ECOSIL™
Sand adhesion, surface defects, and mold instability are among the most persistent quality challenges in green sand casting. Each one translates directly into rework, material loss, and production delays.
ECOSIL™ addresses all three with a single, pre-formulated molding sand additive that combines high-quality foundry bentonite (GEKO™) with high-reactivity mineral coal — pre-balanced and homogenized for immediate use.
As the formulation reaches casting temperature, the mineral coal component generates a thin, continuous lustrous carbon layer that isolates the mold sand from the liquid metal. This protective barrier prevents metal penetration into the sand, facilitates mold release, and produces smooth, high-precision cast surfaces — while the bentonite component ensures mold strength, compactability, and dimensional stability throughout the process.
ECOSIL™ eliminates the need for separate dosing and complex additive adjustments, delivering consistent performance batch-to-batch with a single ready-to-use product.
Our unique eco-friendly technology, ECOSIL LE, drastically reduce emissions and help foundries comply with highly demanding environmental regulations and standards. This is our two-tiered Bentonite solution to provide a one-of-a-kind efficient molding system.
Product Information
Superior Cast Surface Quality
- The lustrous carbon layer isolates the metal from the mold sand throughout the casting process, producing smooth surfaces with high dimensional precision. This reduces the need for post-casting finishing operations such as grinding or shot blasting, directly lowering per-part processing costs.
Reduced Sand-Cast Defects
- By creating a continuous protective barrier at the metal-mold interface, ECOSIL™ significantly reduces the occurrence of sand adhesion (burn-on), veining, and other surface defects that are among the most common causes of casting rejection in green sand systems.
Low Emission Technology
- ECOSIL™’s controlled coal specification is engineered to minimize the generation of harmful gases and particulate emissions during casting. This helps foundries maintain compliance with increasingly stringent occupational health and environmental regulations — without compromising surface quality outcomes.
Faster Mold Disintegration and Sand Reclamation
- After casting, the mold breaks down more rapidly, facilitating mechanical shakeout and accelerating the return of sand to the system. Combined with low contamination levels from the controlled formulation, this extends sand system life and reduces the cost of make-up sand additions.
Simplified Dosing and Process Control
- Because ECOSIL™ arrives as a pre-balanced, homogenized blend, foundry operators add a single product rather than managing separate bentonite and coal additions. This eliminates ratio dosing errors, reduces blend adjustment complexity, and simplifies quality control of the sand system.
Shorter Mixing Time and Higher Throughput
- The uniform pre-blend reduces the time required for active mixing to achieve homogeneous sand properties, supporting higher throughput on continuous molding lines without sacrificing compactability or strength targets.
Batch-to-Batch Consistency
- ECOSIL™ is produced to strict physical and functional specifications — including compactability, moisture content, ash content, and methylene blue adsorption — ensuring that each delivery performs identically, reducing the need for sand system rebalancing between batches.
Step 1 — Homogeneous Mixing
The pre-balanced blend ensures uniform distribution of both the bentonite and coal components throughout the sand system from the first mix cycle. Unlike separate additive dosing, a pre-blended system eliminates ratio variability and reduces mixing time, contributing to higher throughput and process consistency.
Step 2 — Optimized Thermal Reaction
As molten metal contacts the mold, the high-reactivity coal generates lustrous carbon at the precise temperature range required for effective layer formation. Reactivity control is critical: insufficient reactivity produces incomplete coverage; excessive reactivity leads to premature burn-off and increased gas generation. ECOSIL™’s controlled coal specification ensures the reaction occurs at the right moment, in the right amount.
Step 3 — Protective Lustrous Carbon Layer
The lustrous carbon forms a thin, continuous film between the silica sand grains and the liquid metal surface. This layer acts as a physical and thermal barrier that prevents metal penetration into the mold, reduces sand burn-on defects, and allows the casting to separate cleanly from the mold without mechanical damage to the surface.
The Result
The end product has significantly improved surface quality in the finished casting — with measurable reductions in sand adhesion, veining defects, and surface roughness — and a mold that disintegrates faster after casting, accelerating sand reclamation and reuse.
Q: What is a lustrous carbon former and why does it matter in green sand casting?
A: A lustrous carbon former is a carbonaceous material — typically mineral coal — that, when exposed to the heat of molten metal, pyrolyzes to produce a thin layer of shiny, graphitic carbon on the surface of mold sand grains. This layer acts as a barrier between the liquid metal and the sand, preventing metal penetration and sand adhesion. The result is smoother cast surfaces, fewer surface defects, and easier mold release. The reactivity and ash content of the coal directly determine how effectively this layer forms at casting temperature.
Q: What is the difference between Ecosil™ and using bentonite and coal as separate additions?
A: When bentonite and coal are added separately to a sand system, their ratio and distribution depend on the accuracy of individual dosing equipment and the mixing efficiency of the muller. Variations in either can lead to inconsistent sand properties, surface quality variation, and defect rates that are difficult to diagnose. Ecosil™ combines both components in a pre-balanced, homogenized blend, eliminating dosing ratio variability as a source of process instability and simplifying quality control to a single product addition.
Q: How does Ecosil™ help foundries reduce emissions?
A: The emissions generated during green sand casting are strongly influenced by the volatile content and sulfur level of the coal additive. Ecosil™ uses a controlled-reactivity, low-sulfur coal specification that generates the minimum amount of gas and particulate necessary to form an effective lustrous carbon layer. This reduces total volatile organic compound (VOC) and SO₂ emissions at the casting station, supporting compliance with environmental and workplace air quality standards.
Q: Does Ecosil™ work with all types of green sand systems?
A: Ecosil™ BR is designed for green sand molding systems using silica sand as the base aggregate. It is compatible with high-pressure and high-density molding lines as well as conventional flask-based systems. The optimal addition rate and sand system parameters should be calibrated based on the specific molding machine, part geometry, alloy, and pouring temperature. Clariant’s technical team can support application assessment and process optimization.
Q: What quality specifications does Ecosil™ meet?
A: Ecosil™ is produced to defined specifications covering moisture content, granulometry, compactability, coal ash and sulfur content, and bentonite performance parameters including methylene blue adsorption, wet tensile strength, green compressive strength, and swelling index. These specifications ensure consistent functional performance across all deliveries. Detailed specifications are available in the product data sheet upon request.
