JPH04500984A - Sintered high titanium-containing agglomerates - Google Patents

Abstract

A process for increasing the particle size of fines of a titaniferous mineral containing more than 45 % by weight of titanium. The process comprises mixing the fines with a binding agent and water to produce an agglomerate. The agglomerate is then dried and sintered.

Description

[Detailed description of the invention] Sintered high titanium-containing agglomerates The present invention provides titanium-containing materials suitable for forming TIC14. +ring) relating to aggregates of substances.

In the conventional method, substances with a high titanium dioxide content (T10285% or more) are , according to the specification regarding the particle size and content of impurity elements of the substance, TiCl4 is It is a preferred raw material for manufacturing.

TlC14 is a low-boiling liquid that is purified by distillation and chemical methods. can be combusted in oxygen to generate TlO2 pigment and chlorine gas, or react with magnesium or electrolyze to form metallic titanium. be able to.

The raw material, i.e., titanium-containing mineral with a size of 100 to 300 μm, is subjected to a fluidized bed reaction. where it undergoes reductive chlorination at a temperature range of 900-1000°C. Ru. Petroleum coke or similar highly fixed carbon material is added to the bed as fuel and reducing material. Add as both agents. Oxygen may be added to the inlet to maintain the reaction temperature.

The TiCl4 product is entrained from the impurity elemental gaseous chloride and the fluidized bed. It leaves the reactor in gaseous form together with the finely divided solid particles. This gas is solid Body bones are removed and condensed. The TlCl4 product is subjected to distillation and chemical methods. Therefore, it is purified.

In the chlorination step, most metal impurities form volatile chlorides and TlCl 4 exits the reactor in a gas stream. However, alkali metals and alkali Lithium metals form relatively less volatile chlorides that are liquid at the reaction temperature; This prevents the formation of agglomerates in the bed until a possible shutdown occurs. There is a tendency to Therefore, operators of the process usually There are strict limits on quantity.

Impurities such as iron are even more important in that they consume coke due to their reduction. Importantly, it consumes expensive chlorine reagents that are lost in iron chloride waste. This brings about economic disadvantages in the method. Also silicon and aluminum The chlorine is also partially chlorinated in the process, resulting in excessive chlorine depletion. Also, acetic acid chloride Luminium is a source of corrosion in equipment used in this method.

As mineral particles become progressively chlorinated, their size decreases as they become entrained in airflow. of the reactor, leaving the reactor as unavoidable and irrecoverable losses. Ku. Conventionally, the loss due to the entrainment is 5 to 10% of the total mineral input.

When the diameter of the supplied particles is reduced to less than 150 μm, the entrainment loss rate is Relatively expensive than normal shaped materials. Such losses reduce economic and operational efficiency. Either is not acceptable.

In an attempt to overcome these problems, methods known in the prior art include TlO2- The mixture of containing materials, bituminous coal, and water-soluble paint is coked to form particulates. Particulate TiO2-containing material can be prepared for fluidized bed chlorination by forming an agglomerated composite. Preparing a substance. However, this prior art method is industrially unsatisfactory. It's not something you can do. One reason is that the chlorination method is reductive chlorination. Therefore, the carbon in the feed material is not present in a specific ratio to the TlO2-containing material. This is because this is not suitable for developing the strength of the composite. Change The resulting agglomerates are attacked before they are completely chlorinated because their carbon is attacked. material of fairly fine particle size is entrained in the air flow and lost during the process.

Other methods described in the prior art involve extruding pellets of particulate titanium-containing material. an aqueous emulsion of asphalt as a binder when formed by I am using it.

A slow curing process at 1000°C removes water from the pellet. organic matter is converted to carbon. As a result of this hardening process, Solidification of the binder occurs at the edges, forming a strong bond. the binder No chemical bond is formed between the titanium-containing material and the titanium-containing substance. This extruded material is hard The product must be collapsed to a size range close to that of the product being prepared. do not have. Thus, in order to reduce the strength of the product pellet in another way, the hardened The need for circulating particulate matter is eliminated. During the chlorination of the pellet, this carbon , contributes to the reductive chlorination process.

Therefore, this product has similar disadvantages as those described in previous prior art examples. Ru.

It is an object of the present invention to solve the problems observed in fluidized bed chlorination of particulate titanium-containing materials. The goal is to overcome the above.

