Method for preparing titanium and titanium obtained by the method

Cross reference to related applications

This application claims priority from Chinese application no.<de-docref CY="CN" DNUM="201110293657" KI="">201110293657.8</de-docref>, filed September 30, 2011, entitled "Method for Production of Metallic Titanium and Metallic Titanium Obtained with the Method," which is expressly and fully incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a method for producing metallic titanium

Background of the invention

Titanium and titanium alloys have certain advantages, such as low density, high specific strength, high heat and cold resistance, high corrosion resistance, outstanding biocompatibility, etc., and are therefore praised as "future metal", "spatial metal" and "marine metal".

Titanium belongs to a genus of rare metals; however, the element titanium ranks seventh in the earth's crust (0.45% by weight) and is far more abundant than many of the common metals. Due to the active nature of titanium, the requirements of the refining process are very strict and thus it is difficult to produce titanium in large quantities. That is why titanium is classified as a “rare” metal material. At present, the Kroll process is the world's most popular industrial production method of metallic titanium, which involves several operations, mainly including: production of titanium chloride from titanium oxide, reduction of magnesium by vacuum distillation, post-treatment of the product, magnesium electrolysis, etc. The advantage of the Kroll -process lies in the reuse of chlorine and magnesium. However, the process also has disadvantages, such as a long process duration, low reduction efficiency and high consumption of reducing agents. Therefore, the production cost of metallic titanium is very high. As titanium metal finds wider use in a variety of industrial applications - from aerospace to military to civilian use - the research and development of new titanium refining techniques to reduce the production costs of titanium metal has become a key topic of research in of the titanium metallurgy industry.

So far, molten salt electrolysis for titanium production has been considered the most promising alternative to the Kroll process. The molten salt electrolysis process typically involves a TiO₂Molten salt electrolysis, a TiCl₄Molten salt electrolysis and a molten salt electrolysis of a carbothermal reduced product of TiO₂.

The FFC Cambridge process is a typical TiO₂Molten salt electrolysis, in which solid TiO₂as cathode, graphite as anode and CaCl₂used as an electrolyte. When the applied external voltage is lower than the decomposition voltage of the molten salt, the oxygen at the cathode enters the electrolyte in ionic form, spreads to the anode and combines with carbon to form CO₂or CO gas emanating from the anode while metallic titanium remains at the cathode. Compared with the conventional molten salt electrolysis method, the FFC method is an innovative process that separates metallic titanium and oxygen to obtain titanium and has several advantages such as environmental friendliness, process simplicity and continuous production. However, the FFC process has so far only been used successfully under laboratory conditions, but not in industrial production, mainly because the FFC process has the following problems: the TiO₂-Cathode has high resistivity, which makes stable electrolysis difficult; any impurities in the cathode (TiO₂) remain in the titanium and the product obtained must therefore be further purified. Consequently, the production cost of metallic titanium is too high.

The Ginatta electrolysis process is a typical TiCl₄Molten Salt Electrolysis, and has been the subject of long-term and in-depth research in the United States; Japan, the former USSR, Italy, France, China etc. and several small plants have been established. However, these plants were ultimately closed because the expected technical and economic figures were not achieved due to problems in the actual production, such as damage to the diaphragm and the formation of dendritic crystals.

<de-docref CY="US" DNUM="7410562" KI="B2">US 7 410 562 B2</de-docref>describes an electrolytic process for the production of metallic titanium using a titanium-containing anode, a metallic cathode and a molten salt as the electrolyte. The method described in this document essentially corresponds to the known MER method.

<de-docref CY="US" DNUM="6051117" KI="A">US 6 051 117 A</de-docref>describes a titanium-containing anode having a porous structure for use in an electrolytic process. This method is primarily used to create a three-dimensional structure of a base precursor with open pores, with the precursor then being re-expanded and metallized.

