiment the porous composite feedstock comprises 2 to 20 wt.%, preferably 3 to 12 wt.%, and more preferably 5 to 10 wt.% of starch or modified starch based on the weight of the composite feedstock; and / or In another preferred embodiment the porous composite feedstock comprises 2 to 20 wt.%, preferably 3 to 12 wt.%, and more preferably 5 to 10 wt.% of carboxy methyl cellulose based on the weight of the composite feedstock; and / or wherein the porous composite feedstock comprises 2 to 20 wt.%, preferably 3 to 12 wt.%, and more preferably 5 to 10 wt.% of waterglass based on the weight of the composite feedstock.

[0042] According to yet another preferred embodiment the binder comprises more than 20 wt.%, preferably more than 35 wt.%, more preferably more than 50 wt.%, and even more preferably 20 to 75 wt.% of waterglass based on the weight of the binder; and / or the binder comprises more than 20 wt.%, preferably more than 35 wt.%, more preferably more than 50 wt.%, and even more preferably 20 to 75 wt.% of starch or modified starch based on the weight of the binder.

[0043] According to another preferred embodiment the binder comprises 2 to 20 wt.% of modified starch, preferably 3 to 10 wt.% of modified starch, and more preferably 3 to 5 wt.% of modified starch; and / or the binder comprises 2 to 20 wt.% of waterglass, preferably 5 to 10 wt.% of waterglass, and more preferably 5 or 7 wt.% of waterglass; and / or the binder comprises 1 to 20 wt.% of aluminum hydroxide, preferably 1 to 6 wt.% of aluminum hydroxide, and more preferably 1 to 3 wt.% of aluminum hydroxide.

[0044] In another preferred embodiment the water content of the porous composite feedstock is less than 4 wt.%, preferably less than 1 wt.%, more preferably less than 0.5 wt.% based on the weight of the composite feedstock.

[0045] In a further preferred embodiment the water content of the porous composite feedstock is in the range of from 0.01 to 4 wt.%, preferably of from 0.02 to 1 wt.%, more preferably of from 0.03 to 0.5 wt.%, and even more preferably of from 0.04 to 0.4 wt.% based on the weight of the composite feedstock.

[0046] In yet another preferred embodiment the content of volatile compounds comprising hydrogen and oxygen other than water is less than 1 wt.%, and preferably less than 0.5 wt.% based on the weight of the composite feedstock.

[0047] In a further preferred embodiment the content of volatile compounds comprising hydrogen and oxygen other than water is in the range of from 0.01 to 2 wt.%, preferably is in the range of from 0.02 to 1 wt.%, preferably is in the range of from 0.03 to 0.5 wt.% based on the weight of the composite feedstock.

[0048] It is preferred that the porous composite feedstock is a homogeneous mixture of a metal oxide containing material and / or a first additive, and a binder. It is a preferred embodiment that the porous composite feedstock is a homogeneous mixture of a titaniferous material, a first carbonaceous, and a binder.

[0049] According to a preferred embodiment the porous composite material is an extruded composite feedstock. In this embodiment porous composite feedstock is an extrudate. Preferably the composite feedstock has been prepared by using a stiff vacuum extrusion process.

[0050] In another preferred embodiment the porous composite feedstock comprises a second titaniferous material, wherein the second titaniferous material is different from a first titaniferous material.

[0051] According to a preferred embodiment the second titaniferous material is selected from the group consisting of titaniferous slag, rutile, synthetic rutile, ilmenite and combinations thereof.

[0052] In a yet another preferred embodiment the second titaniferous material has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm.

[0053] In a further preferred embodiment the porous composite feedstock comprises a second additive, wherein the second is different from the first additive, preferably the second additive is a second carbonaceous material.

[0054] It is further preferred that the second additive is porous, preferably the second carbonaceous material is porous.

[0055] According to a preferred embodiment the second carbonaceous material is selected from the group consisting of coke, petroleum coke, wet petroleum coke, recycled petroleum coke, wet recycled petroleum coke, biocoke, carbon containing slag fines, charcoal, green petrol coke fines, calcined petroleum coke, gilsonite, anthracite coal, pyrolysis coke, hydrothermal carbon (HTC), biochar and combinations thereof. In another preferred embodiment the second additive is a non-carbonaceous material, preferably a non-carbonaceous porous material, and more preferably selected from the group consisting of porous inorganic material, porous mineral, bentonite, diatomite, zeolite, volcanic tuffs, porous carbides, pumice, and combinations thereof.

[0056] According to a yet another preferred embodiment the second additive has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm.

[0057] According to a preferred embodiment the porous composite feedstock has a hardness, determined by the measurement of the compression strength as specified by ASTM D4179-01 (2006), of at least 0.8 N / mm2, preferably at least 0.9 N / mm2, more preferably at least 1.4 N / mm2, and even more preferably of at least 2.0 N / mm2; and / or a porosity, as measured by mercury intrusion and extrusion measurement method, of 10 to 90%, preferably of 20 to 80% and more preferably of 30 to 70%; and / or a porosity, as measured by the low-temperature nitrogen adsorption measurement method according to Barrett, Joyner, and Halenda, of 10 to 90%, preferably of 20 to 80% and more preferably of 30 to 70%; and / or a BET value of more than 10 m2 / g, preferably more than 100 m2 / g, and even more preferably more than 200 m2 / g, and preferably not exceeding 2000 m2 / g.

