Examining sand Reclamation Technology.
Deciding to reclaim your sand is only the first step. When focusing on specific equipment for your operation, many different variables loom, such as system type, dimensions and capacity. To make the decision process easier, modern casting offers the following detailed guide of the various thermal and mechanical sand reclamation systems available. In addition, recent installation information is provided to demonstrate the effectiveness of the systems in operation.
An important fact to remember is that the information supplied is only one model of equipment; additional models and system types may be available from the manufacturer. In addition, the machine-specific information was provided by the manufacturer through a survey.
Rotary Lump Crusher/Sand Reclaimer
Didion International, Inc.
Riverside Industrial Centre
7000 West Geneva Drive St. Peters, Missouri 63376
Contact: Mike Didion.
System type: Mechanical.
Drum dimensions: Ranging from 4 x 16 ft to 6 x 30 ft.
Capacity: 1-40 tons/hr.
Key attributes: A serrated-tooth lining offers wear resistance while breaking down large sand lumps and separating metallics from the sand. Automatic recirculation of lumps provides additional scrubbing and higher output percentages, while integral sand screening and fines removal classifies the sand with extremely low cubic ft/mm requirements.
In operation: Vibratory feed conveyors send large sand lumps into the reclaimer. High profile flights screw the lumps forward where they enter the dual chamber attrition section and are reduced to less than 0.375 in. The tramp metal is separated out. The sand then passes through tapered holes in the cast lining to an outer chamber where screening and primary classification occurs. Remaining large chunks automatically are recirculated into the feed conveyor for another pass through the machine. The binder and fines then are removed to a baghouse, leaving only reclaimed sand.
Foundry data: Betz Industries is a nobake molding gray and ductile iron foundry located in Grand Rapids, Michigan. It produces 12 tons of castings/hr for precision automotive dies, patterns and machine beds for the automotive and heavy industries.
Case history: In 1984, Betz Industries purchased a rotary sand reclaimer to begin nobake sand reclamation, and used it in conjunction with pneumatic scrubbers. After learning that the reclaimed sand was acceptable without using the secondary scrubbers, the company employed only the reclaimer, saving on energy, operation and maintenance costs. When Betz Industries expanded in 1999 (doubling the size of its foundry), it installed two new sand reclaimers, increasing production of reclaimed sand to 130 tons/hr. The company now reclaims 97% of its nobake sand, disposing only 3% dust. Reclaiming sand saves the company $4190.40/ hr. "The proven performance and excellent savings is why we continue to use rotary reclamation equipment. Its design is efficient (1 hp/ton) and requires little maintenance,"
R-Series Mechanical Reclamation Systems
Palmer Manufacturing & Supply, Inc.
18 Bechtle Avenue Springfield, Ohio 45504
Contact: Jack Palmer or Lee White.
System type: Mechanical.
Footprint: 9 x 18 ft.
Capacity: 1-10 tons/hr.
Key attributes: The system features an attrition mill with dust hood, feed elevator, screener, surge hopper, flow control valve, classifier and discharge level control.
In operation: The top-loading attrition mill uses a dual-screen agglomeration reduction system comprised of two perforated steel plates. The first is located in the bottom of the mill in the primary chamber and permits only loose sand and small lumps to feed into the secondary chamber. The second screen is located at the discharge flange of the secondary chamber and the discharge housing and allows only grain-size sand to exit. The feed elevator transfers reclaimed sand from the discharge of the attrition mill to the top of the screener hopper where a high-frequency pneumatic vibrator mounted to the screener segregates compound grains. The sand then is fed through the flow control valve to regulate the sand flow into the classifier body so that fines extraction efficiency is constant. After the fines extraction, the reclaimed sand is ready for use.
Foundry data: Midland Manufacturing Co., a producer of copper-based components in Fort Worth, Texas purchased a R-3 Reclaimer in January 2000.