SUMMARY OF THE INVENTION

In order to overcome the disadvantages of the existing methods for producing metallic titanium, the present invention proposes a novel method for producing metallic titanium and metallic titanium obtained by this method.<ol id="ol_0001" ol-style="1"><li id="ol_0001_0001">1. The present invention proposes a method for the production of metallic titanium, comprising: Using a titanium-bearing material as an anode, a metallic material as a cathode, and a molten salt as an electrolyte, and subjecting it to electrolysis under electrolytic conditions to obtain metallic titanium, the titanium-bearing material having a porous structure with an average pore diameter of 1 - 10 mm and a porosity of 20 - 60% and at least part of the titanium element in the titanium bearing material in the form of TiO_xis present, where 2&gt;x&gt;0, wherein the titanium-bearing material is produced by a method comprising the following steps:<ol id="ol_0002" ol-style="1"><li id="ol_0002_0001">(1) Bringing a molten titania-containing raw material into contact with a carbonaceous reducing agent so that all or part of the titania in the titania-containing raw material becomes TiO_xis reduced to obtain molten titanium slag which is the reduction product of TiO_xcontains;</li><li id="ol_0002_0002">(2) Cooling the molten titanium slag to be formed containing the reduction product of TiO_xcontains,</li></ol></li></ol>wherein the contacting in step (1) is carried out at a temperature of 1650 - 2000°C and a pressure of -100 - 100 Pa and for a duration of 2 - 10 h.

The inventor of the present invention has found that in the case of a controlled average pore diameter of the titanium-bearing material of 1 - 10 mm and a controlled porosity of 20 - 60%, the titanium-bearing material can meet the requirements for an anode and that during electrolysis generated gases (e.g. CO, CO₂etc.) can propagate successfully and therefore the purity and yield rate of metallic titanium are very high. In addition, the existing molten salt electrolysis process for the carbothermal reduction product of titanium oxide is typically the MER process; ball milling and mixing the titanium oxide and carbonaceous reductant, compression molding and sintering to form the anode; or the titanium oxide and carbonaceous reductant are mixed and sintered, and then mixed with carbonaceous reductant and binder, compression molded and sintered to form the anode. The inventor of the present invention found that the process is very complex and the anode obtained is easily breakable and does not meet the requirements for the application if it is not pressed firmly enough in manufacture, whereas serious problems such as anodic polarization in the electrolytic process can occur if the anode has been pressed too tightly. Furthermore, anode material obtained by compression molding and sintering usually has small pore diameter and low porosity. Consequently, it is difficult for the gases (e.g. CO) generated in the electrolytic process to diffuse, and therefore the electrolytic effect is not satisfactory. On the other hand, with the method for producing titanium-containing material in a preferred embodiment of the present invention, a molten raw material containing titanium oxide is first brought into contact with a carbonaceous reducing agent so that the titanium oxide in the molten raw material containing titanium oxide is wholly or partially converted into TiO_xis reduced to obtain molten titanium slag which is the reduction product of TiO_xcontains. Then the titanium slag, which is the reduction product of TiO_xcontains, refrigerated to be shaped; as a result, the reduction product obtained can be directly cooled to form the anode without additional treatment (e.g. mixing, ball milling and pressing the titanium oxide-containing raw material and the carbonaceous reducing agent to form the anode, and then sintering; or pressing the mixture of the obtained solid reduction products and binder to form the anode and subsequent sintering); therefore the procedure is simplified; on the other hand, the reduction product obtained by bringing titanium oxide-containing raw material into contact with the carbonaceous reducing agent may contain one or more members of the group TiO, Ti₂O₃, Ti₃O₅ und Ti₄O₇contain. The obtained reduction product is kept in a molten state by controlling contact conditions, and the molten reduction product is directly cooled for molding. Thus, the reduction product is in a homogeneous state, the anode thereby obtained has a homogeneous composition, and the electrolytic process is stable.

Further characteristics and advantages of the present invention are detailed in the following description of the embodiments.

Detailed description of the embodiments

The embodiments of the present invention are described below. It should be noted that the embodiments set forth herein are for description and explanation of the present invention only and should not be construed as limiting the present invention.

The method for producing metallic titanium proposed by the present invention includes: using a titanium-bearing material as an anode, a metallic material as a cathode and a molten salt as an electrolyte and conducting electrolysis under electrolytic conditions to obtain metallic titanium, the titanium-bearing material having a porous structure and an average pore diameter of 1 - 10 mm, preferably 3 - 7 mm, and a porosity of 20 - 60%, preferably 40 - 60%, and wherein at least a portion of the titanium element in the titanium-bearing material is in the form of TiO_xwhere 2&gt;x&gt;0.