[0058] The hardness, determined by the measurement of the compression strength as specified by ASTM D4179-01 (2006), is preferably in the range of from 0.8 to 10 N / mm2.

[0059] In a second aspect the present invention relates to the use of a porous composite feedstock according to the invention in the preparation of metal chloride, preferably TiCU, in a carbochlorination process, preferably in a carbochlorination process in a fluidized bed reactor. It should be understood that any feature and / or embodiment discussed above in connection with the porous composite feedstock according to the invention apply by analogy to this aspect.

[0060] According to a preferred embodiment the porous composite feedstock is added to the fluidized bed reactor during the carbochlorination process.

[0061] In a carbochlorination process also a solid feedstock is added to the reaction vessel, preferably a fluidized bed reactor.

[0062] In a preferred embodiment the porous composite feedstock is added before the solid feedstock.

[0063] According to another preferred embodiment the porous composite feedstock is added after the solid feedstock.

[0064] In another aspect the invention relates to the use of the porous composite feedstock according to the invention as fluidized bed stabilizer in the preparation of a metal chloride, preferably TiCk

[0065] It should be understood that any feature, embodiment and / or aspect discussed above in connection with the porous composite feedstock according to the invention and the use in the preparation of metal chloride in a carbochlorination process apply by analogy to this aspect.

[0066] In a further aspect the invention relates to a method for preparing metal chloride, preferably TiCU, comprising, preferably consisting of, the steps of adding a solid feedstock comprising alkaline earth metal salts and alkaline earth metal oxides to a reaction vessel, preferably to a fluidized bed reactor; adding the porous composite feedstock according to the invention to the reaction vessel, wherein the composite feedstock may be added before or after the solid feedstock. mixing the solid feedstock and the porous composite feedstock forming a reaction mixture. It should be understood that any feature, embodiment and / or aspects discussed above in connection with the porous composite feedstock according to the invention, the use in the preparation of metal chloride in a carbochlorination process and the use as fluidized bed stabilizer apply by analogy to this aspect.

[0067] According to a preferred embodiment the method is a carbochlorination process.

[0068] In yet another preferred embodiment the method comprising the further step of removing alkaline earth metal salts, preferably alkaline earth metal chlorides, more preferably MgCh and CaCh, from the reaction mixture in the reaction vessel, preferably discharging disintegrated porous composite feedstock particles loaded with alkaline earth metal salts, preferably alkaline earth metal chlorides, more preferably MgCI2 and CaCI2, from the reaction vessel.

[0069] DESCRIPTION OF THE DRAWINGS

[0070] FIG. 1 is a schematic representation of an example of a method and processing line for manufacturing a porous composite feedstock according to the invention;

[0071] FIG. 2 is an end view of a perforated extrusion disc for a vacuum extruder;

[0072] FIG. 3 shows an image obtained by light microscopy of an inventive porous composite feedstock particle (shown is a particle with pet coke particles (dark spots) which are embedded in a matrix of metal oxide containing material and binder).

[0073] The following description is meant to describe what is shown in the drawings and / or various contemplated embodiments shown and / or related to what is shown in the drawings. The embodiment(s) shown in the drawings are non-limiting examples and do not themselves define the invention.

[0074] Any of the features shown and / or described in relation to one embodiment may be combined with any one or more features shown and / or described relative to another embodiment or aspect. Any dimensions shown in the drawings and / or described hereinafter are exemplary only and are not intended to limit the scope of the invention. FIG. 1 schematically illustrates an example of a system 10, such as an industrial chemical manufacturing line, for preparing a porous composite feedstock according to the invention. One or more storage structures, such as silos 12, contain one or more feedstocks such as metal oxide containing materials, additives such as carbonaceous material, respectively. Those feedstock can be in particulate form. For example, there may be a single silo 12 containing only a single feedstock, or there may be multiple silos 12 containing any one or more of the particulate feedstocks discussed herein that can be used to make the porous composite feedstocks, or a single silo could contain multiple types of particulate feedstocks. The feedstock(s) can be carbonaceous materials, such as wet petcoke and / or petcoke fines, and / or metal oxide containing materials such as titaniferous material, such as a titanium carrying ore or a TiO2 carrying material. Other types of carbonaceous materials that could be used include HTC coke and / or pyrolysis coke.

