Title: application of large scale titanium slag furnace with graphite electrode research.
Key words: graphite electrode application research, graphite electrode furnace
Abstract:
In order to better evaluate the application of graphite electrode in large scale titanium slag furnace, this paper focuses on the comparison and analysis of ordinary and high-power graphite electrode from the aspects of main parameters of electrode, selective application test of electrode and cost, so as to find the type of graphite electrode suitable for large scale titanium slag furnace.
- Application of graphite electrode in large scale titanium slag furnace:
There are three kinds of titanium slag smelting techniques with graphite electrode in the world. One is the solid electrode adopted by Rio tinto as the representative. Second, hollow electrodes are adopted by NSL company as the representative, and the technology is round hermetic direct-current electric furnace, and continuous charging smelting is adopted. Third, solid electrodes are adopted by Ukraine as the representative, and the technology is round semi-hermetic, and one-time charging smelting is adopted.
Effect of graphite electrode performance index on electrode consumption:
The main indexes of graphite electrode include volume density, resistivity, ash content, thermal expansion coefficient, flexural strength, elastic modulus, etc. Researchers have studied the influence of the main indicators of the graphite electrode on the electrode consumption, showing that the resistivity, volume density and mechanical strength of the electrode are the main factors affecting the electrode consumption.
- Resistivity and electrode consumption the tester once divided the electrodes into four groups according to the size of the resistivity and conducted the steelmaking test in the electric arc furnace. The result was that the electrode consumption increased as the resistivity increased. The reason is that temperature is one of the main factors affecting the oxygenation rate, and the current density is the same, the higher the resistivity, the higher the temperature of the electrode, the faster the oxidation. The higher the temperature of the electrode, the faster the oxidation.
- Volume density and electrode consumption volume density is one of the most important basic properties of graphite electrode. The mechanical strength, elastic modulus and thermal conductivity of graphite electrode increase with the increase of volume density, while the resistance and porosity are opposite. Therefore, the volume density of electrode has a direct effect on electrode consumption. The higher the volume density of electrode, the lower the consumption of stone and ink electrode.
- Mechanical strength and electrode consumption with the increase of mechanical strength, the thermal stress resistance of the electrode increases, so that the electrode consumption caused by electrode fragmentation or fracture decreases. To sum up, the relationship between physical indexes of graphite electrode and electrode consumption shows that electrode consumption decreases with the decrease of electrode resistivity and ash content, while decreases with the increase of electrode mechanical strength and volume density. The relationship between them can provide favorable reference for selecting graphite electrode suitable for large scale titanium slag furnace.
In recent years, the LMM GROUP graphite electrode manufacturer has broken through the production technology and equipment bottleneck of producing large diameter and high power graphite electrode. The resistivity, flexural strength, elastic modulus and volume density of the stone and ink electrodes provided are within the range required by foreign carbon plants, which can meet the requirements of titanium slag smelting.
- Graphite electrode application test research – analysis is suitable for large scale titanium slag furnace production
Graphite electrode is made of petroleum coke and asphalt coke as aggregate and coal asphalt as binder by conventional production process. The quality of graphite electrode mainly depends on three aspects: raw material performance, production equipment and process technology, among which raw material performance is the basic condition. Ordinary power rate graphite electrode is produced by common grade petroleum coke, with low graphitization temperature, so its physical and chemical properties are poor, such as high resistivity, large linear expansion coefficient, poor thermal shock resistance, and less current density allowed to pass. High power graphite is produced with high quality petroleum coke (or low grade needle coke), and its physical and chemical properties are better than ordinary power graphite electrodes, such as low resistivity, allowing for greater current density. As for titanium slag smelting, the application of graphite electrode in large electric furnace is rarely reported in relevant literature or books. In order to better compare and evaluate which type of graphite electrode is more suitable for the production and use of large scale titanium slag furnace, this paper compares and analyzes the main parameters of electrode, selective application test of electrode and cost of electrode
- Application of graphite electrode in large scale titanium slag furnace
The production practice shows that the high power stone-ink electrode is superior to the ordinary graphite electrode in terms of electrode consumption. From the perspective of process equipment, the ordinary graphite electrode should not be used in semi-closed or open electric furnace using continuous feeding, mainly because the oxidation rate of the ordinary graphite electrode is faster than the high power graphite electrode, can not effectively ensure the continuity and stability of the electrode, thus affecting the normal production of the electric furnace.
- According to the electrode application test data, the single consumption of high-power graphite electrode tons of slag electrode is 12.5kg, while that of ordinary graphite electrode tons of slag electrode is 16.0kg. According to the electrode consumption index, high-power graphite electrode is superior to ordinary graphite electrode in oxidation resistance.
- Based on the investigation on the price of graphite electrode, the price of ordinary power stone ink electrode is about 11,000 yuan/ton. Thus, when the price difference between high-power graphite electrode and ordinary power graphite electrode is less than 3080 yuan/ton, the cost of tons of slag of high-power graphite electrode is lower than that of general power graphite electrode.
