Analysis of Differences Between Graphitized Petroleum Coke and Semi Graphitized Petroleum Coke

Introduction:

In the steelmaking or ironmaking process, factors such as product performance, raw material ratio, smelting time, holding time, and superheating time can cause the carbon content in the molten steel (or iron) to fall short of the theoretical value. To compensate for this carbon deficit, carbon-containing substances called carbon enhancers are added. With increasing demands for higher-quality steel, the requirements for carbon enhancers have also become more stringent. To avoid contamination of the molten steel, carbon enhancers need to have a high fixed carbon content and low levels of ash, volatile matter, nitrogen, sulfur, and other harmful impurities.

What is Graphitization?

Graphitization refers to the process where carbon atoms rearrange into the microscopic form of graphite under certain high-temperature conditions. Petroleum coke products start to graphitize at temperatures above 1700°C. Graphitization reduces impurities in the carbon enhancer, increases its carbon content, and lowers sulfur content.

Graphitized Petroleum Coke Carburizer:

• Also Known As: High-temperature graphitized carbon enhancer.
• Production: Made from petroleum coke and subjected to high-temperature graphitization.
• Characteristics: High carbon content, low sulfur, low nitrogen, minimal harmful impurities, and high absorption rate.
• Applications: Preferred for improving steelmaking processes and quality, especially in smelting low-nitrogen steel, steel cord, high-strength tire bead steel wire, and other specialized steels. Widely used in casting, brake pads, and friction materials. Particularly suitable for electric furnace smelting, significantly increasing scrap steel use and reducing or eliminating pig iron usage, with absorption rates over 90%.

Semi Graphitized Petroleum Coke Carburizer:

• Also Known As: Medium-temperature graphitized carbon enhancer.
• Production: Produced as an insulating layer in the high-temperature graphitization process of the Acheson furnace, with calcination temperatures ranging from 1700-2700°C.
• Characteristics: High fixed carbon content, fast dissolution, high absorption rate, moderate sulfur content, and cost-effective.
• Applications: Commonly used in foundries for its cost-effectiveness and efficiency as a carbon enhancer.

Comparison of Key Factors:

1. Physical and Chemical Properties:

GPC Carburizer: Higher fixed carbon content, lower sulfur and nitrogen, darker color, easily marks white paper.

Semi GPC Carburizer: High but comparatively lower fixed carbon content, higher sulfur content, lighter color, does not mark white paper as deeply.

2. Production Process:

2. Price:

GPC Carburizer: More expensive due to superior quality and lower impurity levels.

Semi GPC Carburizer: Cheaper, approximately 1000 yuan/ton less, making it a cost-effective choice for general foundry applications.

Technological Developments:

Since E.G. Acheson invented the graphitization furnace in 1895, the technology has advanced significantly. Modern graphitization furnaces include DC and AC furnaces, continuous graphitization furnaces, and internal string graphitization furnaces. These advancements have improved the efficiency and quality of the graphitization process, enabling the production of high-quality carbon enhancers.

Both Graphitized and Semi Graphitized Petroleum Coke Carburizer are crucial in the steelmaking and foundry industries. The choice between the two depends on the specific requirements of the production process, such as the desired carbon content, acceptable impurity levels, and cost considerations. Graphitized Petroleum Coke Carburizer offer superior quality and lower impurity levels, making them ideal for high-end steel production, while Semi Graphitized Petroleum Coke Carburizer provide a cost-effective alternative for general foundry applications.

Keywords: GPC, Ferroalloy, Graphitized Petroleum Coke, Semi GPC, Carburizer