[0075] A second storage structure(s), such as a second silo 14, contains any one or more of the binders, preferably aqueous binder(s), discussed herein or otherwise suitable for binding the feedstocks in a stiff vacuum extrusion process. As used herein, the term aqueous binders refers to binders that contain the major fraction of hydrogen (H) in form of free water (H2O), or in case of starches, sugars, molasses, etc., in the form of -C-O-H groups, i.e. alcohol groups. This does not generally exclude the presence of water. This is in contrast to nonaqueous binders, which contain hydrogen (H) directly bound to carbon (C-H bond). A variety of different aqueous binders could be used in the process, either separately or in combination, such any one or more of lignosulfonate, carbohydrates, including glycerin, sugars, molasses, starch, modified starch, cellulose, including carboxymethyl cellulose (CMC), functionalized lignocellulose, lignosulfonate, polyvinyl alcohol (PVA), water-based plasticizers, tannins, and inorganic binders including cement, bentonite, waterglass, aluminum hydroxide, metakaolin, and combinations thereof. In some embodiments, the aqueous binder is composed primarily of waterglass, modified starch dry powder, aluminum hydroxide powder, or mixtures thereof. For example, the binder can have a composition of 2 to 20 wt.% of modified starch, preferably 3 to 10 wt.% of modified starch, and more preferably 3 to 5 wt.% of modified starch; 2 to 20 wt.% of waterglass, preferably 5 to 10 wt.% of waterglass, and more preferably 5 to 7 wt.% of waterglass; and 1 to 20 wt.% of aluminum hydroxide, preferably 1 to 6 wt.% of aluminum hydroxide, and more preferably 1 to 3 wt.% of aluminum hydroxide. However, other binder compositions could be used.

[0076] In a first step, the feedstock(s), in particular particulate feedstocks, are mixed with the binder(s), preferably the aqueous binder(s), to form a substantially homogeneous mixture of the particular feedstock material and the binder. In the example arrangement of FIG. 1, powdered ingredients are transported to a mixer 18, such as a double shaft mixer or any other mixer suitable for mixing particulate and liquid materials together. The powdered ingredients may be transported by any suitable mechanism. In this example, the powdered ingredients are transported from the silo(s) 12 with one or more screw conveyers 16, which may help mix the powdered ingredients. Liquid ingredients, such as the binder, preferably the aqueous binder, are dosed to the first section of the double shaft mixer 18, and the mixer 18 then mixes the (particulate) feedstock(s) and the binder(s), preferably the aqueous binder(s), such that the materials are homogenized before they enter the extruder 20. Full homogenization of the particulate feedstock with the binder is preferred for wetting all of the particles with the binder.

[0077] Many different combinations of particulate feedstock materials and binder materials can be used for the homogeneous mixture. The particulate feedstock used for the process may be only a single type of feedstock material, or the particulate feedstock may be a combination of two or more types of feedstock materials. For example, the feedstock provided for extrusion may be only one single type of feedstock, such as only wet petcoke or only petcoke fines or only titaniferous material, etc. Alternatively, the particulate feedstock provided for extrusion may include two or more different types of carbonaceous materials, two or more different types of titaniferous materials, or both carbonaceous materials and titaniferous materials. Examples of carbonaceous materials, that is, carbonaceous (particulate) feedstock materials suitable for use are described above. However, other types of carbonaceous materials could be used. Any of these carbonaceous particulate materials may have a moisture content of more than 1% and up to at least 20 wt.% (sometimes more), although lower moisture contents are more desirable. For example, petcoke fines typically have less than 10% or even less than 5% moisture contents. As an example, wet (recycled) petrol coke can be obtained from unreacted solids exhausted from a carbochlorination reactor in the same plant in its standard operation mode of making TiCk The wet (recycled) petrol coke may then be provided as at least one particulate feedstock material to be mixed and extruded. Metal oxide containing feedstock, in particular titaniferous feedstock, materials suitable for use may include any one or more of one or more of titaniferous slags, natural rutiles, synthetic rutiles, and ilmenites, and mixtures thereof; however, it is foreseeable that other titaniferous particulate materials could be used, and this list is not considered to be exhaustive. For example, titaniferous material could include titanium-bearing byproduct from the carbochlorination reactor that are too big or too small or otherwise unsuitable for TiC>2 pigment particles. Advantageously, any one or more of the particulate feedstocks may have much smaller average particle sizes (d50) than would typically be used for the carbochlorination process, even down to less than 50 pm. The particulate feedstock(s) may have average particles sizes (d50) between 20 pm to 500 pm, and even between 50 pm to 300 m. The ability to use particulate feedstocks this fine can allow the use of many more feedstocks than previously usable in the carbochlorination process and thereby significantly change the market and production processes for TiC>2 pigment particles. Similarly, any one or more of the binder materials, preferably the aqueous binder materials, mentioned herein may be used. Although the feedstock materials and the binder materials may be stored and / or transported to the mixer in almost any arrangement, it is preferred that the powder materials are stored separately from the liquid materials. Further, each different type of feedstock material and binder material is preferably stored separately from other types (e.g., each type of material is stored in a different silo 12 or 14) for ease of distribution and metering; although this is not always necessary either.