It is known to those skilled in the art that the fusion and electrolysis process requires that the anode must have a certain solubility in the molten salt electrolyte. However, since titanium oxide has a very low or no solubility in molten salt electrolyte, it cannot be used directly as an anode for the production of metallic titanium by electrolysis, therefore x ≠ 2. However, the solubility of titanium oxides of lower valence of TiO_x(2&gt;x&gt;0) meet the requirements for molten salt electrolysis. In addition, it is known from the principle of molten salt electrolysis that titanium oxides of low valence of TiO_x(2&gt;x&gt;0) can also meet other requirements for the anode for molten salt electrolysis. Therefore, the value of x is not specifically limited in the present invention as long as it is within the above range.

Although the proportion of TiO_x(2&gt;x&gt;0) in the titanium-containing material can be set and varied over a wide range, is the proportion of TiO_xin the titanium bearing material in the present invention is preferably set at ≥ 45 wt% in order to increase the efficiency of electrolysis.

No specific limitation is defined for the production method of the titanium-bearing material in the present invention as long as the method can control the average pore diameter and the porosity in the above range. The titanium-bearing material is manufactured using a production process that includes the following steps:<ol id="ol_0003" ol-style="1"><li id="ol_0003_0001">(1) Bringing a molten titania-containing raw material into contact with a carbonaceous reducing agent so that all or part of the titania in the titania-containing raw material becomes TiO_xis reduced to obtain molten titanium slag which is the reduction product of TiO_xcontains;</li><li id="ol_0003_0002">(2) Cooling the molten titanium slag to be formed, which is the reduction product of TiO_xcontains.</li></ol>

Here it is established that the cooling is a natural cooling without the application of external pressure. The cooling conditions usually include pressure and cooling rate. In order to obtain a titanium-containing material having the above-mentioned pore diameter and porosity, the cooling is carried out at a pressure of 0.9×10, for example⁵ - 1,2×10⁵Pa (absolute pressure) and a cooling rate of 100 - 150 °C/h.

In the present invention, as set forth above, the molten titanium oxide-containing raw material is brought into contact with a carbonaceous reducing agent, and the contacting conditions are controlled so that the reduction of the titanium compounds in the titanium oxide-containing raw material to low-valence (higher than zero-valent and lower as tetravalent) is guaranteed and the products are in the molten state, so that the reduction products of different valence can interact with each other to achieve a homogeneous state. More importantly, after the titanium slag containing the molten reduction product of low valence titanium is cooled. Moreover, in order to be shaped, the titanium-bearing material is in a porous structure, which effectively ensures that the gases (CO, CO₂etc.) that arise during the electrolysis, spread successfully and the result of the electrolysis is therefore very good.

In the present invention, the purpose of contacting the titania-containing raw material with the carbonaceous reducing agent is to reduce the high-valence titanium in the titania-containing raw material to low-valence titanium which has voids and has a species between conductor and semiconductor. Therefore, the low valency titanium has higher electrical conductivity and can be dissolved in the molten salt electrolyte. The contact conditions include contact temperature, contact pressure and contact time, and the contact conditions can be considered appropriate as long as they ensure that the titanium oxide in the titanium oxide-containing raw material can be reduced to low-valence titanium and molten titanium slag can be recovered which is the reduction product of the Includes low tier Titans. The contacting takes place at a temperature of 1650 - 2000 °C, a pressure of -100 - 100 Pa (absolute pressure) and within 2 - 10 h. In particular, the contacting takes place at a temperature of 1650-1750°C, a pressure of -50-50 Pa (absolute pressure) and within 3-5 hours. Under these conditions, the titanium oxide in the titanium oxide-containing raw material is completely or almost completely reduced to low-valence titanium.

Due to the reducing ability of the carbonaceous reductant, titanium oxide can be reduced to the sub-four valence product, such as one or more selected from the group consisting of TiO, Ti, rather than to a mere substance₂O₃, Ti₃O₅ und Ti₄O₇, when the redox reaction takes place between the carbonaceous reducing agent and the raw material containing titanium oxide. It is known to those skilled in the art that the fusion electrolysis process requires that the anode has a certain solubility in the molten salt electrolyte. However, since titanium oxide has a very low or has no solubility in molten salt electrolyte, it cannot be used directly as an anode to obtain metallic titanium by electrolysis; hence x ≠ 2. However, the solubility of titanium oxides of TiO_x(2&gt;x&gt;0) in the molten salt electrolyte meet the requirements of electrolysis. In addition, it is known from the principle of molten salt electrolyte that titanium oxides with low valency of TiO_x(2&gt;x&gt;0) can also meet other requirements of the anode to the molten salt electrolyte. Therefore, in the process proposed by the present invention, the composition of the reduction product is not specifically limited as long as the titanium oxide is reduced to low-valence titanium compounds, for example, one or more of the group consisting of TiO, Ti₂O₃, Ti₃O₅ und Ti₄O₇.

