The main differences between reduction ironmaking and electric furnace melting of cast iron are as follows:

Principle
Reduction ironmaking: It is the process of reducing iron oxides in iron ore into metallic iron using a reducing agent. For example, in blast furnace ironmaking, coke is used as fuel and reducing agent. At high temperature, carbon monoxide reduces the iron in iron ore (mainly iron oxide) and generates carbon dioxide at the same time.
Electric furnace melting of cast iron: It uses electric current to heat and melt metal raw materials such as scrap iron and pig iron through resistance heating or induction heating to make cast iron. This process is mainly a physical change, and there is no chemical reaction to reduce iron.
Raw materials
Reduction ironmaking: The main raw materials are iron ore, coke, limestone, etc. Iron ore provides a source of iron elements, coke is used to provide heat and as a reducing agent, and limestone is used to use calcium oxide produced by high-temperature decomposition to convert impurities in iron ore into slag for removal.
Electric furnace melting of cast iron: The main raw materials are scrap iron, pig iron, recycled materials, etc. These raw materials are already metal materials with a high iron content, which can be directly melted and then mixed to cast the required cast iron parts.
Equipment
Reduction ironmaking: The main equipment is the blast furnace, which is a tall vertical cylindrical furnace with a multi-layer structure inside, used to complete the reduction, melting and slag iron separation of iron ore.
Electric furnace melting cast iron: Common equipment includes electric arc furnace and induction furnace. The electric arc furnace heats the charge through the electric arc generated between the electrode and the charge; the induction furnace uses the principle of electromagnetic induction to generate eddy currents in the charge to make it heat and melt.
Product quality
Reduction ironmaking: The carbon content of the molten iron produced is relatively low and the impurity content is high. It generally needs further refining before it can be used to produce high-quality steel products.
Electric furnace melting cast iron: The composition and temperature of the molten iron can be controlled more accurately, and the quality of the cast iron produced is more uniform and stable, which can better meet the production of castings with different performance requirements.
Cost and environmental protection
Reduction ironmaking: It requires a large amount of coke and iron ore, which is costly. At the same time, it will produce a large amount of carbon dioxide, waste gas and waste slag, which will cause great pollution to the environment.
Electric furnace melting cast iron: The cost of electricity is high, but the cost of raw materials is relatively low, and there is less waste gas emission during the production process, which has little pollution to the environment.
The following are the application scenarios of reduction ironmaking and electric furnace melting cast iron:
Reduction ironmaking
Raw materials for producing high-quality steel and special steel: Direct reduced iron has few impurities and low sulfur and phosphorus content. It can be used as high-quality pure raw materials for the production of high-quality steel and special steel to meet the high performance requirements of steel applications, such as high-end parts production in aerospace, automobile manufacturing, machinery manufacturing and other fields.
Casting ferroalloys and powder metallurgy: Provide high-purity iron raw materials for casting ferroalloys to ensure the performance of ferroalloys; used in powder metallurgy, it can improve the strength, toughness and other properties of products, and meet the manufacturing needs of electronic components and precision machinery parts.
Applicable to specific resource areas: In areas where natural gas or hydrogen resources are abundant and cheap, the use of gas-based reduction ironmaking can reduce costs and make full use of local resource advantages to achieve iron production.
Electric furnace melting cast iron
Small and medium-sized cast iron parts production: Suitable for small and medium-sized cast iron enterprises, production can be flexibly arranged to meet the needs of multi-variety and small batch cast iron parts, such as the production of various mechanical parts, auto parts, hardware tools, etc.
High-quality cast iron production: It can accurately control the composition and temperature of molten iron to produce cast iron with uniform and stable quality, which is used to manufacture cast iron parts with strict performance requirements, such as engine cylinders, machine tool beds, etc.
Scrap metal recycling: Using scrap iron, pig iron, etc. as raw materials, it can realize the recycling and reuse of scrap metal resources, reduce production costs, and reduce the exploitation of natural resources, which is in line with the concept of sustainable development.
What are the advantages and disadvantages of melting cast iron in an electric furnace?
Advantages
Easy to control temperature: It can accurately control the temperature to meet the requirements of different cast iron materials for melting temperature, which is conducive to the production of high-quality and stable performance cast iron parts, such as accurately melting the molten iron required for ductile iron.
Precise composition: The composition of molten iron can be accurately adjusted according to demand. By selecting different charge ratios and adding alloying elements, the chemical composition of cast iron can be effectively controlled to produce cast iron products with various properties.
Pure molten iron: No coke is used to avoid impurities in coke from mixing into molten iron, making the molten iron purer, reducing the content of harmful elements such as sulfur and phosphorus, and improving the quality of cast iron.
Environmental protection and energy saving: Compared with some traditional smelting methods, such as cupola smelting, electric furnace smelting has less waste gas emissions and less environmental pollution; and the energy utilization rate is high, which can effectively reduce energy waste.
Strong flexibility: Production can be flexibly arranged, suitable for the production of multiple varieties and small batches of cast iron parts, and production tasks can be quickly adjusted to meet the needs of different customers.
Disadvantages
High cost: Electric furnace equipment investment is large, and transformers, electrodes, etc. need to be equipped, and the power consumption is large, the electricity cost is high, and the production cost of cast iron is increased.
High tendency to overcooling: Molten iron has a large tendency to overcool, which is easy to produce D and E type graphite that affects the mechanical properties of the material, resulting in reduced strength and toughness of the casting.
Poor inoculation effect: The molten iron is pure, the heterogeneous crystal core is less, the inoculation effect is poor, and the casting strength is low and the iron is hard under the same composition. It is necessary to increase the amount of inoculant and optimize the inoculation process.
Large shrinkage tendency: The shrinkage tendency is large. When the manganese content in high-grade gray cast iron is high, it is easy to produce micro-shrinkage holes, shrinkage and other defects, which affect the density and mechanical properties of the casting.
Low production efficiency: Generally, continuous smelting is not possible. Compared with continuous smelting equipment such as cupolas, the production efficiency is low and it is not suitable for large-scale and high-efficiency cast iron production.