Case history: Midland has converted many of its green sand jobs and tooling to nobake mold boxes as a result of the purchase of a complete nobake molding system in January 2000. The result with the molds is a high sand-to-metal ratio. Coupling this fact with the alloys it pours, Midland is faced with a difficult process to minimize loss-on-ignition (LOI) sand properties. Without additional process changes or equipment, Midland has controlled its LOI, keeping it less than 2% with minimal new sand additions. Further trimming of sand usage per mold, increase of fluidization and dust collection in the classifier, and reductions in binder usage all have contributed to Midland's LOI being on a consistent down slope. Midland is on track to attain a consistent LOI of 1% within the next six months using only mechanical reclamation.
Calcifire Thermal Reclamation System
Dependable Foundry Equipment Co.
P.O. Box 3210
12505 S.W. Herman Road
Tualatin, Oregon 97062
Contact: Bill Zachary.
System type: Thermal.
Footprint: 7 ft 6 in. x 14 ft 7 in.
Capacity: 0.5-5 tons/hr.
Key attributes: A direct-fired fuel bed chamber introduces sand from the top and provides full fluidization wall-towall. It works on both chemically-bonded and clay-bonded sand.
In operation: The binder material combusts in the fluid bed chamber as air and natural gas are introduced through distributor tubes. Heat-resistant steel and ceramic fiber insulation eliminate the need for refractory linings and allow the peak temperature to be reached quickly. Sand flow through the fluid bed easily is regulated for desired effectiveness, resulting in reclaimed sand that is ready to use.
Foundry data: Buddy Bar Casting, Inc., South Gate, California, is an aluminum foundry that specializes in high performance aftermarket automotive components including engine blocks and cylinder heads.
Case history: Buddy Bar recently installed a I ton/hr system. The foundry thermally reclaims sand from phenolic urethane bonded nobake molds. The reclaimed sand includes a percentage of shell cores. Bill Fell, president of Buddy Bar Casting, said he expects to reclaim virtually 100% of the spent sand from the mold and core processes and reduce sand disposal to a small fraction of the current level. In addition to savings in new sand purchases and reduced disposal costs, the foundry expects to achieve thermal stabilization of sand grains to minimize or totally eliminate certain dimensional defects experienced with new sand.
TF-3000 Thermfire Thermal Sand Reclamation System
Gudgeon Thermfire International, Inc.
420 Neptune Crescent
London, Ontario, Canada N6M lAl
Contact: Brent Gudgeon.
System type: Thermal.
Dimensions: 13 ft 8 in. x 8 ft x 15 ft lOin.
Capacity: 1.5 tons/hr.
Key attributes: The reclamation is performed entirely in one machine and can reach working temperature for processing sand from a cold start in 25 mm. The system features two sources of heat recovery, making it thermally efficient and minimizing natural gas usage.
In operation: The sand feeds into the calcining chamber and is elevated to a temperature of 1300F (704C) using an indirect firing method that allows for lower operating temperatures. The temperature is controlled by a thermocouple that feeds data to the PLC, which controls the motorized valves in the gas supply lines. Direct spark ignition and flame rods on the burners detect flames when burning the gas mixture. The thermally reclaimed sand passes over a weir from the calcining chamber into the sand transfer box, which moves the sand to the cooling bed below. The sand temperature is reduced to 8SF (29C) on discharge as fluidizing air travels through it to dissipate the heat.
Foundry data: Arrow Aluminum Castings Co., Avon Lake, Ohio, casts aluminum components using nobake molding and shell and coldbox coremaking.
Case history: Arrow desired a sand reclamation system and made its choice based on the recommendations of other foundries. Its reclamation system produces sand that meets or surpasses the quality of new sand. Closing the loop on buying and dumping sand also has allowed Arrow to purchase better quality sand, improving its entire molding process.
PXC Compact Thermal Sand Reclamation Unit Vulcan Engineering Co.