Therefore, the present invention provides a titanium iron (II) mineral containing 45% by weight or more of titanium. A method for increasing the particle size of a fine powder, the fine powder being mixed with a binder and water to coagulate. forming an agglomerate, drying the agglomerate, and sintering the agglomerate. Provided is a method for providing and.

The agglomerated particles formed are resistant to decomposition forces associated with transportation and handling. be. The agglomerated particles are also associated with chlorination methods, including fluidized bed reductive chlorination methods. It is also resistant to physical decomposition forces, chemical decomposition forces, and temperatures.

The agglomerated particles are of a preferred type adapted to the kinetic requirements of the fluidized bed reductive chlorination process. Can be manufactured in a wide range of sizes. This size range is, for example, 100 to 500 μm1 is more preferably about 150 to 250 μm. If the particles exceed the above range, Below this, these particles are lost during the reaction as they become entrained in the air flow. If the particle is Above this range, these particles will float in the fluidized bed, leaving an inert layer at the bottom of the reactor. layers are formed.

The titanium-containing particles may be any suitable titanium-containing mineral or group of minerals. There may be. The titanium-containing mineral may be natural or synthetic. You can. The titanium-containing mineral may be a detrital mineral. Titanium is Exists in the form of titanium dioxide in titanium-containing minerals. Dioxide in titanium-containing minerals The titanium content can be about 85% by weight or more. Preferred titanium dioxide-containing materials The source is a sediment containing any of the minerals rutile, anatase, and leucoxin. It is a product.

The titanium-containing mineral may be subjected to an initial concentration treatment after extraction.

The initial concentration treatment increases the average content of titanium dioxide to, for example, about 90% by weight or more. You can make it bigger.

One of this type of titanium-containing mineral, Horsi, Victoria, Australia. The titanium-bearing mineral deposits from Horsham were further processed by conventional pulverization. Characteristics can be added by doing this. Unusual refinement is due to concomitant losses. It is suggested that the majority arises from post-treatment by reductive chlorination in the fluidized bed.

The titanium-containing mineral may be present in an appropriate amount in the agglomerated particles.

The titanium-containing mineral has a titanium-containing mineral content of about 95 to 99%, based on the total weight of the sintered agglomerate. May be present at 5% by weight.

The amount of water added depends on the size distribution of the original titanium-containing particles and the required aggregate size. may vary depending on the situation. The amount of water is the total amount of titanium-containing particles, binder, and water. Varies between about 5 and 15% by weight, preferably about 8% by weight. .

The binder or binders for the titanium-containing particles can be of a suitable type. It can be anything. The binder for the titanium-containing particles is resistance to physical, chemical, and thermal decomposition forces during drying and combustion processes. It must be such that it forms aggregates that can be resisted. The binder is , may be organic or inorganic, and may be a ceramic or glass forming binder. It may be under. Even if the binder is a carbon-free binder, good. A type of binder may also be used. Combining two or more types of binders It is used in combination to provide strength under different operating conditions of the drying and combustion steps. You can also give.

Binders containing calcium or sodium are not preferred. This is applicable Calcium or sodium components in the binder undergo the reductive chlorination process. This is due to the fact that it reacts with water and forms a toxic liquid residue. The binder is calciu chlorinated by the addition of these elements. No problems should arise.

Binders for titanium-containing minerals can be removed by subsequent processes, e.g. reductive chlorination. such that it does not seriously contaminate the bound titanium-containing particles for Probably.

The binder for the titanium-containing particles may include the following compounds 1) to 15). Ru: 1) Colloidal silica 2) Silica, water-soluble silicates, or silica/fluorspar mixtures 3) Clay minerals (including bentonite, kaolinite, and montmorillonite) 4) Boehmite 5) Boehmite/silica mixture 6) Geosite (GrofhNe) 7) Lignosulfonate 8) Sodium carbonate (saturated aqueous solution) 9) Sodium silicate 10) Group ■ element carbonate/clay mineral mixture 11) Sugars such as molasses 12) Aluminum salt/organic amide mixture 13) Organic solution containing titanium and and inorganic solution 14) Polyvinyl acetate 15) Organic binder emulsified with water.