[0078] Next, the homogenized mixture is extruded using a stiff vacuum extrusion process to form an extrudate from the homogeneous mixture. The stiff vacuum extrusion is preferably conducted in a manner that provides an extrudate having a hardness, a porosity and / or density that, after later drying and sizing, will provide a suitable feedstock for a carbochlorination reaction as run in a fluidized bed reactor. To accomplish this, the vacuum extruder is run at a vacuum pressure and dynamic pressure selected to provide the needed hardness, porosity and density of extrudate. In this example configuration, the homogenized mixture is transferred from the double shaft mixer 18 to a vacuum extruder 20 by any convenient mechanism, for example by feeding directly from the mixer 18 into the extruder 20 or with any suitable conveyor mechanism. The vacuum extruder 20 is an extruder that extrudes the extrudate material under vacuum pressure, thereby implementing a stiff vacuum extrusion process on the homogenous mixture coming from the mixer 18. The stiff vacuum extrusion process may be conducted under vacuum pressures above 5 mbar, preferably between 25 and 150 mbar, and more preferably between 50 and 100 mbar. In one non-limiting arrangement, the vacuum extruder 20 is a two-stage vacuum extruder operated at relatively constant vacuum pressure between 50 mbar and 100 mbar in the second stage, although higher or lower vacuum pressures may be used. To obtain the desired hardness, density and porosity of the ultimate composite feedstock, the dynamic pressure in the second stage of the vacuum extruder 20 formed by the transport screw of the solids on the perforated disc(s) 30 at the extruder head can be controlled. The dynamic pressure from the transport screw preferably ranges between 5 bar to 100 bar, preferably from 10 bar or 20 bar to 40 bar. The density and porosity of the extrudate can also be controlled by the size and / or total area of the perforations 32 through the extruder disc 30. The extrudate diameter through the perforations 32 from the perforated disc(s) 30 preferably ranges between 4 mm and 30 mm. In some arrangements, the perforations 32 have diameters between 15 mm and 25 mm, preferably between 17 and 21 mm. In some arrangements, the perforations 32 have a diameter of 19 mm. Of course, the size of the extrudate forced through the perforations by the vacuum extruder 20 will correspond to the size of the perforations 32. The size of the perforations 32 and extrudate can be chosen to compromise between throughput of extrudate and the hardness and / or stability of the agglomerates in the extrudate. The stiff vacuum extrusion process may be conducted under temperatures between 0°C and 80°C, preferably between 30°C and 50°C, in order to provide for suitable extrudability.

[0079] Next, the raw extrudate from the extruder 20 is preferably dried and / or heat treated to a preselected, desired moisture content. Typically, the extrudate may have a moisture content from 25 wt.% to 35 wt.% when it first exits the vacuum extruder 20 through the extrusion disc 30. Preferably, this moisture is removed prior to the use of the agglomerates in the carbochlorination reactor, for example, because hydrogen atoms in the moisture (water) can form HCI in the carbochlorination reactor, which is typically not desirable because it can lead to undesirable hardness / stability of agglomerates, corrosion, and / or loss of chlorine values. Therefore, the extrudate from the vacuum extruder 20 can be dried to an acceptable moisture level that prevents or minimizes detrimental effects in the carbochlorination process. The extrudate may be actively dried by thermally treating (heat treating) the extrudate in a dryer 22 to reduce the water content of the extrudate to a desired acceptable level in order to speed up the drying process. In this example, the dryer 22 is a typical belt dryer that heats the extrudate to a temperature lower than what would cause pyrolysis of the extrudate, although other types of dryers could be used. In some embodiments, the drying is typically accomplished temperatures at low enough so as to not induce pyrolysis, which typically occurs at temperatures substantially above 300°C. Typically, the drying occurs at temperatures well below 300°C, such as less than 150°C or preferably less than 100°C. Optionally, the active drying may include using air, such as blowing air across the extrudate, to assist with the drying. However, in other embodiments, the thermal treatment may also include pyrolyzing the extrudate in addition to drying. Such pyrolyzing may include calcinating the extrudate to have a lower porosity and higher hardness than before the calcinating. For example, the thermal treatment may be conducted at temperatures substantially above 300°C so as to induce pyrolysis of the extrudate. Optionally, the thermal treatment may be conducted at temperatures above 700°C or higher, for example between 600°C and 1300°C, preferably between 700°C and 1100°C, and more preferably between 750°C and 950°C, and under exclusion of oxygen to cause calcination of the extrudate. Of course, the drying step could also be accomplished by other mechanisms, such as solely with blown air, or purely passively. In any case, for best results when later used in the carbochlorination process, the moisture in the extrudate is preferably removed during the drying step such that the extrudate to has a water content less than 1.5 wt.%, preferably less than 0.5 wt.%, and more preferably less than 0.1 wt.% to form dry extrudate.

[0080] In order for the dry extrudate to be used in the carbochlorination reactor according to the desired fluidization regime, the extrudate typically needs to be sized to have a particle size distribution (PSD) appropriate for the carbochlorination process. Typically, the extrudate is sized to have a particle size distribution between 0.1 to 10 mm (100 pm to 10000 pm), preferably 0.2 to 6 mm (200 pm to 6000 pm), more preferably between 0.3 to 5 mm (300 pm to 5000 pm), and even more preferably 0.4 to 3 mm (400 pm to 3000 pm) for best results when it is to be used as a feedstock in the carbochlorination process of making TiCL in a fluidized bed reactor, although other sizes may be used in some processes. The sizing can be accomplished by any convenient method. Typically, sizing the extrudate is accomplished after the extrudate has been dried, although in some configurations, the extrudate could be sized prior to the drying. In this example, the sizing is accomplished with a crusher 24 and a sieve 26 after the drying step in the dryer 22.

