What to know about titanium sponge
Titanium sponge is an important raw material used in the production of titanium alloys and other titanium products. So how is titanium sponge generated? Here is a brief introduction:
1. How is titanium sponge produced:
Refining titanium ore: The production of titanium sponge usually starts from titanium ore (such as ilmenite, rutile ore, etc.). First, the titanium ore undergoes ore beneficiation and crushing to extract high-grade titanium ore.
Chloride leaching: Titanium ore usually contains oxides and small amounts, so it needs to be leached by chloride to extract titanium. In this step, the ore reacts with chlorine gas to generate titanium chloride gas (TiCl4).
Titanium chloride gas purification: Titanium chloride gas needs to be purified to achieve its purpose. Technologies such as condensation and improvement are usually used to purify titanium chloride gas.
Generation of reduced titanium sponge: The purified titanium chloride gas reacts with pure magnesium powder or other agents at high temperature to generate titanium sponge. In this step, titanium sponge is produced in powder or block form.
Processing of titanium sponge: Titanium sponge is usually generated in small amounts and requires further processing, such as oxidation, impurity removal, refining, etc., to meet the requirements of titanium sponge products.
2. Titanium sponge processing process:
⑴ Chlorination process. Titanium tetrachloride is the main raw material for the production of titanium sponge. At present, there are three main preparation methods: boiling chlorination, molten salt chlorination and shaft furnace chlorination.
The boiling chlorination method is currently the main method for producing titanium tetrachloride. Boiling chlorination is a method that uses fine-grained titanium-rich materials and solid carbonaceous (petroleum coke) reducing agent to perform a chlorination reaction in a fluidized state under the action of high temperature and chlorine gas flow to produce titanium tetrachloride. After decades of research and development, this method has a mature production process and is widely used at home and abroad.
Molten salt chlorination is a method of preparing titanium tetrachloride by suspending finely ground titanium slag or rutile and petroleum coke in a molten salt (main components are KCl, NaCl, MgCl2 and CaCl2) medium, and passing in chlorine gas.
Shaft furnace chlorination involves finely grinding titanium chloride slag (or rutile) and petroleum coke, adding a binder, mixing them to form briquettes, and then coking them. The resulting briquettes are stacked in a vertical chlorination furnace. The method of reacting with chlorine gas in the solid layer state to produce titanium tetrachloride is also called fixed layer chlorination or pellet chlorination. This method has been basically eliminated due to low output and low product quality.
⑵ Refining process
The refining and purification of titanium tetrachloride mainly includes the use of distillation to remove high-boiling point impurities and low-boiling point impurities, and the use of chemical methods to remove vanadium impurities.
For the distillation of titanium tetroxide, my country has long used a high-efficiency float valve distillation tower, and the effect is very good.
As for the vanadium removal method, copper wire has been used to remove vanadium in the past. However, there are problems such as large copper wire consumption, high cost, and high labor intensity. This method is currently being gradually eliminated. Vanadium removal from aluminum powder is a better method with low cost and no waste water. The vanadium removal slag can also be used to extract vanadium, which is being promoted in China.
⑶ Reduction-distillation process
The reduction-distillation method is used to produce titanium sponge. There are two commonly used combination processes: "I-type combination method" and "∩-type combination method". The I-type joint method is also called the series method, and the ∩-type joint method is also called the parallel method. Both methods have their unique advantages and are used in our country.
⑷ Electrolytic magnesium process
At present, foreign titanium sponge factories have widely used multi-polar electrolyzers and separator-free magnesium electrolyzers. However, domestic electrolytic magnesium technology is relatively backward, resulting in high power and chlorine consumption in the production of titanium sponge. Therefore, in recent years, new domestic factories have adopted advanced large-scale multi-pole electrolyzers and separator-free magnesium electrolyzers, and production technology has been greatly improved.
At present, my country's titanium sponge production capacity ranks first in the world. However, compared with the international advanced level, there is still a certain gap in production scale, production technology and product quality . The task of truly reaching the international advanced level is still very arduous.