One Vulcan Drive Helena Industrial Park
P.O. Box 307
Helena, Alabama 35080
Contact: Kevin Crawford.
System type: Thermal.
Dimensions: l7 ft x 9 ft 3 in. x l7 ft 10 in.
Capacity: 0.25-1 ton/hr.
Key attributes: Compact design allows smaller foundries with limited space constraints to have sand reclamation equipment. The dead bed area of the sand reclamation system uses the sand itself to protect the low thermal mass ceramic fiber insulation from the direct mechanical abrasion of the fluidized sand, eliminating the need for metal containment tanks within the furnace.
In operation: Sand enters the fluid bed heat exchanger and travels a circuitous path around the internal stainless steel tubes. Half of the furnace fluidization air is passed through these tubes and heated to approximately 930F (449C). It then is passed to the furnace via the pre-heat manifold. Hot sand then follows the circuitous path around the tubes with spiral wound fins. Cooling water passes through the tubes in a counter-flow path to cool the sand down to 18F (8C) above wet bulb temperature.
Foundry data: Integra Castings, Manitoba, Canada, is a gray and ductile iron foundry that uses nobake molds to produce manufacturing and agricultural castings from 100-500 lb.
Case history: Integra installed the thermal reclamation system in 1996, having previously used a mechanical system. Since installing the system, sand costs have decreased and the foundry is creating better quality castings--the reclaimed sand causes less veining and burning, making a better finish.
General Kinematics Corp.
777 Lake Zurich Rd.
Barrington, Illinois 60010
Contact: Bill Clark.
System type: Mechanical.
Footprint: 10 x 10 ft.
Capacity: 20-30 tons/hr.
Key attributes: The system is a 2-mass natural frequency unit designed for efficient heat removal with ambient air during lump reduction. After initial startup, energy only is required to overcome frictional losses as lumps and sand tumble in a fluid mass.
In operation: The unit's curved drum chamber works in tandem with vibratory motion to enhance tumbling action and attrition. A large curved screen area speeds up the reduction of nobake lumps to original grain size. Tramp metal is discharged through a pneumatically actuated side gate. Aspecially-designed air bag system tilts one end of the unit a few degrees to promote flow during the trash" unloading cycle.
Foundry data: U.S. filter Castalloy Div.'s steel foundry in Waukesha, Wisconsin uses nobake and shell molding and shell, coldbox and hotbox coremaking to produce manufacturing equipment.
Case history: Through an increase in casting capacity, Castalloy had outgrown its existing reclamation system. Sand lump reclamation had become a bottleneck. The foundry investigated several options, but many required extensive changes in process flow to accommodate an increase in the space required for an upgraded system. In the end, the foundry decided on a Vibra Mill Drum that could be installed in the existing area and only required slight modifications to conveyers. This system improved capacity from 5-6 tons! hr to 9-11 tons/hr and keeps pace with the furnace's melt capacity. Installation took three days.
GMD Thermo-Scrubber Thermal Sand Reclaimer
GMD Environmental Services
P.O. Box 11375
Fort Worth, Texas 76110
Contact: Jerry Reier.
System type: Thermal.
Footprint: 15 x 20 x 35 ft.
Capacity: 1 ton/hr.
Key attributes: The system uses close-coupled fluid beds that provide calcining and pre-cooling on a continuous basis by hot air scrubbing and gravity transfer without moving parts.
In operation: Sand is fed into a surge bin and then into the reclamation system. Calcining heat is added via the fossil fuel combustion system into the fluid bed at a temperature from 1350-1650F (732-899C). Supplemental fuel is fired in the firebox below the calcining chamber, eliminating coking and ensuring a consistent temperature in the calcining bed. The sand leaves the chamber by flowing over a weir, then travels through the transfer duct by gravity into the pre-cool chamber. There it is cooled with ambient air to a discharge temperature from 700-850F (371-454C).