[0081] Regardless of the exact mechanisms and order used to dry and size the extrudate, the drying and sizing is preferably conducted such that the extrudate forms porous composite feedstock having a poured bulk density between 0.2 to 2.0 g / cm3, preferably 0.3 to 1.6 g / cm3, more preferably of from 0.4 and 1 .2 g / cm3, and even more preferably of from 0.8 to 1 .2 g / cm3. The porous composite feedstock can then be packaged, further processed, transported and / or used as titaniferous feedstock in a fluidized bed carbochlorination reactor 28 as part of a carbochlorination process. Advantageously, porous composite feedstock formed in this manner can have a hardness, determined by the measurement of the compression strength as specified by ASTM D4179-01 (2006), of at least 0.8 N / mm2, and preferably in the range of 0.8 to 10 N / mm2, which helps provide additional mechanical stability of the porous composite feedstock during transport, storage, and introduction into the carbochlorination reactor to prevent the particles from breaking down into particles sizes that are again too small for effective use in the carbochlorination reaction.

[0082] Following are specific test examples of porous composite feedstocks manufactured in accordance with certain principles of the present invention.

[0083] EXAMPLE SECTION

[0084] Measurement methods Poured bulk density measurement

[0085] The poured bulk density is determined by the ratio of the mass to a given volume. For the determination, the substance is put into a receiver of known dimensions and weight. The apparatus used for determination of the poured bulk density is SMG 697 provided by Powtec Maschinen und Engineering GmbH (Remscheid, Germany).

[0086] The International Standard ISO 697 describes the procedure of the determination of density and the tools required. The International Standard ISO 697 distinguishes two types for the determination of apparent bulk density. They basically differ in the size of the receivers used. Type SMG 697 fulfils the conditions indicated in ISO 697 and is delivered with a 500 ml receiver. The instruments for the determination of density imply a lockable funnel of fixed dimensions, a receiver and a stand that holds them together in a defined position. The funnel is then filled with the sample of powder or granule then opened. The sample then flows into the receiver with the known volume and the density is obtained by weighing the receiver. In case of powders containing lumps, the method is applicable only if these can be disintegrated readily without breaking down the particles of the powder. The sieve fraction between 500 pm and 2000 pm was used for measuring the density of the material (after comminution).

[0087] BET determination

[0088] Determination of the volume-specific surface area of solids by low-temperature nitrogen adsorption measurement method according to Brunauer, Emmet and Teller as specified by ISO 9277.

[0089] The device TriStar II - Micromeritics works according to the classic, static volumetric principle. After the basic preparation of the sample, a corresponding sample quantity displaying an equivalent of approx. 10m2 / g BET surface is placed into the measuring cell and brought to a target measurement temperature of 77 Kelvin. A defined quantity of gas from a known gas volume container is introduced into the sample chamber and the prevailing equilibrium pressure is measured. The amount of the adsorbed gas is calculated from the volumes and pressures measured before and after adsorption. The surface area coverage and the equilibrium pressure are increased by gradually adding the gas amount, whereas 3 to 7, preferably 5 measurement points are taken into account for the evaluation. The value for the volume-specific surface area is determined by mathematical processing of the data. The measurements are validated against Silica-Alumina standard sample with known BET. Determination of the material hardness by the measurement of the compression strength as specified by ASTM D4179-01 (2006)

[0090] The device DARTO PM 10 works according to the mechanical principle, where the force at the breakage point is measured on the pellet sample, when a pellet sample is placed between two metal plates, which are compressed at a fixed strain rate while force and distance are recorded in form of compression curves. The pellet hardness is expressed in [N / mm2] as the maximum compression strength required to crush the pellet of given length. The procedure is replicated from 3 to 10 times, preferably 5 times, and the average of all measurements taken is determined.

[0091] Determination of the pore volume and pore size distribution of solids by low-temperature nitrogen adsorption measurement method according to Barrett, Joyner, and Halenda as specified by DIN 66134.

[0092] The device TriStar II - Micromeritics works according to the classic, static volumetric principle. After the basic preparation of the sample, a corresponding sample quantity displaying an equivalent of approx. 10m2 / g BET surface is placed into the measuring cell and brought to a target measurement temperature of 77 Kelvin. A defined quantity of gas from a known gas volume container is introduced into the sample chamber and the prevailing equilibrium pressure is measured. The amount of the adsorbed gas is calculated from the volumes and pressures measured before and after adsorption as well as before and after desorption. Complete adsorption and desorption isotherms are determined according to this procedure, whereas 40 to 60, preferably 50, measurement points are taken into account for each isotherm. The pore volume and the pore size distribution are obtained by mathematical processing of the data, using Kelvin equation. The measurements are validated against Silica-Alumina standard sample with known pore diameter, pore volume and pore size distribution.

[0093] Determination of the pore diameter, pore volume and pore size distribution by Hg-intrusion and extrusion measurement as specified by ISO 15901-1 and DIN 66133

[0094] The devices Belpore HP - Microtrac or Quantachrome PoreMaster 60 - Anton Paar work according to the physical principle where a non-reactive, non-wetting fluids like mercury penetrates fine pores at sufficient pressures applied to allow the intrusion of the sample. After the preparation of the sample, it is introduced into the sample cell called a penetrometer. The cell is evacuated, and backfilled with mercury. For the measurements of larger pores gas pressure of up to 3,45 bar is applied upon the sample pneumatically. For measurements of smaller pores, liquid pressure of up to 4140 bar is applied upon the sample hydraulically. After the quantification of the mercury amount intruded into pores in each pressurization event (pneumatic and hydraulic), the pressure is then decreased to ambient atmospheric pressure. The depressurization event results in retraction of the mercury, i.e. extrusion from the pores. The pore diameter, pore volume and the pore size distribution are obtained by mathematical processing of the pressure dependent intrusion and extrusion volume data, using the Washburn equation.

