Industries
Foundry Industry
Binding agent for green sand molding systems in metal casting. Improves mold strength, surface finish, and thermal stability. Reduces casting defects and enhances production efficiency. Premium foundry-grade bentonite meeting international metallurgical standards.
Key Applications
How Bentonite is Used
Green Sand Molding (Foundry Grade Bentonite)
Sand Binding Bentonite clay creates ionic bonds with silica sand grains in the presence of water, forming a cohesive, moldable aggregate known as green sand. Around 70% of worldwide casting production uses bentonite-bonded sand for making molds — the most proven and cost-effective method in the foundry industry.
Mold Strength & Stability Sodium bentonite provides superior wet and dry compressive strength to molds, preventing collapse during metal pouring. High swelling capacity ensures tight bonding in the water condensation zone, critical for dimensional accuracy and surface finish of castings.
Thermal Stability Bentonite withstands temperatures up to 1300°C during metal pouring without catastrophic degradation. The clay binder forms a slag bond during firing that reinforces mold integrity, allowing consistent casting quality for both ferrous and non-ferrous metals.
Green sand composition:
- Silica sand: 75–85% by mass
- Bentonite clay (binder): 5–11%
- Water (moisture): 2–5%
- Carbonaceous additives (sea coal, anthracite): 2–5%
- Other additives (cereal binders, iron oxide): < 1%
Target customers: Iron and steel foundries, non-ferrous casting plants (aluminum, copper, brass), automotive parts manufacturers, heavy machinery casting facilities, precision casting workshops.
Iron Ore Pelletizing (Pelletizing Grade Bentonite)
Pellet Binder Sodium bentonite is the primary binder in iron ore pelletization, transforming fine iron ore concentrates into spherical pellets (8–16 mm) suitable for blast furnaces and direct reduction plants. The clay absorbs moisture, promotes balling, and creates mechanical bridges between ore particles during agglomeration.
Green & Dry Pellet Strength High water absorption (8–15 times dry mass) and swelling capacity of bentonite improve green, drop, and dry strengths of pellets — preventing collapse during transport to the kiln. Drop number above 4 (industrial minimum) is consistently achieved with proper bentonite dosage.
Fired Pellet Performance During induration at 1200–1300°C, bentonite acts as a low-melting silicate that wets particles and forms slag bonds, boosting cold compressive strength (CCS) above 250 kg/pellet. Pellet Fe content typically reaches 62–66%.
Typical dosages:
- Bentonite dosage: 0.5–1.5% by weight of iron ore concentrate
- Pellet diameter: 8–16 mm
- Firing temperature: 1200–1300°C
- Target CCS (fired): ≥ 250 kg/pellet
- Target drop number (green): ≥ 4 drops from 460 mm
Target customers: Iron ore pelletizing plants, steel mills with captive pellet production, mining companies producing iron ore concentrates, DRI (direct reduced iron) producers.
Mold Coatings & Specialty Applications (Activated Bentonite)
Lustrous Carbon Formation Bentonite blended with mineral coal (lustrous carbon former) creates a thin shiny carbon layer around silica grains during casting. This facilitates clean mold separation at shakeout, reduces scrapping rates, and improves cast surface quality.
Sand Reclamation Proper bentonite quality extends the reuse cycle of foundry sand. High-montmorillonite bentonite maintains binding properties through multiple molding cycles, reducing new sand consumption by 20–30% and lowering waste disposal costs.
Low-Emission Casting Activated bentonite with reduced volatile content minimizes emissions of hazardous pollutants (benzene, toluene, xylene) during metal pouring. Helps foundries comply with environmental regulations including EU Industrial Emissions Directive and EPA standards.
Typical formulations:
- Bentonite + mineral coal premix: 8–12% of sand system
- Facing sand bentonite content: 10–15% for premium surface finish
- Sand system refresh rate: 3–7% new bentonite per cycle
- Moisture control range: 2.8–3.5% for optimal compactability
Target customers: Automotive casting foundries (engine blocks, brake discs), precision casting manufacturers, large-scale steel casting facilities, foundry sand suppliers and recyclers.
Our Products
Recommended Products for This Industry
Select the right bentonite grade for your specific application needs.
Benefits
Why Choose Askangel Bentonite
Advantages of Askangel Bentonite for Foundry
High Montmorillonite Content 98.5% montmorillonite delivers maximum green compressive strength and dry bond strength per unit of bentonite added. Competitors from Turkey, India, and China offer 70–85%, requiring 15–30% higher bentonite dosage to achieve equivalent mold properties.
Superior Swelling Capacity Swell index > 24 ml/2g ensures optimal water absorption and uniform distribution throughout the sand system. This translates directly to consistent compactability, reduced sand-related casting defects, and tighter dimensional tolerances.
Low Crystalline Silica Content < 1% free SiO₂ reduces silicosis risk for foundry workers and lowers dust emissions during sand mixing and shakeout operations. Complies with EU Directive 2017/2398 and OSHA workplace exposure limits.
Thermal Stability at Casting Temperatures Askangel bentonite maintains binding performance at temperatures exceeding 1300°C, making it suitable for gray iron, ductile iron, steel, and non-ferrous casting operations without excessive degradation or dead clay accumulation.
Quality Consistency Batch-to-Batch Askangel controls the entire cycle: proprietary deposit → enrichment → activation → drying → grinding. Each batch undergoes laboratory testing for montmorillonite content, swell index, green compression strength, and moisture before shipment.
Flexible Logistics Bulk shipments (rail cars, trucks), big bags (500 kg, 1000 kg, 1250 kg), 25 kg bags. FOB Poti, DAP to your warehouse, CIF to destination port. Just-in-time delivery programs available for foundries with continuous production schedules.
Applications by Casting Type and Industry
Ferrous Casting:
- Gray iron casting (engine blocks, pipes, machine bases)
- Ductile iron casting (gears, crankshafts, heavy equipment parts)
- Steel casting (valves, pump housings, structural components)
- Malleable iron casting (fittings, hardware, agricultural equipment)
Non-Ferrous Casting:
- Aluminum casting (automotive components, aerospace parts)
- Copper and brass casting (plumbing fittings, decorative elements)
- Bronze casting (bearings, bushings, marine hardware)
Iron Ore Pelletizing:
- Blast furnace pellet production (integrated steel mills)
- Direct reduction pellets (DRI/HBI plants)
- Magnetite and hematite concentrate pelletizing
- Iron ore mining operations with captive pellet plants
Automotive & Industrial Manufacturing:
- Automotive parts casting (brake discs, cylinder heads, transmission housings)
- Heavy machinery components (excavator parts, crane elements)
- Railway components (wheels, rail joints, couplings)
- Energy sector casting (turbine parts, valve bodies, pump impellers)
Global Reach
Export Geography
CIS: Russia, Kazakhstan, Uzbekistan, Azerbaijan, Armenia
Applications: green sand molding for ferrous foundries, iron ore pelletizing for steel mills in Ural and Central Asian regions.
Middle East: Turkey, Iran, UAE, Saudi Arabia
Applications: non-ferrous casting for construction and automotive sectors, iron ore pelletizing for emerging steel production facilities.
Europe: Poland, Germany, Romania, Bulgaria, Italy
Applications: automotive casting foundries, precision steel casting, green sand systems for EU-regulated low-emission foundries.
Africa: Egypt, Kenya, Ethiopia, South Africa
Applications: iron and steel foundries serving construction and mining equipment sectors, pelletizing for growing iron ore extraction operations.
Need Technical Support?
Our team of experts is ready to help you find the right solution for your application.
Contact Us