Titanium Sponge production process
First, Na reduction method
Titanium tetrachloride is used primarily for the production of titanium sponge, titanium dioxide and titanium trichloride. The preparation of various ways, mainly boiling chlorinated, molten salt chlorination and shaft furnace chlorination 3 kinds of methods. Boiling chlorination is currently the main method for the production of titanium tetrachloride (used in China, Japan and the United States), followed by molten salt chlorination (adopted by the Commonwealth of Independent States), while shaft furnace chlorination has been eliminated. Boiling chlorination is generally low-calcium and magnesium content of high-grade titanium-rich material as raw material, and molten salt chlorination can be accompanied by high calcium and magnesium materials.
1, boiling chlorination
Boiling chlorination is the use of fine particles of titanium-rich material and solid carbonaceous (petroleum coke) reductant, under the action of high temperature, chlorine flow fluoridized state chlorination reaction, thereby preparing titanium tetrachloride method. The law just has to accelerate the gas - solid mass transfer and heat transfer process to enhance the characteristics of production. At home and abroad boiling chlorinated materials used are superior titanium slag, natural rutile, artificial rutile and so on. I
2, molten salt chlorination
Molten salt chlorination is the fine titanium slag or rutile and petroleum coke suspended in the molten salt (mainly composed of KCl. NaCl, MgCl2 and CaCl2 composition) medium, and the introduction of chlorine, thereby preparing titanium tetrachloride method. Electrolytic magnesium can generally be used in waste electrolytes, filling chlorine at 973K ~ 1073K conditions, so the rate of chlorination by the nature of the melt, composition, the type of reductant, the nature of raw materials, chlorination temperature, chlorine concentration and Access speed, melt height, with carbon and other factors. The best molten salt composition in the production of titanium tetrachloride in the CIS is given in table 4.
Molten salt chlorination is a method successfully developed by the former Soviet Union in the 1960s for the production of titanium tetrachloride. The method is not only applicable to the raw material characteristics of the former Soviet Union (about 6% of titanium slag contains CaO + MgO) up to 20 t / m2 ~ 25 t / m2 titanium tetrachloride, molten salt cross-sectional area of ??6m2. Large-scale molten salt chlorination furnace Nissan titanium tetrachloride 120 t ~ 150 t, was originally a rectangular furnace, now changed to a circular furnace, round molten salt chloride furnace size Φ 5.0 m × 8.5 m, within the diameter Φ Is 2.76 m and the rectangle is 4.5 m × 3.5 m × 8.5 m. Round furnace without dead ends, furnace strength increased, 3 years of overhaul 1 times, than the rectangular furnace to extend the life of nearly 1 times. Molten salt chlorination can use a variety of titanium-rich materials. In addition to titanium slag containing calcium and magnesium, is widely used by Red ilmenite (Fe2O3 3TiO2) titanium slag (TiO2 87% ~ 91%), rutile .
Ukraine molten salt chlorination production has 40 years of history, not only for the country's titanium ore concentrate MgO, CaO content is high, but also has the following advantages:
1) high chlorination unit productivity, up to 20 t / m2 · d ~ 25t / m2 · d TiCl4;
2) chlorination temperature is low, 800 ℃, a lot of impurities will not enter into TiCl4 due to chlorination;
3) from charge to industrial titanium tetrachloride, the recovery rate of titanium is high, up to 95%. The molten salt itself has the role of purifying TiCl4, low content of TiCl4 impurity, total content of vanadium, chlorine, silicon, carbon and other impurities ≤2 %; TiCl4 produced more than 98% of the product can make AlCl3, FeCl3, CaO, MgO and SiO2 and other impurities remain in the molten salt medium, and then discharged;
4) the composition of the raw material requirements of the particle size is not high, you can use the small size of titanium slag;
5) The reaction process does not result in COCl2, exhaust gas explosion-free. Exhaust Cl2 and HCl content are very small. The environmental pollution is not large.
3, shaft furnace chlorination
Shaft furnace chlorination is titanium chloride residue (or rutile) and petroleum coke fine grinding, plus binder mixing system and coking, the mass of the material will be stacked in the vertical chlorination furnace, The solid layer state and the role of chlorine in the preparation of titanium tetrachloride method, also known as fixed layer chlorination or chlorination of the group, the law has basically been eliminated.
Second, Mg reduction method
The essence of magnesium reduction is that titanium tetrachloride and metallic magnesium are reacted in an argon atmosphere at 880 C to 950 C to obtain sponge-like metallic titanium and magnesium chloride. Magnesium chloride in the sponge titanium is removed by vacuum distillation and the excess magnesium to obtain pure titanium, distillation condensate can be recovered by melting magnesium metal, magnesium chloride by electrolysis of molten salt electrolysis recovery. Preparation of titanium tetrachloride refined titanium metal, split into two steps of reduction and distillation. In a longer period of time, reduction, distillation are performed step by step, and now has become more integrated, larger.