[0095] Example 1 :

[0096] 2000 kg / h of wet recycled petrol coke having a moisture content of 38 wt.% were premixed with 700 kg / h of dried fine petrol coke having a moisture content of less than 0.5 wt.%, which resulted in a mixture of wet recycled petrol coke and dried petrol coke having moisture of 28 wt.%. To this mixture, modified starch dry powder was added at a rate of 140 kg / h and mixed to form a homogeneous mixture of the wet recycled petrol coke, dried petrol coke, and modified starch powder. The homogeneous mixture was transferred to and extruded through the vacuum extrusion machine (J.C Steele & Sons HD-10 extrusion system) operated at a dynamic pressure of 7 bar, a vacuum of 40 mbar, and a screw speed of 20 rpm resulting in torque of 83 Nm using a perforated disc with individual hole openings with diameters of 19 mm. The extrudate was then dried at 80°C in a belt dryer to achieve a moisture content below 0.5 wt.%. The dried extrudate was then sized by crushing and sieving to obtain agglomerated particles of the porous composite particulate feedstock having sizes between 1 mm to 3 mm. The oversize and undersize (less than 1 mm and greater than 3 mm) agglomerated particles were returned to the beginning of the process as 700 kg / h stream for reusing in another round of forming porous composite feedstocks. The final agglomerated and dry porous composite particulate feedstock contained 7.3 wt.% of starch, as measured relative to the contents of the porous composite feedstock after the drying.

[0097] Example 2:

[0098] 1850 kg / h of wet recycled petrol coke having a moisture content of 38 wt.% were premixed with 650 kg / h of dried fine petrol coke having a moisture content of less than 0.5 wt.%, which resulted in a mixture of wet recycled petrol coke and dried petrol coke having moisture of 28 wt.%. To this mixture, dry modified starch powder was added at a rate of 130 kg / h, and 220 kg / h of waterglass was added as an aqueous formulation with 44.5% of active ingredient, and the entire mixture was mixed to form a homogeneous mixture of the wet recycled petrol coke, dried petrol coke, modified starch powder, and water glass. The homogeneous mixture was transferred to and extruded through the vacuum extrusion machine operated at a dynamic pressure of 19 bar, a vacuum of 30 mbar, and a screw speed of 20 rpm resulting in torque of 150 Nm using a perforated disc with individual hole openings having diameters of 19 mm. Extrudate was then dried at 80°C in a belt dryer to achieve a moisture content below 0.5 wt.%. The dried extrudate was then sized by crushing and sieving to obtain agglomerated particles of the porous composite particulate feedstock having sizes between 1 mm to 3 mm. The oversize and undersize (less than 1 mm and greater than 3 mm) agglomerate particles were returned to the beginning of the process as 650 kg / h stream for reusing in another round of forming porous composite feedstocks. The final agglomerated and dry porous composite particulate feedstock contained 7.3 wt.% of starch and 12 wt.% of waterglass, as measured relative to the contents of the porous composite feedstock after the drying.

[0099] Example 3:

[0100] 1800 kg / h of wet recycled petrol coke having a moisture content of 38 wt.% was premixed with 600 kg / h of dried fine petrol coke having a moisture content of below 0.5 wt.%, which resulted in a mixture having moisture of 28 wt.%. To this mixture, dry modified starch powder was added at a rate of 125 kg / h, 210 kg / h of water glass was added as an aqueous formulation with 44.5% of active ingredient, and 80 kg / h of aluminum hydroxide powder was added, and the entire mixture was mixed to form a homogeneous mixture of the wet recycled petrol coke, dried petrol coke, modified starch powder, water glass, and aluminum hydroxide powder. The homogeneous mixture was transferred to and extruded through the vacuum extrusion machine operated at a dynamic pressure of 29 bar, a vacuum of 25 mbar, and a screw speed of 8 rpm resulting in torque of 250 Nm using a perforated disc with individual hole openings having diameters of 19 mm. The extrudate was then dried at 80°C in a belt dryer to achieve a moisture content below 0.5 wt.%. The dried extrudate was then sized by crushing and sieving to obtain agglomerated particles of the porous composite particulate feedstock having sizes between 1 mm to 3 mm. The oversize and undersize (less than 1 mm and greater than 3 mm) agglomerated particles were returned to the beginning of the process as 650 kg / h stream for reusing in another round of forming porous composite feedstocks. The final agglomerated and dry porous composite particulate feedstock contained 7.3 wt.% of starch, 12 wt.% of water glass, and 5 wt.% of aluminum hydroxide, as measured relative to the contents of the porous composite feedstock after the drying. Following the general process described above for examples 1 to 3, other formulations of porous composite feedstocks with the following materials and properties listed in Table 1 below were obtained.