Foundry data: Gregg Industries, Inc.,
El Monte, California, a green sand foundry, has been using the reclamation system since 1992.
Case history: Gregg Industries reclaims its excess sand and core butts to a condition equal to or better than the new sand. Return and excess sand is continually processed through the system. Clay-bonded sand from the molding operation and broken shell core butts can be processed together in any combination, producing usable sand. Much of this reclaimed sand is shell coated for use in its core room, while the rest is used as additions in the preparation of molding sand. The foundry no longer buys coated sand and purchases only a small amount of new sand to replace that lost through normal attrition. It estimates that without reclaiming excess sand, disposal costs would be $500,000 annually.
Fata Aluminum, Inc.
37654 Amrhein Rd.
Livonia, Michigan 48150
Contact: Brian Ginnard.
System type: Thermal regeneration.
Dimensions: Ranging from 16 ft 5 in. x 32 ft 10 in. x 37 ft 9 in. to 24 ft 8 in. x 49 ft 3 in. x41 ft.
Capacity: 3-12 tons/hr.
Key Attributes: This system can be used to reclaim both resin-bonded and green sand. The reclaimed sand can be reused throughout all types of molding and coremaking. The system runs automatically without the need for an operator.
In Operation: For chemically-bonded sand, a screw conveyor carries a metered amount of sand into a cylindrical calcination chamber with insulated walls and a stainless steel base plate. The base plate features fluidization nozzles placed together with gas feed pipes on the same axis. Air and gas are mixed together inside a combustion chamber. Sand flow from the combustion chamber to the pre-cooler is vale-controlled. The pre-cooler consists of two fluidizing beds connected by valves. A concurrent flow of air passes through the sand, cooling the sand to 572F (300C) while recovering 932F (500CD of heat energy. The sand then passes into the final cooler, which is composed of a fluid bed chamber equipped with a circulating water tube nest. After exiting from the final cooler, the sand passes over a vibratory screen that eliminates any remaining impurities. The process for green sand reclamation is similar.
Foundry data: Three Teksid Aluminum Foundries, two in Sylacauga, Alabama and one in Dickson, Tennessee use the Hot-Rec systems.
Case history: The Sylacauga plants each have a 12 tons/hr system that processes silica sand used in lost foam casting. These systems were ramped up in the last few months. The Dickson plant uses a 6 tons/ hr system for reclaiming coldbox cores used in semi-permanent mold casting.
RSR 5-1 Rotary Sand Reclaimer
Roberts Sinto Corp.
3001 West Main Street
P.O. Box 40760
Lansing, Michigan 48901
Contact: Roger Hayes.
System type: Rotary mechanical.
Footprint: 4 ft 6 in. x 9 ft.
Capacity: 3.3 tons/hr.
Key attributes: The reclaimer has low capital and operating costs but high throughput efficiency. One hundred percent of the reclaimed sand from the system is able to be reused in nobake molding. During operation, the system forces sand grains to scrub against each other, increasing reclamation efficiency.
In operation: The system receives shakeout sand into a receiver hopper. The sand then passes at a rated throughput into the rotary reclaimer cell. Fines are removed in a fluid bed classifier before the sand is sent to a surge silo. A transporter delivers reclaimed sand to a day hopper for use in molding and coremaking.
Foundry data: Schlumberger Industries, a phenolic urethane nobake shop in Tallassee, Alabama.
Case history: Schlumberger was looking for a reclamation system to reduce the sand disposal costs for its copper-base casting facility. The foundry wanted to reclaim the largest percentage of its 85 GFN silica sand possible, so efficiency of the reclamation system was critical. The foundry purchased an RSR 5-1 Rotary Reclamation System. The system included bucket elevators, the reclamation equipment and touch screen controls, surge storage, and a pneumatic transporter to bring reclaimed sand to the core room hoppers. "Before the reclaimer, we were hauling our waste sand out behind the plant," said Dave Patton, foundry manager. "Using the reclamation system, we are retaining 100% of our recycled sand. We are working 10-hr shifts, four days a week and are recycling more than 12 tons of sand/day." During the first two months of operation, the 10-hr for the reclaimed sand remained below 1% with a system throughput at 90% efficiency.