In the present invention, the amount ratio of raw material containing titanium compounds titanium oxide to carbon in the carbonaceous reducing agent can vary over a wide range, e.g., calculated for titanium oxide; the molar ratio of titanium compounds in the titanium oxide-containing raw material to carbon in the carbonaceous reducing agent may be 1:1-3. In addition, due to the fact that the titanium oxide-containing raw material usually contains other reducing substances, such as iron ions, etc., the actual amount of carbonaceous reducing agent is often slightly higher than the amount needed to improve the reduction result. Preferably, the molar ratio, calculated for titanium oxide, of titanium compounds in the titanium oxide-containing raw material to carbon in the carbonaceous reducing agent is 1:1.5-3, in particular 1:1.5-2.5.

In the present invention, the raw material containing titanium oxide may be any raw material containing titanium oxide. The titanium oxide-containing material can be, for example, titanium concentrate and/or titanium-bearing slag. The titanium concentrates are refined from ilmenite or titaniferous magnetite and contain mainly titanium oxide (42 - 65 wt%), iron sesquioxide (5 - 40 wt%), iron oxide (5 - 40 wt%) and some phosphorus chemical compounds -, sulphur, magnesium and calcium elements (2 - 10% by weight). The titaniferous slag refers to the slag produced when other valuable metals are extracted from titaniferous minerals and mainly contains titanium oxide (15 - 30 wt%), calcium oxide (10 - 25 wt%), alumina (10th - 20% by weight) and silicon dioxide (10 - 28% by weight).

In the present invention, the carbonaceous reducing agent may be any carbonaceous reducing agent as long as it can reduce the titanium oxide in the titanium oxide-containing raw material to low-valent titanium compounds (e.g., trivalent and divalent titanium compounds). The carbonaceous reductant may be, for example, one or more of the group consisting of lean coal, soft coal, charcoal, coke, and refined coke. Lean bit coal is the highest rank coal, high carbon content (80 wt% or more) and low volatile content (less than 10 wt%). The soft carbon has a carbon content of 75 - 90% by weight. Charcoal has a carbon content of 65 - 95% by weight. Coke is made from soft coal by heating at 950 - 1050 °C, drying, thermolyzing, melting, agglomerating, solidifying, contracting, etc. obtained and has a carbon content of 75 - 85% by weight. The refined coke is a product obtained by distilling crude oil to separate light oil and heavy oil, and then treating the heavy oil by pyrolysis. The appearance of the coke is black blocks (or granules) of irregular shape and size and shows a metallic luster; the coke granules have a porous structure and a carbon content of 90% by weight or higher. The remaining components are hydrogen, oxygen, nitrogen, sulfur and metal elements.

The kind of the metal for the cathode is not specifically defined in the present invention as long as the metal material can cooperate with the anode of the present invention to achieve electrolysis and manufacture metallic titanium. However, in order to improve the life of the anode and the purity of the metallic titanium obtained, the metal material for the cathode may preferably be one or more of the group consisting of carbon steel, molybdenum, copper and nickel.

Usually, electrolyte refers to a chemical compound that can conduct electricity when dissolved in water or when in a molten state. In the present invention, for the purpose of improving the purity of the obtained metallic titanium and reducing the intrusion of foreign matter, a molten salt material is preferably used as the electrolyte. The molten salt material may be, for example, a molten salt formed from alkali chloride and/or a chloride of an alkaline earth metal. The alkali chloride can be, for example, sodium chloride and/or potassium chloride. The chloride of an alkaline earth metal can be magnesium chloride and/or calcium chloride.

Although the electrolysis conditions do not have a significant impact on the purity of the metallic titanium obtained, in the present invention, to balance efficiency and yield, the electrolysis conditions preferably include an anode current density of 0.05 - 2 A/cm²and a cathode current density of 0.05 - 2 A/m², in particular an anode current density of 0.1-1 A/cm²and a cathode current density of 0.1-1 A/cm².