1, magnesium reduction
The main reaction of magnesium reduction is:
TiCl4 + 2Mg = Ti + 2MgCl2
In the reduction process, trace impurities in TiCl4, such as AlCl3, FeCl3, SiCl4, VOCl3, etc., are reduced by magnesium to generate the corresponding metal, all of which are mixed in the sponge titanium. The impurities mixed in magnesium potassium, calcium, sodium, etc., is also a reducing agent, which respectively TiCl4 reduction and the formation of the corresponding impurity chloride. The process of magnesium reduction includes: Gasification of TiCl4 liquid external diffusion of gaseous TiCl4 and liquid Mg adsorption of TiCl4 and Mg molecules in the active center chemical reaction at the active site crystallization of nuclei growth of titanium grains desorption of MgCl2 MgCl2 outside diffusion. The key step in this process is nucleation of the nuclei, accompanied by heterogeneous nucleation as the chemical reaction progresses.
2, vacuum distillation
The magnesium reduction product after the operation of discharging MgCl2 contains 55-60% of titanium, 25-30% of magnesium, 10-15% of MgCl2 and a small amount of TiCl3 and TiCl2, and the magnesium and MgCl2 in the sponge titanium are separated by a common distillation method.
Titanium Sponge reduction products in the vacuum distillation process to withstand long-term high-temperature sintering, and gradually identified, capillary pores gradually reduced, the dendritic structure disappeared, and finally showed a lump-shaped piece, commonly known as Titanium lump.
3, magnesium reduction, distillation process and equipment
Large-scale titanium metallurgy enterprises are magnesium and titanium joint ventures. Most manufacturers use reduction - distillation integrated process. This process is known as the combined law or semi-united law. It achieved the closed loop of the raw material Mg-Cl2-MgCl2.
Restore - distillation integration equipment, divided into inverted "U" type and "I" type two. Inverted "U" type equipment is to restore the tank (distillation tank) and the condensate tank with a valve between the pipe connection, set up a special heating device, the entire system equipment before the reduction of the Assembly. "I" -type integrated process system equipment such as the one-time reduction before the assembly, known as the joint law equipment; and the first assembly of the reduction equipment to be restored is completed, hot and then condensate tank assembled for distillation operation system Equipment is called a series combination of equipment, the middle with magnesium plug "transition section" link.
First, Na reduction method
Titanium tetrachloride is used primarily for the production of titanium sponge, titanium dioxide and titanium trichloride. The preparation of various ways, mainly boiling chlorinated, molten salt chlorination and shaft furnace chlorination 3 kinds of methods. Boiling chlorination is currently the main method for the production of titanium tetrachloride (used in China, Japan and the United States), followed by molten salt chlorination (adopted by the Commonwealth of Independent States), while shaft furnace chlorination has been eliminated. Boiling chlorination is generally low-calcium and magnesium content of high-grade titanium-rich material as raw material, and molten salt chlorination can be accompanied by high calcium and magnesium materials.
1, boiling chlorination
Boiling chlorination is the use of fine particles of titanium-rich material and solid carbonaceous (petroleum coke) reductant, under the action of high temperature, chlorine flow fluoridized state chlorination reaction, thereby preparing titanium tetrachloride method. The law just has to accelerate the gas - solid mass transfer and heat transfer process to enhance the characteristics of production. At home and abroad boiling chlorinated materials used are superior titanium slag, natural rutile, artificial rutile and so on. I
2, molten salt chlorination
Molten salt chlorination is the fine titanium slag or rutile and petroleum coke suspended in the molten salt (mainly composed of KCl. NaCl, MgCl2 and CaCl2 composition) medium, and the introduction of chlorine, thereby preparing titanium tetrachloride method. Electrolytic magnesium can generally be used in waste electrolytes, filling chlorine at 973K ~ 1073K conditions, so the rate of chlorination by the nature of the melt, composition, the type of reductant, the nature of raw materials, chlorination temperature, chlorine concentration and Access speed, melt height, with carbon and other factors. The best molten salt composition in the production of titanium tetrachloride in the CIS is given in table 4.
Molten salt chlorination is a method successfully developed by the former Soviet Union in the 1960s for the production of titanium tetrachloride. The method is not only applicable to the raw material characteristics of the former Soviet Union (about 6% of titanium slag contains CaO + MgO) up to 20 t / m2 ~ 25 t / m2 titanium tetrachloride, molten salt cross-sectional area of ??6m2. Large-scale molten salt chlorination furnace Nissan titanium tetrachloride 120 t ~ 150 t, was originally a rectangular furnace, now changed to a circular furnace, round molten salt chloride furnace size Φ 5.0 m × 8.5 m, within the diameter Φ Is 2.76 m and the rectangle is 4.5 m × 3.5 m × 8.5 m. Round furnace without dead ends, furnace strength increased, 3 years of overhaul 1 times, than the rectangular furnace to extend the life of nearly 1 times. Molten salt chlorination can use a variety of titanium-rich materials. In addition to titanium slag containing calcium and magnesium, is widely used by Red ilmenite (Fe2O3 3TiO2) titanium slag (TiO2 87% ~ 91%), rutile .