[0101] Table 1 : Porous composite feedstock formulations

[0102] Example 4:

[0103] 1000 kg of wet petcoke having a moisture content of between 30-40 wt.% is pre-mixed with 50 kg modified starch powder. To this pre-mixture, 70 kg of liquid waterglass is added as an aqueous formulation, and the entire mixture is mixed in a double shaft mixer to form a homogeneous mixture of the wet recycled petcoke, modified starch powder, and water glass such that substantially all of the petcoke particles are wetted with the binder (waterglass and modified starch powder). Next, the homogeneous mixture is transferred to and extruded through the vacuum extrusion machine operated at a dynamic pressure from the extrusion screw of 10-40 bar and a vacuum of 50-100 mbar, using a perforated disc with individual hole openings having diameters of 19 mm. To reduce the moisture content of the extrudate to a more desirable level for use in the carbochlorination process, the extrudate is then dried in a belt dryer to achieve a moisture content below 1.0 wt.% relative to the total mass of the dried extrudate. The dried extrudate is then sized to a more suitable size for use in the carbochlorination process by crushing and sieving the dried extrudate to obtain agglomerated particles of the porous composite particulate feedstock having sizes between about 500 pm to 5000 pm (0.5 to 5 mm).

[0104] FIG. 3 obtained by light microscopy shows a sample of the porous composite feedstock obtained in Example 4.

[0105] The porous composite feedstock according to the invention is suitable for use in the carbochlorination process of making TiCk In use, the porous composite feedstock may be supplied into the fluidized bed reactor during the carbochlorination process of making TiCU in a fluidized bed reactor in any suitable manner, such as through one or more pipes or other inlets into the fluidized bed reactor before and / or during the carbochlorination reaction process.

[0106] Above examples demonstrate a porous composite feedstock according to the present invention suitable for carbochlorination processes and can therefore be used as sources of feedstock for use in e.g. making TiC>2 pigment particles.

Claims

CLAIMS1. A porous composite feedstock for metal chloride preparation, comprising a metal oxide containing material, preferably a titaniferous material, more preferably a first titaniferous material; and / or a first additive, preferably a first carbonaceous material; and a binder, preferably a binder composition; wherein the porous composite feedstock is in particulate form; wherein the water content of the porous composite feedstock is in the range of from 0.01 to 5 wt.% based on the weight of the porous composite feedstock; and wherein the porous composite feedstock has a poured bulk density in the range of from 0.2 g / cm3and 2.0 g / cm3.

2. Porous composite feedstock according to claim 1, wherein the porous composite feedstock comprises a second titaniferous material, wherein the second titaniferous material is different from a first titaniferous material; and / or a second additive, wherein the second additive is different from the first additive, preferably the second additive is a second carbonaceous material.

3. Porous composite feedstock according to any of the preceding claims, wherein the porous composite feedstock has a particle size distribution (PSD) in the range of from 0.1 mm to 10 mm, preferably of from 0.2 mm to 6 mm, more preferably of from 0.3 mm to 5 mm and even more preferably of from 0.4 to 3 mm; and / or wherein the titaniferous material has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm; and / or wherein the first titaniferous material has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm; and / orwherein the second titaniferous material has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm; and / or wherein the first additive has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm; and / or wherein the second additive has a particle size distribution (PSD) in the range of from 10 pm to 500 pm, preferably of from 25 pm to 400 pm, and more preferably of from 50 pm to 300 pm.

4. Composite feedstock according to any of the preceding claims, wherein the porous composite feedstock has a poured bulk density in the range of from 0.3 to 1.6 g / cm3, more preferably of from 0.4 and 1.2 g / cm3, and even more preferably of from 0.5 to 0.9 g / cm3; and / or wherein the porous composite feedstock has a hardness of at least 0.8 N / mm2, preferably at least 0.9 N / mm2, more preferably at least 1.4 N / mm2, and even more preferably of at least 2.0 N / mm2; and / or wherein the porous composite feedstock has a porosity, as measured by mercury intrusion and extrusion measurement method, of 10 to 90%, preferably of 20 to 80% and more preferably of 30 to 70%; and / or wherein the porous composite feedstock has a porosity, as measured by the low- temperature nitrogen adsorption measurement method according to Barrett, Joyner, and Halenda, of 10 to 90%, preferably of 20 to 80% and more preferably of 30 to 70%; and / or wherein the porous composite feedstock has a BET value of more than 10 m2 / g, preferably more than 100 m2 / g, and even more preferably more than 200 m2 / g, and preferably not exceeding 2000 m2 / g.

5. Porous composite feedstock according to any of the preceding claims, wherein the first additive is porous, preferably the first carbonaceous material is porous; and / or wherein the first carbonaceous material is selected from the group consisting of coke, petroleum coke, fine petroleum coke, wet petroleum coke, recycled petroleum coke,wet recycled petroleum coke, biocoke, carbon containing slag fines, charcoal, green petrol coke fines, calcined petroleum coke, gilsonite, anthracite coal, pyrolysis coke, hydrothermal carbon (HTC), biochar and combinations thereof; and / or wherein the amount of first carbonaceous material in the porous composite feedstock is in the range of from 0 to 95 wt.%, preferably of from 10 to 90 wt.%, and more preferably of from 10 to 60 wt.% based on the weight of the composite feedstock; and / or wherein the first titaniferous material is selected from the group consisting of titaniferous slag, rutile, synthetic rutile, ilmenite and combinations thereof.