In the present invention, the temperature of the molten salt (i.e., the temperature of electrolysis) can vary over a wide range as long as the temperature is higher than the melting point of the salt constituting the molten salt and lower than the boiling point and decomposition temperature of the salt which forms the molten salt. The temperature of the electrolysis can be, for example, 600-900°C, preferably 600-800°C. The timing of the electrolysis can be selected depending on the amount of the low-valent titanium to be electrolyzed and the conditions of the electrolysis so that at least 90% of the low-valent titanium is converted into metallic titanium.

In the present invention, the metallic titanium produced by electrolysis tends to react with the oxygen in the air at the temperature of electrolysis. In order to improve the purity of the metallic titanium obtained, the electrolysis is therefore preferably carried out in an inert gas atmosphere. The protective gas atmosphere can optionally consist of nitrogen and one or more noble gases from the periodic table of the elements and is preferably argon gas.

Furthermore, another method for the production of metallic titanium is described, comprising the following steps:<ol id="ol_0004" ol-style="1"><li id="ol_0004_0001">(1) Bringing a molten titania-containing raw material into contact with a carbonaceous reducing agent so that all or part of the titania in the titania-containing raw material becomes TiO_xis reduced where 2&gt;x&gt;0 to obtain molten titanium slag which is the reduction product of TiO_xcontains;</li><li id="ol_0004_0002">(2) Cooling the molten titanium slag to be formed, which is the reduction product of TiO.sub.2 produced in step (1)._xto obtain a titanium bearing material, wherein the cooling is carried out so that the average pore diameter of the titanium bearing material is 1 - 10 mm and the porosity is 20 - 60%;</li><li id="ol_0004_0003">(3) Using the titaniferous material produced in the step (2) as an anode, a metallic material as a cathode, and a molten salt as an electrolyte, and conducting electrolysis under electrolytic conditions to obtain metallic titanium.</li></ol>

The kind and amount of the substances in the above steps, the contact conditions for the contact between the titanium oxide-containing raw material and the carbonaceous reducing agent, the cooling conditions and the electrolysis conditions have already been described above and will not be detailed here.

In the following, further embodiments of the present invention are described in detail.

In the following and comparative examples, the yield rate of metallic titanium is equal to the actual yield of metallic titanium / the theoretical yield of metallic titanium x 100%, the average pore diameter of the titanium-bearing material is observed with a scanning electron microscope (SEM; by Hitachi, Model S-4700) is measured and the porosity is determined using a nitrogen adsorption analysis.

example 1

100 g of molten titanium concentrates manufactured by Panzhihua (where TiO₂: 47,5 Gew.-%, Fe₂O₃: 5.74% by weight, FeO: 34.48% by weight, CaO: 1.42% by weight, MgO: 6.22% by weight), and 14 g of lean bituminous coal (where carbon content is 78, 5% by weight) in an electric furnace and melted for 5 hours at 1750°C temperature and -50 Pa pressure (absolute pressure) to obtain molten titanium slag. The molten titanium slag is poured into a diameter 400x600 cast steel mold and cooled without applying external pressure (pressure: 0.9×10⁵Pa, cooling rate: 150 °C/h) to obtain a titanium-bearing material with a porous structure, wherein the average pore diameter of the titanium-bearing material is 5.75 mm and the porosity is 45%. The titanium-bearing material is used as the anode, an 80x600 diameter carbon steel rod as the cathode and NaCl-KCl (1:1 weight ratio) as the molten salt electrolyte and electrolyzed for 300 min at 820 °C under an argon protective gas, with the anode current density being 0.2 A/cm²and the cathode current density 0.2 A/cm²amounts to. After completion of the electrolysis, the cathode is taken out, naturally cooled, washed with 0.5 wt% diluted hydrochloric acid and deionized water, and then the product is dried to obtain 22.5 g of a metallic titanium-containing product. The yield rate of the metallic titanium is 46.66%. During the electrolysis process, the current fluctuation is very small, which indicates the stability of the electrolysis. The elements contained in the metallic titanium-containing product determined by X-ray fluorescence analysis are distributed as follows: Ti: 98.5% by weight, Fe: 0.95% by weight, O: 0.37% by weight and H: 0, 18% by weight.

