1. Raw Material Quality
The grade of the raw materials determines how much titanium can be transferred into the alloy. In aluminothermic ferrotitanium production, aluminum particles containing more than 98 percent aluminum are normally used, because the higher the aluminum grade, the stronger the reducing effect and the more complete the reduction of titanium oxides. Ilmenite concentrate and rutile should be screened for grade, moisture and fines before batching.
Lime is added as a flux in the furnace charge. It lowers the melting point of the slag, improves slag fluidity, promotes the sinking of suspended metal droplets, and prevents titanium oxide from combining with aluminum oxide in the slag. A well-fluxed slag shortens the separation time and raises titanium recovery.
2. Unit Thermal Effect
The unit thermal effect is the heat released per unit mass of the charge, and it is the sum of the chemical reaction heat and the physical heat carried in by the charge. The chemical reaction heat is mainly determined by the grade and batching quantity of the ilmenite concentrate, rutile, potassium chlorate and aluminum particles.
Potassium chlorate acts as an oxidizer; its proportion directly changes the reaction heat balance. The physical heat is mainly determined by the roasting temperature of the ilmenite concentrate and rutile. Roasting removes moisture and volatiles, so a hot charge keeps the bath temperature high and keeps the slag fluid.
3. Aluminum Allocation Coefficient
The aluminum allocation coefficient is the ratio of the actual aluminum charge to the theoretical amount required for reduction. Titanium recovery increases as the aluminum charge increases, because more aluminum means more complete reduction of titanium oxide.
However, adding too much aluminum reduces the unit thermal effect of the reaction, thickens the slag, and makes it difficult for the alloy droplets to coalesce and sink. It also risks the aluminum content of the ferrotitanium exceeding the grade limit, which degrades product quality. The operator therefore balances recovery against alloy composition.
4. Practical Control Points
To raise recovery consistently, smelters should keep the aluminum particle grade above 98 percent, roast ilmenite and rutile to a stable temperature, screen fines out of the charge, batch potassium chlorate against the actual reducing demand, and tap the alloy promptly once the slag has separated.
Control moisture in all raw materials.
Calibrate the batching scale before each heat.
Record the recovery rate per heat for trend analysis.
5. Standard and Quality Reference
Finished ferrotitanium should be checked against GB/T 3282, which defines the titanium content ranges and impurity limits for ferrotitanium grades. The titanium content of the alloy and the residual aluminum content are the two properties most affected by the factors described above, so both should be verified on every production lot.
Frequently Asked Questions
Q: What aluminum particle grade is recommended?
Aluminum particles containing more than 98 percent aluminum are generally used for the reduction.
Q: What is the role of lime in the charge?
Lime lowers the slag melting point, improves slag fluidity, promotes sinking of suspended metal, and prevents titanium oxide from combining with aluminum oxide.
Q: What happens if too much aluminum is added?
The unit thermal effect drops, the slag thickens, and the aluminum content of the alloy may exceed the standard limit.
Q: What determines the unit thermal effect?
The chemical reaction heat of the charge and the physical heat carried in by roasted raw materials.
Q: Which standard applies to ferrotitanium quality?
GB/T 3282 defines the composition and inspection requirements for ferrotitanium grades.