The amount of binder to the titanium-containing particles is sufficient to form an effective agglomerate. It must be a sufficient amount. The amount of binder preferably includes titanium-containing particles. There should not be enough to envelop. The binder should have a relatively low percentage is preferred. Preferably, this ratio ranges from about 0.5 to 5% by weight.

The mixing step in the method of the invention can be done by any suitable method. agglomeration is a rotating disc or drum pelletizer or a V-blender. equipment that incorporates rolling/fumbling motions such as In a high-strength micro-agglomerator (agglomer! to, r) or mixer In devices that incorporate impact/shear actions such as This can be done in a standard equipment. A process that uses a screen to size the product It may be aggregated in a closed circuit or in a closed circuit.

The drying step can be carried out by increasing the temperature, for example from 75°C to 150°C. . The drying step has a residence time of 30 minutes for the aggregates at this step in the process. Preferably, it is carried out by a method that is limited to less than or equal to. The drying process Any suitable drying equipment may be used. Fluid bed dryer or rotary dryer You may also use a machine.

In the combustion process, the temperature and residence time are controlled to create an even bond between the particles in the agglomerate. It must be sufficient to form a single phase or a heterogeneous phase. The aggregate has a temperature It may be heated to about 1000-1500°C, preferably 1200-1400°C.

The residence time of the agglomerates within the temperature range may be about 5 minutes to 6 hours.

The combustion process can be performed in a number of ways, including fluidized bed, oven, or kiln combustion. This may be done by any suitable means.

In a preferred form of the invention, the process includes at least one titanium-containing particle species. A preliminary step of crushing a portion may also be included.

The pre-grinding step allows for improved size control in agglomerate preparation and Greater strength and density can be imparted to the baked product. The chi Tan particles may be introduced into any suitable grinder. ball mill, rod mill, ma or high-intensity grinding equipment may be used.

The amount of titanium-containing raw material to be crushed depends on the type or type of titanium-containing material. The weight ratio varies from 0 to about 100% by weight.

The milling step may provide particles having an average size of about 1 μm to about 50 μm. .

A sintered agglomerate may include a large number of sintered agglomerate particles. Between titanium-containing particles The bonds formed are due to grain boundary recrystallization, i.e., the boundaries of the titanium-containing grains physically fuse together. may include doing. The bonds formed between the titanium-containing particles further include a binder. crosslinking by a second phase formed by -. The sintering step There may be a tendency to reduce or remove binder from the aggregate particles. early buy The powder can be largely or partially burned off. The initial binder is added to the grains. present and/or incorporated into a major part or part of the crystal lattice in the child It's okay.

The invention will be explained in more detail with reference to the following examples. However, the following statement is merely illustrative of the invention and is not intended to limit the general outline of the invention described above.

Example 1 First, a laboratory-scale batch batch Baderlin-Kelly (Palterson-Keley) lly) Using a V-blender, mix dry powder with 1% dry bentonite powder. The mixture of 9.2 kg of dried leucoxin was blended for 1-2 minutes. The leucoxin is 75% in the size range 50-100 μm, and 75% in the size range ~50 μm. It consisted of 25% portion. The size distribution of the three parts is listed in Tables 1 and 2. Record.

Table 1 Size distribution of milled and sized leucoxin (~100+50μm) Size (μm) Cumulative % 106 95, 0 Size distribution size (μm) of ~50μm portion of crushed leucoxin Cumulative % 106 100, 0 38 90, 4 33 88, 6 50.0 The V-blender was rotated at a speed of 4 Qrpm. Next, blender the mixture at 1500-3000 rpm.

Water is introduced through a reinforcing bar (injCnsifier b+r) that rotates with Ta. This reinforcing bar has a shearing effect on the solid and the final divided shape. It had the effect of spraying water onto the filling. Added water is approximately 8% of solid weight The time required for this addition was about 4 minutes. Furthermore, when mixing for 1 to 2 minutes Depending on the time, microagglomerates will have a smaller final size. and made it possible to achieve compression.

The product is then poured onto a large tray, spread out and oven heated at 80°C for 48 hours. Dry and ensure drying is complete. A sample of 100g of this fine aggregate was The mixture was placed on a dish and heated at 1260° C. for 25 minutes. Next, this grilled The resulting product is subjected to a number of physical and chemical tests as may be considered appropriate. Therefore, its suitability as a feedstock for reductive chlorination was determined.