Example 2

60 g of molten titanium concentrates manufactured by Panzhihua (where TiO₂: 47,5 Gew.-%, Fe₂O₃: 5.74% by weight, FeO: 34.48% by weight, CaO: 1.42% by weight, MgO: 6.22% by weight), 40 g of titanium concentrates manufactured by Yunan (where TiO₂: 49,85 Gew.-%, Fe₂O₃: 9.68% by weight, FeO: 36.50% by weight, CaO: 0.24% by weight, MgO: 1.99% by weight), and 20 g of lean bituminous coal (where carbon content is 78, 5% by weight) in an electric furnace and melted for 3 hours at 1650°C temperature and 50 Pa (absolute pressure) to obtain molten titanium slag. The molten titanium slag is poured into a 300×600 diameter cast steel mold and cooled without applying external pressure (pressure: 1.0×10⁵Pa, cooling rate: 100°C/h) to obtain a titanium-bearing material with a porous structure, the average pore diameter of the titanium-bearing material being 6.5 mm and the porosity being 55.3%. The titanium-bearing material is used as the anode, a 60x600 diameter carbon steel rod as the cathode and NaCl-KCl (weight ratio 1:1) as the molten salt electrolyte and electrolyzed for 300 min at 900 °C under inert gas, with the anode current density being 2 A/cm²and the cathode current density 1 A/cm²amounts to. During the electrolysis process, the current fluctuation is very small, which indicates the stability of the electrolysis. After completion of the electrolysis, the cathode is taken out, naturally cooled, washed with 0.5 wt% diluted hydrochloric acid and deionized water, and then the product is dried to obtain 14 g of a metallic titanium-containing product. The yield rate of the metallic titanium is 48.03%. The elements contained in the metallic titanium-containing product determined by X-ray fluorescence analysis are distributed as follows: Ti: 97.78% by weight, Fe: 0.85% by weight, O: 1.25% by weight and H: 0, 12% by weight.

Example 3

100 g of molten titanium concentrates manufactured by Yunan (where TiO₂: 49,85 Gew.-%, Fe₂O₃: 9.68% by weight, FeO: 36.50% by weight, CaO: 0.24% by weight, MgO: 1.99% by weight), and 22 g of coke (where carbon content is 85.5 % by weight) in an electric furnace and melted for 4 hours at 1700°C temperature and 5 Pa (absolute pressure) to obtain molten titanium slag. The molten titanium slag is poured into a diameter 200x400 cast steel mold and cooled without applying external pressure (pressure: 1.2×10⁵Pa, cooling rate: 120°C/h) to obtain a titania material having a porous structure, wherein the average pore diameter of the titania material is 3.5 mm and the porosity is 60%. The titanium-bearing material is used as the anode, a 50x400 diameter carbon steel rod as the cathode and NaCl-KCl (weight ratio 1:1) as the molten salt electrolyte and electrolyzed for 210 min at 850 °C under protective gas, with the anode current density being 1 A/cm²and the cathode current density 1.5 A/cm²amounts to. During the electrolysis process, the current fluctuation is very small, which indicates the stability of the electrolysis. After completion of the electrolysis, the cathode is taken out, naturally cooled, washed with 0.5 wt% diluted hydrochloric acid and deionized water, and then dried to obtain 23.5 g of a metallic titanium-containing product. The yield rate of the metallic titanium is 46.33%. The elements contained in the metallic titanium-containing product determined by X-ray fluorescence analysis are distributed as follows: Ti: 98.28% by weight, Fe: 0.55% by weight, O: 1.05% by weight and H: 0, 12% by weight.

Example 4

Metallic titanium is produced using the process described in Example 2, with the following difference: The contact temperature between the molten titanium concentrates produced by Panzhihua and the lean bit coal is 1600°C. After completion of the electrolysis, the cathode is taken out, naturally cooled, washed with 0.5 wt% diluted hydrochloric acid and deionized water, and the product is subsequently dried to obtain 12 g of a metallic titanium-containing product. The yield rate of the metallic titanium is 41.05%. During the electrolysis process, the current fluctuation is very small, which indicates the stability of the electrolysis. The elements contained in the metallic titanium-containing product determined by X-ray fluorescence analysis are distributed as follows: Ti: 97.5% by weight, Fe: 1.55% by weight, O: 1.25% by weight and H: 0, 12% by weight.

