Electrode paste is produced from calcined petroleum coke (or calcined pitch coke), calcined anthracite, coal tar pitch and other additional materials. Electrode paste is used for the manufacture of carbon paste electrodes for electric arc furnaces designed for a production of various types of ferroalloys, calcium carbide, etc.
The electrode paste is put into the furnace column in different forms: cylindrical, oval, block, etc. According to different sizes, it is pressed into shape.
Product shape and size:
|Block electrode paste||60*80*10mm|
|Oval electrode paste||50*100mm|
|Column electrode paste||Ø500, Ø600, Ø700, Ø800, Ø900, Ø1000|
The performance and quality of electrode paste in our country are mainly concerned with traditional indicators such as ash, volatile ingredient, resistivity, compressive strength, and bulk density. With the frequent occurrence of “soft break” and “hard break” quality accidents in recent years, coupled with environmental protection requirements, backward production capacity control policies, and the rapid development of large closed submerged arc furnaces, some calcium carbide and ferroalloy manufacturers have required electrode paste quality Gradually not limited to traditional indicators. Some enterprise technical experts and scholars combined with some foreign enterprise electrode paste quality standards to discuss and evaluate some other key technologies such as plasticity, fluidity, softness, thermal shock resistance and other performance indicators. Our country began to implement the new industry standard for submerged arc furnace self-baking electrode paste in April 2015. The formulation of the new standard is conducive to promoting the continuous progress of my country’s electrode paste industry, and it is also conducive to the selection of suitable electrode pastes by various manufacturers in combination with their own different submerged arc furnace conditions. However, we must also see that compared with foreign electrode paste testing standards, my country still has fewer standard items, which cannot fully reflect the performance of electrode paste, and the international competitiveness is not strong enough.
As an important raw material for self-baking electrodes, electrode paste is currently mainly used in the production of calcium carbide and ferroalloys. It is also used in yellow phosphorus and other smelting industries, but it accounts for a relatively small proportion. With decades of development, some furnaces with small sizes, high energy consumption and low efficiency are gradually eliminated. Calcium carbide industry is the foundation of new enterprises. The 40.5MVA enclosed calcium carbide furnace is the main furnace type, and the 81MVA enclosed calcium carbide furnace has also been completed and put into operation. In the ordinary ferroalloy industry, the capacity of newly-built submerged electric furnaces is generally above 25MVA, and 72MVA ferronickel furnaces and 75MVA ferrochrome furnaces have been completed and put into operation in our country.
Electrode paste production improvement and suggestions
1) Further improve the formulation of raw materials, explore new alternative raw materials, and prepare high-quality electrode pastes to meet the needs of large submerged electric furnaces for the preparation of calcium carbide and ferroalloys.
2) Traditional crafts and equipment are gradually unable to meet the needs of industrial environment and technological production. There is still a big gap between technological improvement and technological upgrading and large foreign companies. The automation, information and intelligence of production equipment need to be further improved.
3) At present, many electrode paste manufacturers still adopt the old standards, and they need to further understand the new industry standards. At the same time, they need to further supplement and improve the industry technical standard system to narrow the gap in electrode paste technology quality with large foreign companies and enhance international competitiveness.
The traditional production process of electrode paste mainly consists of raw material calcination, crushing, screening, grinding, kneading and forming. Electrode paste is the raw material for self-baking electrodes, and its baking stage is completed in a submerged electric furnace, so its process does not include baking and subsequent graphitized processes, as shown in the figure.
In recent years, ferroalloy and calcium carbide mine thermo electric furnaces have gradually become large, and environmental protection requirements have also been increasing. These have also put forward higher and higher requirements on the production process and equipment of electrode paste companies. In order to solve these problems, electrode paste manufacturers are exploring technological transformation. In order to save energy and reduce pollution, the waste heat generated by calcination is recycled, thereby reducing costs. Yunnan Aluminum has realized the simultaneous production of carbon block production and electrode paste production through the optimization and partial transformation of the carbon production process for aluminum, which is worthy of promotion. Fang Lixia and others also optimized and analyzed the design of a typical electrode paste conveyor, which provided ideas for the research on the transformation of electrode paste production related equipment.