Visual inspection of the microagglomerates after sintering showed that they were significantly smaller than the dried but unsintered material. Two obvious changes were observed.

First, shrinkage in the internal voids of the microagglomerates or the grain size of the agglomerates during sintering This means that shrinkage occurs due to either a reduction in the intercellular void. Secondly, The color of the substance changed from grayish brown to reddish brown. Change The material has a glassy or reflective surface compared to the cloudy surface of the unfired material. It represented a sexual state.

When the sintered product was examined under a microscope, it was found that the sintered product was microscopic with abundant cross-links between the particles. It was shown that the particles were tightly packed within the aggregates. electronic microscope analysis showed that there was no structural difference between the cross-linked material and the particles. . No visible decomposition or agglomerate-agglomerate adhesion was observed as a result of firing. It wasn't done. In the X-ray diffraction analysis of the calcined microaggregates, mainly rutile phase and pseudo-Brutskite phase, i.e., concretions that can be formed only from the original leucoxin. A crystalline phase was shown.

The size of the product after calcination is shown in Table 3.

Table 3 ~110+50μm, 75% and ~50μm, 25% of the feed material Agglomerated with 1% tonite binder and fired at 1260°C for 25 minutes. The sintered leucoxin product obtained by “Strength test) (slrenglh!esj)” is about the microagglomerates. It was carried out as follows; the microagglomerates were placed between two glass slides, and the microagglomerates were placed between two glass slides. A load was applied until the object first broke. The first failure occurred when the load was 1 kg (i.e. 1 ON), 300 μm aggregates occurred. Destruction fragments are of uniform size. ie, there was little or no tendency to dust. In the calculation, Because of this recorded strength, the agglomerates were found in piles and storage bins approximately 50 m high. It has been shown that it can be stored without being destroyed even under compressive force.

A more quantitative and reproducible test to evaluate resistance to abrasion. went. This test consists of fragments of microagglomerates of almost the same size (250-335 μm). 1g piece, inner diameter 18+*m.

In a cylindrical tube with a length of 5 bm and 3 ceramic balls of diameter 8++ m This was done by shaking vigorously for 5 minutes. During this test, the substance Subject to both impact and abrasion. The average particle size after testing is from 303μm to 170μm It decreased to m. This means that a similar sample of the original leucoxin was 220 This is in contrast to the fact that it has become as small as μm.

We conclude that the microagglomerates are industrially useful materials in terms of storage and transportation. be able to.

A small sample (10 g) of microaggregates was prepared in a laboratory at a temperature of 950 to 1100°C. Fluidized bed chlorination tests were conducted in a scale reactor. As a result, completion of chlorination was 5 When it exceeded 0%, the following was shown: (1) There was no sign of preferential attack on interparticle bonds.

Rather, this bond appeared to be relatively inert compared to the main mass of each mineral grain.

(2) The original state (color An unreacted core of material (apart from bare bleaching) remained inside the microagglomerates.

The affected outer shell pores increased significantly in size.

Table 4 shows the combusted aggregates before and after chlorination in laboratory fluidized bed tests. and the size distribution after 89% completion of chlorination. clearly,~ Substances with a diameter of 90 μm are hardly generated due to chlorination, and are caused by decomposition of bonds or discharge. In the absence of losses from the reactor such as fines carried in the gas, a high degree of chlorination is possible. It has been shown that this can be achieved. Even if it is completed to 95%, the same result will be obtained. can get.

Temperature 1090℃ Time 70 minutes Chlorine flow rate 10100O/min Calculated gas velocity in the bed Oj5m/sec Bed height lfbem Supply weight: 10g Floor residue 0.9g Carryover 0.25g Chlorination rate: 88.5% Size range Feed material Terminal acid (μm) g% g% +425 0.64 6.4 - - -425+355 3.24 32.4 - -355+300 3.25 32.5 0.10 11.1-300+250 2.16 21.6 0.1 6 17.8-250+180 0j3 3j O, 2932, 0-180+9 0 0j7 3.7 0j5 38.9 The fluidization performance of the fine aggregates depends on their size. of theoretical sphere, petroleum coke, and gravelly leucoxin. compared to behavior. This result is compared to the average particle size in room-temperature air. Pro soto as the minimum fluidization speed and shown in Fig. 1. These results are higher than the expected minimum fluidization velocity for smaller particle sizes and higher than expected for larger particle sizes. This indicates that the fluidization rate is lower than the expected minimum fluidization rate.