Comparative example 1

Metallic titanium is produced using the method described in Example 1, with the following difference: The anode for the production of metallic titanium is produced using the following method:<ul id="ul_0005" list-style="none"><li id="ul_0005_0001">100 g of molten titanium concentrates manufactured by Panzhihua (where TiO₂: 47,5 Gew.-%, Fe₂O₃: 5.74% by weight, FeO: 34.48% by weight, CaO: 1.42% by weight, MgO: 6.22% by weight), and 14 g lean bituminous coal (carbon fraction 78.5 % by weight) in an electric furnace and melted for 5 hours at 1750°C temperature and -50 Pa (absolute pressure) to obtain molten titanium slag. The molten titanium slag is cooled and then poured into a 400x600 diameter cast steel mold and pressed into the desired shape under 50000psi pressure to obtain shaped titaniferous material, the average pore diameter of the titaniferous material is 200nm and the porosity is 10%. During the process of electrolysis, the current fluctuation is high, indicating the instability of the electrolysis. After completion of the electrolysis, the cathode is taken out, naturally cooled, washed with 0.5 wt% diluted hydrochloric acid and deionized water, and then the product is dried to obtain 11.9 g of a metallic titanium-containing product. The yield rate of the metallic titanium is 24.30%. The elements contained in the metallic titanium-containing product determined by X-ray fluorescence analysis are distributed as follows: Ti: 97% by weight, Fe: 1.95% by weight, O: 0.57% by weight and H: 0.48% by weight %.</li></ul>

Comparative example 2

Metallic titanium is produced using the method described in Example 1, with the following difference: The anode for the production of metallic titanium is produced using the following method:<ul id="ul_0006" list-style="none"><li id="ul_0006_0001">100 g of molten titanium concentrates manufactured by Panzhihua (where TiO₂: 47,5 Gew.-%, Fe₂O₃: 5.74% by weight, FeO: 34.48% by weight, CaO: 1.42% by weight, MgO: 6.22% by weight), and 14 g of lean bituminous coal (where carbon content is 78, 5% by weight) in a ball mill and ground for 60 min. Then the mixture is placed in a 200x400 diameter cast steel mold, pressed under 50000 psi pressure into the desired shape and then sintered for 5 h at 1750 °C temperature and under - 50 Pa (absolute pressure) to obtain titanium-bearing material with the average pore diameter of the titanium-bearing material is 300 nm and the porosity is 15%. During the process of electrolysis, the current fluctuation is high, indicating the instability of the electrolysis. After completion of the electrolysis, the cathode is taken out, naturally cooled, washed with 0.5 wt% diluted hydrochloric acid and deionized water, and then the product is dried to obtain 12.1 g of a metallic titanium-containing product. The yield rate of the metallic titanium is 24.73%. The elements contained in the metallic titanium-containing product determined by X-ray fluorescence analysis are distributed as follows: Ti: 97.08% by weight, Fe: 1.45% by weight, O: 0.57% by weight and H: 0. 48% by weight.</li></ul>

From the comparison between Example 1 and Comparative Examples 1 and 2, it can be seen that both the yield rate and the purity of the product are higher when the method for producing metallic titanium proposed in the present invention is used. In addition, the reduction product obtained in the present invention is in a molten state, which allows the reduction products in different valency states to interact with each other to achieve a desired result. In addition, the produced titanium-bearing material has a porous structure after being cooled for molding, which effectively ensures that the gases (CO, CO₂etc.) spread successfully and the electrolysis process is more stable.

While some of the preferred embodiments of the present invention are described above, the present invention is not limited to the details of these embodiments. Those skilled in the art can make changes and variations in the technical construct of the present invention without departing from the gist of the present invention. However, all modifications and variations should be considered as falling within the protected scope of the present invention.

Furthermore, it should be noted that the specific technical features described in the above embodiments can be combined in any reasonable manner unless a contradiction arises. In order to avoid unnecessary repetition, not all possible combinations of the present invention are specifically described.

Moreover, the various embodiments of the present invention can be combined as freely as necessary as long as the combinations do not deviate from the gist of the present invention. However, all such changes are to be construed as included within the scope disclosed by the present invention.