1. Smelting of White Fused Alumina: White fused alumina (WFA) is produced from industrial alumina powder through high-temperature smelting. It appears white, with a hardness slightly higher than brown fused alumina but with lower toughness. WFA-based abrasives are suitable for grinding high-carbon steel, high-speed steel, and quenched steel. Additionally, it serves as polishing materials, precision casting sand, spray materials, chemical catalysts, special ceramics, and advanced refractory materials.

Smelting Process:

• Electric Arc Furnace: The smelting process is similar to brown fused alumina, performed in an electric arc furnace (EAF), available in single-phase and three-phase configurations, with three-phase being the most common. Transformer capacities range from 1,000 to 10,000 kVA.
• Furnace Types: Depending on the furnace structure, the process can involve fixed, tilting, or flow furnaces.
• Furnace Lining: The lining should offer excellent thermal insulation and preferably good permeability or have dedicated ventilation channels to prevent “explosive” gas release.

Smelting Steps:

1. Startup Phase: Prepare by connecting and adjusting electrodes. Initiate the arc using methods like paper tube, carbon rod, or charcoal. Once the current reaches 20%-50% of the load, add a small amount of material to stabilize the arc, and then gradually increase to 80%, entering the smelting phase.
2. Smelting Phase: This includes two methods:
   1. Closed Furnace (Thick Layer): The arc is covered by a thick material layer, periodically added to maintain coverage.
      1. Open Furnace (Thin Layer): The arc is exposed for longer periods with material layers about 300mm thick, added periodically.
3. Monitor the thickness and melting area using iron rods. Maintain the required feeding rate and ensure stable melting.
4. Control Phase: Cease adding alumina powder to expand the melting area. Use lower voltage and maximum power to raise the surface temperature, forming a “red cover” indicating the end of this phase.
5. Refining Phase: Extend to ensure complete melting and carbon evaporation. Typically, an additional 20-30 minutes of melting is necessary after forming the red cover.
6. Cooling Phase:
   1. Tilting Furnace: Slowly tilt to pour the molten material into a cooling container, using controlled angles to avoid damaging the container.
      1. Fixed Furnace: Move the furnace from the melting zone, cool with water, and then allow natural cooling.
7. Sorting Phase:
   1. Tilting Furnace: Simple grading, with automatic separation of brittle layers.
      1. Fixed Furnace: Complex grading, requiring separation of various grades, leading to higher sorting costs and lower yield.
8. Sorted Primary Blocks: Stored in the finished block area.

2. Granulation of White Fused Alumina:Crushing and Quality Control:

1. Pre-Sorting: Ensure no impurities enter the crushing line by sorting primary blocks before they enter the silo.
2. Density Requirements: Use different crushing methods (Barmac, roller crusher) to adjust bulk density as per customer needs.
3. Intelligent Control: The crushing line processes up to 150 tons of primary blocks daily, monitored via a central control room for machine status and material levels.
4. Granulation Process: Primary blocks pass through various crushers and sieves, undergo multiple magnetic and air wash treatments to meet the required standards.
5. Purity Control: High-power air washers and 8000 Gauss magnetic separators ensure the cleanliness and purity of the sand.
6. Contaminant Control: Ultrasonic vibrating screens remove impurities like wood chips before final packaging.
7. Chemical Composition: Daily chemical analysis of finished sand to ensure compliance.
8. Quality Assurance: Comprehensive testing ensures each batch meets quality standards, with every ton traceable through an intelligent quality control system. Samples are archived with traceability codes for one year.

This refined process ensures high-quality white fused alumina, suitable for various industrial applications, maintaining stringent quality control throughout production.