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How Graphitized Petroleum Coke Achieves a Surge in Absorption Rate from 75% to Over 95%, Enabling “Complete Resource Utilization”
Graphitized petroleum coke has achieved a breakthrough in raising its absorption rate from 75% to over 95% through five core processes: raw material selection, high-temperature graphitization treatment, precise particle size control, process optimization, and circular utilization. This “complete resource utilization” approach can be summarized as follows:
1. Raw Material Selection: Controlling Impurities at the Source
- Low-sulfur, low-ash raw materials
High-quality petroleum coke or needle coke with sulfur content <0.8% and ash content <0.5% is selected. Low-sulfur raw materials prevent sulfur from forming sulfur dioxide gas at high temperatures, reducing carbon loss, while low ash minimizes interference from impurities during melting. - Raw material pretreatment
Through crushing, grading, and shaping processes, large particles and impurities are removed to ensure uniform particle size, laying the foundation for subsequent graphitization.
2. High-Temperature Graphitization Treatment: Restructuring Carbon Atoms
- Graphitization process
Using an Acheson furnace or internal series graphitization furnace, raw materials are treated at temperatures above 2,600°C. This transforms carbon atoms from a disordered arrangement into an ordered lamellar structure, approaching the crystal lattice of graphite and significantly enhancing carbon reactivity and solubility. - Sulfur removal
At high temperatures, sulfur is expelled as sulfur dioxide gas, reducing sulfur content to 0.01%–0.05% and avoiding negative impacts on steel strength and toughness. - Porosity optimization
Graphitization creates a porous structure within carbon particles, increasing porosity and providing more channels for carbon dissolution in molten iron, accelerating absorption.
3. Precise Particle Size Control: Matching Melting Requirements
- Particle size grading
Particle size is controlled within 0.5–20 mm based on melting equipment type (e.g., electric arc furnaces or cupolas) and process requirements:- Electric furnaces (<1 ton): 0.5–2.5 mm to prevent oxidation from overly fine particles.
- Electric furnaces (>3 tons): 5–20 mm to avoid dissolution difficulties from overly coarse particles.
- Uniform particle size distribution
Screening and shaping processes ensure consistent particle size, reducing absorption rate fluctuations caused by size variations.
4. Process Optimization: Enhancing Absorption Efficiency
- Addition timing and methods
- Bottom addition method: In medium-frequency electric furnaces, 70% of the carbon raiser is placed at the furnace bottom and compacted, with the remainder added in batches mid-process to minimize oxidation losses.
- Batch addition: For electric furnace smelting, carbon raisers are added in batches during charging; for cupola smelting, they are added simultaneously with furnace charge to ensure full contact with molten iron.
- Melting parameter control
- Temperature control: Maintaining melting temperatures at 1,500–1,550°C promotes carbon dissolution.
- Heat preservation and stirring: Holding for 5–10 minutes with moderate stirring accelerates carbon particle diffusion and prevents contact with oxidizing agents like iron rust or slag.
- Composition adjustment sequence
Adding manganese first, then carbon, and finally silicon reduces the inhibitory effects of silicon and sulfur on carbon absorption, stabilizing carbon equivalence.
5. Circular Utilization and Green Manufacturing: Maximizing Resource Efficiency
- Waste electrode regeneration
Spent graphite electrodes are regenerated into carbon raisers with a recovery rate of 85%, reducing resource waste. - Biomass-based alternatives
Experiments using palm shell charcoal as a substitute for petroleum coke enable carbon-neutral smelting and reduce reliance on fossil feedstocks. - Smart control systems
Online carbon content monitoring via spectral analysis and 5G IoT-based precise feeding (error <±0.5%) optimize production processes and minimize over-addition.
Technical Outcomes and Industry Impact
- Improved absorption rate: Through these measures, the absorption rate of graphitized petroleum coke carbon raisers has increased from 75% (traditional calcined petroleum coke) to over 95%, significantly enhancing carbon utilization efficiency.
- Enhanced product quality: Low sulfur (≤0.03%) and low nitrogen (80–250 PPM) characteristics effectively prevent casting porosity defects and improve mechanical properties (e.g., hardness, wear resistance).
- Environmental and economic benefits: Carbon emissions per ton of carbon raiser are reduced by 1.2 tons, aligning with green manufacturing trends. Meanwhile, higher absorption rates reduce carbon raiser consumption, lowering production costs.
By implementing end-to-end refined control, graphitized petroleum coke achieves “complete resource utilization,” providing the metallurgical industry with an efficient, low-carbon carbon-raising solution and driving the sector toward high-quality, sustainable development.
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Post time: Mar-31-2026