This behavior is partly due to size distribution effects and partly due to concentration, surface It can be explained by shape and roughness effects. The chlorination process is Agglomerate particles that are much larger than those in the feedstock can also be accepted. and make it possible to improve the recovery rate of the process.

Example 2 Approximately 10 g of ground leucoxin was agglomerated and dried as described in Example 1.

This microagglomerate was fed to a small experimental scale fluidized bed furnace, and the bed temperature was maintained at 1260°C. . The operating parameters of the furnace were as follows: Floor diameter 30cm Wind box warm!　1000℃ Wind box fuel LPG Fuel on the floor next to coconut shells Surface gas velocity 71cm sec’ Aggregate feeding rate 22 kghr-' In order to control both the temperature and the surface gas flow rate inside the bed within the desired range. Therefore, enrichment with inert gas along with oxygen is necessary on this small device. It was discovered that

The average residence time of the material inside the bed was approximately 20 minutes.

The amount of body material lost by entrainment in the expelled gas is estimated to be 4.5%. Ta. The size distributions of feedstock, product, and carryover material are shown in Fig. 2 Shown below.

This product was subjected to the friction-friction test described in Example 1. As a result, the average grain It was shown that the diameter decreased from 303 μm to 190 μm.

Example 3 Agglomeration tests were conducted on samples of rutile powder with the following size distribution: : Table 5 Size distribution of rutile powder The flocculation was carried out by Sbu, gi, Process Engineers (Netherlands). Using a "Flexomix" flocculator manufactured by Lelystad, The solid feed rate was 840 kg/hour. Adding bentonite to the feedstock at 1% 33% of 2.8 kg of solid bone per hour. Added as a solution. In addition to the addition of lignosulfonate, the moisture was reduced to lΩmin, −'I invested it.

After continuous passage through the agglomerator and fluidized bed, the product has a dry unit of 67.5% The size range was 125 to 500 μm.

The product coarser than 125 μm in diameter was collected in a kiln for subsequent calcination.

The calcination of the agglomerates was carried out using a 3.6 m long, 0.23 m internal diameter combustion cycle with backflow oil. It was done in a rotating kiln. At a rotation speed of 2 rpm, and an inclination of 1", a high temperature of 1260 °C The residence time of the aggregates in the warm region was about 20 minutes. Inside this kiln , a total of 4160 kg of agglomerate was calcined at a feed rate of 16.2 kg per hour.

Combustion gases remove fines in the feedstock and decomposition products formed during combustion. When removed from the kiln, the yield of feedstock in the product in the kiln was 69 %Met. The size distribution of the feedstock and product particles is given below: Table 6 Feedstock Burned products 850 9.0? 6.67 600 19.65 16j1 425 32.20 30.86 30fl 46.85 50.62 212 67.11 82.82 150 91.25 98.89 106 96.09 99.19 ? 5 97.51 99.21 ~75 100.00 100.00 Continuous flocculation is achieved by Paterson Kelley Pitty. le7 Industrial blender manufactured by Pfy, Ltd. (Pennsylvania, USA) I tried using The milled leucoxin feedstock has the size distribution shown below. Was: Table 7 212 99.5 150 91.2 106 61.0 38 25.9 Into the blender, add 0.6 tons of ground leucoxin per hour to the blender. Add 6 kg per hour of organic binder (PVA) and 1.5 kg per hour of organic binder (PVA). was supplied. installed on the shaft of a set of high speed rotating blades in a coagulation chamber. Water equivalent to 10% of the feed weight was added by means of an attached spray.

The residence time of the mineral in this flocculator was about 20 minutes.

The agglomerated product was dried in a flat dryer to a maximum temperature of 80°C.

The particle size distribution of the dried product is shown below: Table 8 1000 100.0 840 97.6 590 93.4 420 84.4 The dried agglomerated product was transferred to a fluidized bed calcination unit at 1250° C. at 7°C per hour. 3 kg was supplied. The fluidized bed firing unit has a diameter of 0.46 μm and a height higher than the distribution plate. Top) It was 0.56m. Fluidizing gas is the air-rich combustion product of propane. It was. The distillate is sprayed onto the base of a fluidized bed and combustion occurs with the oxygen remaining in the fluidized gas. Therefore, it was further heated. The residence time of the aggregates in the fluidized bed was approximately 60 minutes. Ta.