6. Porous composite feedstock according to claims 2 to 5, wherein the second additive is porous, preferably the second carbonaceous material is porous; and / or wherein the second carbonaceous material is selected from the group consisting of coke, petroleum coke, fine petroleum coke, wet petroleum coke, recycled petroleum coke, wet recycled petroleum coke, biocoke, carbon containing slag fines, charcoal, green petrol coke fines, calcined petroleum coke, gilsonite, anthracite coal, pyrolysis coke, hydrothermal carbon (HTC), biochar and combinations thereof; and / or wherein the second titaniferous material is selected from the group consisting of titaniferous slag, rutile, synthetic rutile, ilmenite and combinations thereof.

7. Porous composite feedstock according to any of the preceding claims, wherein the water content of the porous composite feedstock is in the range of from 0.01 to 4 wt.%, preferably of from 0.02 to 2 wt.%, more preferably of from 0.03 to 1 wt.%, and even more preferably of from 0.04 to 0.5 wt.% based on the weight of the composite feedstock; and / or wherein the content of volatile compounds comprising hydrogen and oxygen other than water is less than 1 wt.%, and preferably less than 0.5 wt.% based on the weight of the composite feedstock; and / or wherein the content of volatile compounds comprising hydrogen and oxygen other than water is in the range of from 0.01 to 2 wt.%, preferably of from 0.02 to 1 wt.%, preferably of from 0.03 to 0.5 wt.% based on the weight of the composite feedstock.

8. Porous composite feedstock according to any of the preceding claims, wherein the binder is an aqueous binder; and / or wherein the binder is selected from the group consisting of lignosulfonate, carbohydrates, polyvinyl alcohol, water-based plasticizers, tannins, lignin, inorganic binders and combinations thereof; or wherein the binder is selected from the group consisting of lignosulfonate, glycerin, saccharides, molasses, starch, modified starch, cellulose, including carboxymethyl cellulose (CMC), lignocellulose, functionalized lignocellulose, lignin, polyvinyl alcohol, water-based plasticizers, tannins, cement, bentonite, waterglass, aluminum hydroxide, metakaolin, clay, carbon black, and combinations thereof.

9. Porous composite feedstock according to any of the preceding claims, wherein the amount of binder is in the range of from 0.5 to 25 wt.%, preferably of from 1 to 20 wt.%, more preferably of from 2 to 10 wt.% and even more preferably of from 2 to 5 wt.% based on the weight of the porous composite feedstock.

10. Porous composite feedstock according to any of the preceding claims, wherein the binder comprises more than 20 wt.%, preferably more than 35 wt.%, more preferably more than 50 wt.%, and even more preferably 20 to 75 wt.% of waterglass based on the weight of the binder; and / or wherein the binder comprises more than 20 wt.%, preferably more than 35 wt.%, more preferably more than 50 wt.%, and even more preferably 20 to 75 wt.% of starch or modified starch based on the weight of the binder.

11. Porous composite feedstock according to any of the preceding claims, wherein the porous composite feedstock comprises 2 to 20 wt.%, preferably 3 to 12 wt.%, and more preferably 5 to 10 wt.% of starch or modified starch based on the weight of the composite feedstock; and / or wherein the porous composite feedstock comprises 2 to 20 wt.%, preferably 3 to 12 wt.%, and more preferably 5 to 10 wt.% of waterglass based on the weight of the composite feedstock.

12. Porous composite feedstock according to any of the preceding claims, wherein the second additive is a non-carbonaceous material, preferably a non- carbonaceous porous material, and more preferably selected from the group consisting of porous inorganic material, porous mineral, bentonite, diatomite, zeolite, volcanic tuffs, porous carbides, pumice, and combinations thereof.

13. Use of a porous composite feedstock according to claims 1 to 12 in the preparation of metal chloride, preferably TiCk, in a carbochlorination process, preferably in a carbochlorination process in a fluidized bed reactor.

14. Use of a porous composite feedstock in the preparation of a metal chloride according to claim 13, wherein the porous composite feedstock is added to the fluidized bed reactor during the carbochlorination process.

15. Use of the porous composite feedstock according to claims 1 to 12 as fluidized bed stabilizer in the preparation of a metal chloride, preferably TiCk.

16. Method for preparing metal chloride, preferably TiCk, comprising the steps of adding a solid feedstock comprising alkaline earth metal salts and alkaline earth metal oxides to a reaction vessel, preferably to a fluidized bed reactor; adding the porous composite feedstock according to claims 1 to 13 to the reaction vessel, wherein the composite feedstock may be added before or after the solid feedstock. mixing the solid feedstock and the porous composite feedstock forming a reaction mixture.

17. Method according to claim 16, wherein the method is a carbochlorination process.

18. Method according to claims 16 or 17, comprising the further step ofremoving alkaline earth metal salts, preferably alkaline earth metal chlorides, more preferably MgCh and CaCh, from the reaction mixture in the reaction vessel, preferably discharging disintegrated porous composite feedstock particles loaded with alkaline earth metal salts, preferably alkaline earth metal chlorides, more preferably MgCh and CaCh, from the reaction vessel.