Green Sand Preparation System

A green sand production line is a complete system designed for preparing wet-type clay-bonded molding sand, widely used in sand casting for iron, steel and non-ferrous alloy castings. The line continuously mixes raw sand, clay (bentonite), coal dust, water and other additives at preset ratios to produce molding sand with excellent flowability, compactability and permeability for automatic or manual molding processes.

"Green Sand" does not refer to the color of the sand. Instead, it indicates that the mold is in a wet (unbaked or uncured) state. In the foundry industry, the term "green" denotes an uncured, wet condition. Therefore, clay-bonded sand is standardly referred to as green sand in English.

The typical process flow includes: raw sand feeding → used sand recovery and treatment → magnetic separation for iron removal → metered addition of clay/coal dust/additives → water addition and mulling → conditioning (adjusting compactability and moisture) → sand discharge → molding → pouring → shakeout → used sand cooling → sand recycling. The entire process is automatically controlled by a PLC system to ensure consistent molding sand quality.

The green sand production line is suitable for green sand casting processes, including horizontal parting molding (e.g. static pressure molding, jolt-squeeze molding) and vertical parting molding (e.g. DISA lines), meeting production requirements from simple small castings to complex large castings.

The main equipment includes drum coolers/sand coolers, vibrating conveyors, magnetic separators, bucket elevators, mixers (muller-type or rotor-type), automatic dosing systems (for clay/coal dust/water metering), online compactability/moisture controllers, PLC control systems, dust collection systems and pneumatic conveying systems.

Our green sand mixers are available in various models with mixing capacity ranging from 10 tons/hour to 200 tons/hour, customizable based on the production rhythm of the customer's molding line and the sand-to-metal ratio.

The production line is equipped with online moisture and compactability controllers that monitor sand parameters in real time during mixing, automatically adjusting water addition and mulling time to maintain compactability within 35%–45% and moisture content within 2.5%–4.0%, ensuring consistent sand performance.

With a comprehensive used sand treatment system (including cooling, magnetic separation, screening and dust collection), the sand recovery rate can reach 90%–95%. An efficient reclamation system not only reduces the cost of new sand purchases but also minimizes solid waste emissions, in line with green foundry requirements.

The entire production line is fully automated with PLC and host computer centralized control, featuring recipe management, automatic dosing, real-time monitoring, data logging, fault diagnosis and alarming functions. The intuitive and user-friendly interface significantly reduces reliance on operator experience and ensures consistent sand quality from batch to batch.

Key factors include effective bentonite content (directly affects bond strength and hot/wet tensile strength), moisture content (too high causes sand sticking, too low increases brittleness), compactability (reflects plasticity and moldability), permeability (affects gas porosity defects) and effective coal dust content (determines surface finish of castings). Our online monitoring and control system provides real-time measurement and automatic adjustment of these parameters.

Daily maintenance includes regularly checking the wear condition of mullers/rotors and scrapers; cleaning residual sand accumulation inside the mixer; checking the lubrication system; periodically calibrating moisture and compactability meters; inspecting the operating status of conveying belts and bucket elevators; and ensuring the dust collection system is functioning properly. We recommend establishing a routine inspection and maintenance log system.

Bentonite should be stored in a dry, well-ventilated warehouse to prevent moisture absorption and agglomeration, which could affect metering accuracy and mixing performance. Coal dust should be kept away from fire sources and stored in a cool, dry place with fire and explosion prevention measures. We recommend using sealed silos with pneumatic conveying to minimize dust pollution and manual handling.

Please provide the following information and we will tailor a solution for you: molding line type and production rhythm (molds/hour), average sand-to-metal ratio, sand consumption per mold, annual production capacity requirements, existing workshop dimensions and height, used sand treatment method and environmental compliance requirements.

Yes. We offer turnkey services from equipment foundation design, installation, piping connection, electrical wiring and system commissioning to operator training. Our engineering team can go to the customer's site to guide installation and commissioning, and provide systematic training on operation and maintenance to ensure a fast start-up and stable operation of the production line.

The production line is equipped with a high-efficiency baghouse dust collection system that provides centralized dust removal at all dust-generating points such as shakeout, conveying and mixing. The dust emission concentration can be controlled below ≤10mg/Nm³, exceeding national environmental standards. In addition, the used sand reclamation system significantly reduces solid waste emissions, enabling clean production and resource recycling.

Key safety precautions include: emergency stop devices on conveying equipment (belt conveyors, bucket elevators) must be fully functional; never insert hands or tools into the mixer during operation; the dust collection system should be regularly cleaned to prevent clogging; all rotating parts must have safety guards; operators should wear dust masks and protective goggles. We provide a complete safety operation manual and warning signs.