Fines present in the feed and generated in the combustion fluidized bed are removed from the exhaust combustion gas. It was removed through a thermocyclone. Only 17% of the feedstock The process resulted in “blowover” steam.

The particle size distribution of the combusted agglomerates and blowover of the fluidized bed is as follows: Shown below: Table 9 Product Blowover 850 3, 78 - 600 6, 50 - 425 12.24 - 250 26.42 - 150 51, 52 - 106 86.05 7.25 53 96.89 64.47 Kumachi heat Ne international search report 1, -=Li-p, -0ffice IPt,! 2)-Yo-1 to flash Tl) Fugo Ml Su aTT Sanada Masa α Pseudo 2 Kyo 11 Ko π 3 Steward G’l AL　) JFL1 0sT ON, PCr/A0 15G 202E1787 person υ 49 [1=S/'79 JP 55C31L94E? 00FλN group: (

Claims (19)

[Claims] 1. Increasing the particle size of finely powdered titanium iron(II) mineral containing 45% by weight or more of titanium The method comprises mixing the finely divided mineral with a binder and water to form an aggregate. drying the agglomerate; and sintering the agglomerate. how to. 2. the binder forms a glass when the agglomerate is sintered; or 2. A method according to claim 1, which is capable of exhibiting ceramic sintering properties. 3. The binder is any compound selected from the group consisting of 1) to 15) below. The method according to claim 1, which is selected from: 1) Colloidal silica 2) Silica, water-soluble silicates, or silica/fluorspar mixtures 3) Clay minerals (including bentonite, kaolinite, and montmorillonite) 4) Boehmite 5) Boehmite/silica mixture 6) Geothite 7) Lignosulfonic acid 8) Sodium carbonate (saturated aqueous solution) 9) Sodium silicate 10) Group II element carbonate/clay mineral mixtures 11) Sugars such as molasses 12) Aluminum salt/organic amide mixture 13) Organic solution containing titanium and and inorganic solution 14) Polyvinyl acetate 15) Organic binder emulsified with water. 4. 3. A method according to claim 1 or 2, wherein the binder is bentonite. 5. The aggregates shear the finely divided minerals, binder, and water. According to any one of claims 1 and 2, which is a fine aggregate formed by mixing. the method of. 6. The binder has a dry weight of 0.5 to 5 weight of the total weight of the fine powder and the binder. 6. A method according to any one of claims 1 to 5, comprising a quantity %. 7. The binder constitutes 5 to 15% by weight of the total weight of the fine powder, binder, and water. The method according to any one of claims 1 to 6, comprising: 8. Claims wherein the agglomerate is dried at a temperature range of 75-150°C for less than 30 minutes. 8. The method according to any one of 1 to 7. 9. Claims 1 to 8, wherein the aggregate is sintered at a temperature range of 1000 to 1500°C. The method described in any of the above. 10. The aggregate is sintered at a temperature range of 1200 to 1400°C for 5 minutes to 6 hours. A method according to any one of claims 1 to 9. 11. The claim that the titanium iron (II) mineral is a fine powder mineral and a coarse grain mineral. The method according to any one of ranges 1 to 10. 12. 12. The method of claim 11, wherein the mineral is ground to form a fine powder of the mineral. 13. A claim in which the mineral is crushed to form particles having an average diameter in the range of 1 to 50 μm. The method according to scope 12. 14. A claim in which the sintered aggregate has an average particle size in the range of 100 to 500 μm. The method according to any one of ranges 1 to 13. 15. Claims 1 to 3, wherein the aggregate has an average particle size in the range of 150 to 250 μm. 15. The method according to any one of 14. 16. The method according to any one of claims 1 to 15, wherein the mineral is a detrital mineral. Law. 17. Claims 1 to 16, wherein the mineral contains 85% by weight or more of titanium dioxide. The method described in any of the above. 18. Claims wherein the mineral is rutile, anatase, or leucoxin. 17. The method according to any one of 1 to 16. 19. Agglomerates formed by the method according to any of claims 1 to 18. thing.