Ukraine molten salt chlorination production has 40 years of history, not only for the country's titanium ore concentrate MgO, CaO content is high, but also has the following advantages:
1) high chlorination unit productivity, up to 20 t / m2 · d ~ 25t / m2 · d TiCl4;
2) chlorination temperature is low, 800 ℃, a lot of impurities will not enter into TiCl4 due to chlorination;
3) from charge to industrial titanium tetrachloride, the recovery rate of titanium is high, up to 95%. The molten salt itself has the role of purifying TiCl4, low content of TiCl4 impurity, total content of vanadium, chlorine, silicon, carbon and other impurities ≤2 %; TiCl4 produced more than 98% of the product can make AlCl3, FeCl3, CaO, MgO and SiO2 and other impurities remain in the molten salt medium, and then discharged;
4) the composition of the raw material requirements of the particle size is not high, you can use the small size of titanium slag;
5) The reaction process does not result in COCl2, exhaust gas explosion-free. Exhaust Cl2 and HCl content are very small. The environmental pollution is not large.
3, shaft furnace chlorination
Shaft furnace chlorination is titanium chloride residue (or rutile) and petroleum coke fine grinding, plus binder mixing system and coking, the mass of the material will be stacked in the vertical chlorination furnace, The solid layer state and the role of chlorine in the preparation of titanium tetrachloride method, also known as fixed layer chlorination or chlorination of the group, the law has basically been eliminated.
Second, Mg reduction method
The essence of magnesium reduction is that titanium tetrachloride and metallic magnesium are reacted in an argon atmosphere at 880 C to 950 C to obtain sponge-like metallic titanium and magnesium chloride. Magnesium chloride in the sponge titanium is removed by vacuum distillation and the excess magnesium to obtain pure titanium, distillation condensate can be recovered by melting magnesium metal, magnesium chloride by electrolysis of molten salt electrolysis recovery. Preparation of titanium tetrachloride refined titanium metal, split into two steps of reduction and distillation. In a longer period of time, reduction, distillation are performed step by step, and now has become more integrated, larger.
1, magnesium reduction
The main reaction of magnesium reduction is:
TiCl4 + 2Mg = Ti + 2MgCl2
In the reduction process, trace impurities in TiCl4, such as AlCl3, FeCl3, SiCl4, VOCl3, etc., are reduced by magnesium to generate the corresponding metal, all of which are mixed in the sponge titanium. The impurities mixed in magnesium potassium, calcium, sodium, etc., is also a reducing agent, which respectively TiCl4 reduction and the formation of the corresponding impurity chloride. The process of magnesium reduction includes: Gasification of TiCl4 liquid external diffusion of gaseous TiCl4 and liquid Mg adsorption of TiCl4 and Mg molecules in the active center chemical reaction at the active site crystallization of nuclei growth of titanium grains desorption of MgCl2 MgCl2 outside diffusion. The key step in this process is nucleation of the nuclei, accompanied by heterogeneous nucleation as the chemical reaction progresses.
2, vacuum distillation
The magnesium reduction product after the operation of discharging MgCl2 contains 55-60% of titanium, 25-30% of magnesium, 10-15% of MgCl2 and a small amount of TiCl3 and TiCl2, and the magnesium and MgCl2 in the sponge titanium are separated by a common distillation method.
Titanium Sponge reduction products in the vacuum distillation process to withstand long-term high-temperature sintering, and gradually identified, capillary pores gradually reduced, the dendritic structure disappeared, and finally showed a lump-shaped piece, commonly known as Titanium lump.
3, magnesium reduction, distillation process and equipment
Large-scale titanium metallurgy enterprises are magnesium and titanium joint ventures. Most manufacturers use reduction - distillation integrated process. This process is known as the combined law or semi-united law. It achieved the closed loop of the raw material Mg-Cl2-MgCl2.
Restore - distillation integration equipment, divided into inverted "U" type and "I" type two. Inverted "U" type equipment is to restore the tank (distillation tank) and the condensate tank with a valve between the pipe connection, set up a special heating device, the entire system equipment before the reduction of the Assembly. "I" -type integrated process system equipment such as the one-time reduction before the assembly, known as the joint law equipment; and the first assembly of the reduction equipment to be restored is completed, hot and then condensate tank assembled for distillation operation system Equipment is called a series combination of equipment, the middle with magnesium plug "transition section" link.
