Titanium is one of the most abundant elements in the earth’s crust. However, since titanium was discovered more than 200 years ago, it has been listed as a rare metal due to the difficulty of refining. Since the second half of the 20th century, with the development of the aerospace industry, titanium training has been valued by everyone. Titanium is a high-melting point metal, and its density is relatively low. The strength of titanium alloy is comparable to high-strength steel. Together, it has excellent corrosion resistance. These advantages of titanium alloy make it truly known as “space metal”. It also has the reputation of “ocean metal”. However, it has stopped so far, and the global output value of titanium metal is less than 1% of the output value of primary aluminum, nor less than 1/10 of the output value of titanium dioxide. The primary reason for this appearance is the shortcomings of the current titanium production method. At present, titanium metal at home and abroad is mainly produced by magnesium heat recovery TiCl4, which is called Kroll method. The basic process is: the stainless steel reactor equipped with metal magnesium is heated to 950°C, written into the refined TiCl4, and the reaction occurs and releases heat. After the reaction is completed, the by-products MgCl2 and the remaining magnesium are vacuumed away and recycled After the reverberator cools down, open the reverberator to obtain sponge titanium. The Kroll method has been criticized from the beginning for its high cost and low recovery power. The main reasons for the high production cost of this method are: (1) time-consuming, the whole process takes 17 days from the beginning of TiO2 chlorination to the production of titanium sponge; (2) energy consumption, endothermic chemical recovery and exothermic chemical The recovery was completed in different reverberators, the potential was not used, and the production of 1 ton of titanium consumes 6945kW·h; (3) labor: labor intensity is large, the response needs to be carried out in a vacuum and maintenance atmosphere, and the process is not continuous , Intermittent operation; (4) expensive materials: Mg and TiCl4 account for about 71% of the cost; (5) large environmental load: TiCl4 and Cl2 are highly corrosive, the production process needs to be carried out in a closed system, and no leakage is allowed, Therefore, the equipment investment is relatively large. Half a century later, this skill has not undergone a fundamental change. It is still produced intermittently and fails to complete the successive production, so the production cost is very high.
In recent years, with the increasing shortage of high-grade iron ore resources, the low-grade refractory and the use of multi-element symbiotic ore have become the primary development direction of coal-based direct recovery. The method of recovering and melting carbon-containing pellets to produce granular iron fits these special Demand for comprehensive use of ore. The method of preparing iron particles with low carbon content carbon-containing pellet recovery low temperature smelting is based on the carbon-containing pellets rotary hearth furnace recovery melting technology and rotary kiln particle iron skills. The low carbon content carbon content is selected The pellets make FeO participate in the slag formation reaction, the melting temperature drops to about 1300 ℃, and the mass fraction of iron produced at a lower temperature is 94%-95% of high-quality iron particles. Because iron particles are used as steel-making materials, the content of titanium rods is a limiting factor for the quality of molten steel. It is necessary to satisfy the basic needs of electric furnace steelmaking.
Because the titanium carbon oxide has conductivity within a certain range of ingredients, it can be used for electrolytic dissolution of the anode to obtain metallic titanium on the cathode together. USTB skill selects the soluble anode material containing titanium as the titanium source to produce high purity titanium by electrolysis. The detailed skills are divided into carbon thermal recovery and molten salt electrolysis. The preparation of soluble anode TiCxOy in the skill is based on TiO2 and graphite, mixed with a certain stoichiometric ratio constraint, and the sintered block material is sintered at a certain heat treatment temperature to obtain soluble anode material TiCxOy. The prepared block material is connected as an anode, and electrolysis is carried out in molten salt. In the process of electrolytically preparing titanium metal, anode materials and cathode metal commodities are scattered in different sections of the electrolytic cell. When the anode reverbs, the titanium ions dissolve into the molten salt, and then migrate to the cathode adjacent to the cathode and accumulate at the cathode interface under the electrical effect to obtain the metal titanium. The analysis results show that the oxygen content of the electrolytic titanium is less than 300×10-6, the carbon content is less than 700×10-6, and the cathode current power can reach 89%. The USTB technology prepares TiCxOy solid solution through carbon heat recovery, and then handles the tedious production of TiC and TiO alone, and controls the components of TiCxOy solid solution together to ensure the continuous progress of electrolysis. This method has entered the mid-term experiment period.
According to the low-carbon ratio carbon-containing pellet recovery low-temperature smelting preparation of granular iron skill thinking, the distribution of titanium rods in the recovery process of carbon-containing pellets and the action of titanium rods were experimentally discussed. The results show that the primary factors that affect the mass fraction of titanium rods in commercial iron pellets are carbonaceous bedding, the amount of titanium rods guessed in the pellet mass, and the residence time of the iron pellets in the furnace after melting. In order to reduce the mass fraction of titanium rods in iron particles, the amount of titanium rods brought into the coal powder and iron ore should be restrained as much as possible. It is necessary to select carbonaceous bedding with a low amount of titanium rods, and try to shorten the residence time of iron particles in the furnace after smelting. Mixing the appropriate titanium-fixing rods in pad guessing is helpful to reduce the mass fraction of titanium rods in the iron particles. The addition of CaO to the pellets did not show the effect of detitanium rods, but the mass fraction of titanium rods in the iron particles was slightly added. The addition of the carbon ratio in the pellets will result in the addition of the amount of titanium rods carried by the coal powder in the carbon-containing pellets, so the addition of the carbon ratio will slightly improve the mass fraction of the titanium rods in the iron particles.