The formation of the electrode industry, the maintenance and expansion of this industry are possible only in countries with developed economies. The first states to create this sector were Germany, the USA, and Japan. Following them, the production of electrodes began in the USSR.
Industry value
Electrode production is one of the most important business sectors. It ensures the economic independence of the state. The electrode industry acts as an integral element of the heavy industry - ferrous and non-ferrous metallurgy, aviation, engineering, electrical and electronics, nuclear energy and many other industries. In this case, it is worth citing Japan as an example. During the crisis, this country, having eliminated the production of aluminum, redirected resources to the conservation and development of the electrode industry. As a result, today in the country there are more than 100 enterprises in this industry. Domestic manufacturers, despite the significant difficulties associated with reducing product consumption, continue to be in the leading positions among the CIS countries. Currently, the market has created quite fierce competition between foreign and Russian manufacturers. In these conditions, two main circumstances are put forward in the first place. First of all, the cost of production is important. It, in turn, affects the permissible minimum selling price. The second circumstance is the quality that electrodes for welding, blocks for furnaces, structural graphites and other products possess. In this case, we are talking about what are the specific results of their use - what is the specific consumption, how much the products will serve.
The main component of cost and quality
The formation of these indicators is influenced by many factors. Among them are the costs of transport, materials, process fuel, labor, electricity and so on. All these costs account for more than 80% of the cost of production. Raw materials for the electrode industry is one of the most important factors. It affects not only the cost, but also the quality of the products. In this regard, the raw material base of industry acts as one of the indicators of economic and technical competitiveness.
Material Consumption Pattern
It is determined in accordance with the main range of manufactured products in Russia. In particular, domestic enterprises produce:
- Graphite electrodes for electric steel furnaces.
- Carbon graphite cathode blocks.
- Electrodes and weights for the production of silicon and aluminum.
- Structural graphites for various industries.
- Electrodes for arc welding and so on.
The main types of raw materials
Domestic enterprises use various materials. The most common are:
- Petroleum Coke. It can be of special or ordinary quality.
- Shale coke and needle structure.
- Technological anthracites.
- Coal tar pitch.
Difficulties with materials
Today in Russia there are no enterprises producing low-sulfur petroleum coke. About 200 thousand tons of raw material turned out to be outside the country in Turkmenistan, where its production for some reason decreased. Today, the creation of hydrotreatment plants for coking raw materials at oil refineries is considered an urgent option. This will allow organizing the release of material with a reduced sulfur content in the Russian territory. But the implementation of deep oil refining projects and the necessary reconstruction of many refineries require a reduction in the volume of coking feedstock. The needle-like material is purchased primarily abroad. The main suppliers are the United States and Japan. This raw material for the electrode industry was produced by the domestic Novoufimsky refinery. This enterprise has shown real possibilities both in the required volume and in the required product quality. At first, experimental and then industrial batches of material were produced. The volume of output left 1.5 thousand tons. Today it depends on the regularity of supplies of low-sulfur scarce oil. Some enterprises show fairly stable results in the production of materials. So, in recent years, to a certain extent, the quality of coal tar pitch has stabilized. However, not all involved enterprises have launched the production of grades “A” and “B”. It is this raw material for the electrode industry that is of particular importance, which is reflected in the number of orders for it. There is no stability in the release of other important materials. For example, this applies to pyrolysis pitch, which can act as an additive in coal. In individual process steps, these components are essential. There is no release of coal tar pitch (grade "T"). It is necessary to obtain some structural materials of the carbon type.
The state of domestic enterprises
Reduced attention to the problem of the supply of raw materials for the electrode industry caused a shortage of carbon material and an increase in imports from 35 to 100%. So, the untimely preparation of sections and quarries of the Kolyvan deposit of technological anthracite deposits located in the Novosibirsk region, and the delay of overburden operations by more than 5 years, caused a sharp reduction in the production and enrichment of this raw material. Significant changes have also taken place in the supply of materials for the production of structural graphites. In connection with the cessation of the manufacture of pyrolysis coke in 1992-94. their volume sharply decreased. The emerging acute problem of finding alternative materials required an immediate solution. The Moscow Electrode Plant, and followed by the NEZ (Novocherkassk enterprise) began research and work on the development of manufacturing technology for structural graphites. For this, cooperation was established with the Slate Chemical Plant in Estonia.
Achievements of Russian enterprises
The Chelyabinsk Electrode Plant subsequently also engaged in similar work. As a result of the research, new lines were launched at the enterprise. As a result, ChEZ produced lots of various grades of structural graphite based on pitch coke. Material for them is supplied by domestic enterprises. The characteristics of the graphites obtained correspond to those made using petroleum coke. Thus, the task of supplying various brands of material for a wide range of purposes was solved. In addition, the production and sending to the nuclear power plants of products from structural graphite necessary for the construction and repair of RBMK units has been restored. To complete the development of pitch coke, which acts as a filler in structural graphites, it is necessary to carry out certain technological and technical measures in the process of its preparation and preparation.
Characteristics of materials
In the production of all types of carbon-graphite raw materials, natural and artificial components are used. The main component in them is carbon. Natural materials include natural graphites and anthracites. Artificial components, however, make up the bulk of the carbonaceous feed. Different forms of the main ingredient of the raw material are obtained by the decomposition of organic compounds. They can form from the liquid or gas phase. Their preparation is also possible by decomposition of solid compounds. For example, certain types of soot are formed from the gas phase, and, in turn, from petroleum coke. The starting material and the processing method have a decisive influence on the characteristics of the final product.
All raw materials for the electrode industry can be divided into 2 groups: solid carbon components and binders. Consider them.
Solid materials
1. Anthracite. It acts as the main component of coal blocks and electrodes used in the laying and lining of bathtubs, furnaces, etc. The main requirements for anthracite are:
- Low sulfur content.
- Thermal resistance.
- Low ash content.
- Mechanical strength.
- High conductivity.
The use of anthracite in compositions helps to improve the operational characteristics of products, primarily their thermal conductivity.
2. Coke. This is one of the most important components for the electro-carbon and electrode industries. Today, two types of this material are produced. The first - oil - is obtained through the coking of oil residues. Its properties depend on the type of source material. Production of this type is carried out in 2 ways. In accordance with the first, coking is carried out in heated metal cubes. The second method is a delayed process in unheated chambers. The second type is obtained through the processing of coal tar pitch.
Graphite
This component is used in most carbon-graphite materials. When graphite is introduced into the mass, its ductility improves, and internal and external friction decreases. This allows you to get more dense electrodes for welding and other products. Even a small amount of graphite (4-6%) positively affects the properties of the product. In particular, its heat resistance, heat and electrical conductivity are increased. The main indicators that determine the quality of graphite grades are particle size distribution and ash content. However, they are sufficient only when it comes to the material of a particular deposit and the manufacturing method. With the same value of indicators, graphites of different origin may have differences in other properties.
Technological process
The delayed method for producing coke is today considered the most popular. The essence of this process is that the material, preheated to 500 degrees, is pumped into unheated reactors isolated from the outside. According to various schemes, from 2 to 4 reactors can be installed in the unit. The temperature in them is 470-480 degrees, and the pressure is up to 1.7 atm. The unit is designed to be filled during the day. After shutting down, the filled reactor is steamed. This is necessary for distillation of distillate oil fractions from the material. They, in turn, are sent to a distillation column.