Model 4 Cell Pro-Claim
Simpson Technologies Corp.
751 Shoreline Drive
Aurora, Illinois 60504
Contact: Dave Silsby.
System type: Pneumatic reclaimer.
Dimensions: 21 ft 11.375 in. x 10 ft 11.375 in. x 13 ft 5.25 in.
Capacity: 8-10 tons/hr.
Key attributes: The system uses air as the motivating force and the sand grains as the abrasive body to scrub the sand clean.
In operation: The sand is propelled by air through an inside tube and scrubbed against sand trapped under a target. The sandlair mixture is established in the sand inlet mixing chamber. Agglomerates are disintegrated and the impringement of grains against each other scrubs off binder coatings. The sand curtain is exposed to exhaust air drawn through rectangular openings in an exhaust shroud that surrounds the target. This exhaust air removes the fines as they are created. The sand enters the final dedusting chute to pass through the vibratory classification screen. The reclaimed sand and the refuse are discharged separately.
Foundry data: A green sand foundry casts steel railroad components with sodium silicate cores. The foundry has a production rate of 22 tons of castings/shift and is using sand at a rate of 15 tons/hr.
Case history: This steel foundry was adding 25 tons/day of facing sand to its sand system and removing an equal amount to keep the sand system in balance. The sand removal from the system meant that valuable clay also was removed and sent to disposal. The foundry installed a pneumatic reclamation system with a feed hopper, cyclone and dust collection to improve the disposal situation. The reclaimer has a capacity to process 32,000 tons/year of sand. The reclamation system produces a yield of 85%, reducing disposal to only 15%.
The foundry realized a payback on the reclamation equipment in six months. Factoring in the sand and clay usage reductions, cost of operation, maintenance and other costs associated with the reclamation system, the foundry is saving more than $1800/day through reclamation.
Sand Lion Deep Fluidized Bed
Consolidated Engineering Co.
1971 McCollum Pkwy NW
Kennesaw, Georgia 30144
Contact: Jim Garrett.
System type: Fluidized bed thermal reclaimer.
Dimensions: 200 and 265 cu ft work capacities (depending on system).
Capacity: Starting at 2 tons/hr.
Key attributes: This reclaimer combines several foundry processes into one and has been applied most often to aluminum castings (although ferrous systems are available). In addition to thermally reclaiming sand, the system decores castings without knockout or shakeout. The system also can be equipped with quenching equipment for heat treatment.
In operation: The process begins as the castings with molds and/or cores intact are immersed in a heated bed of fluidized sand. The heat and oxygen present in the bed de-bond the molds and cores (which can be made with any thermally reclaimable binders). The sand is thermally reclaimed in the bed and cleaned sand overflows from a discharge spout.
Thermpak Reclamation System Castec, Inc.
1462 Delberts Drive
Monongahela, Pennsylvania 15063
Contact: Ron Parker. System type: Thermal.
Dimensions: 20 x 12 x 10 ft.
Capacity: 18 tons/day.
Key attributes: The post reclaimer increases throughput capacity and greatly improves operating efficiency. The system doesn't have moving parts in heat zones or use castable refractory.
In operation: The heat exchanger preheats the fluidizing air by utilizing the heat in the exhaust from the calciner. The fluidizing air then acts on the sand, which enters the post reclaimer. The sand cooler receives reclaimed sand from the post reclaimer and cools it to within 5 degrees of ambient air temperature.
Foundry data: Flotech, Inc., a nobake foundry in Jacksonville, Florida, installed a system in 1998.
Case history: Flotech purchased the system for its overall compactness and cost/results ratio. By installing the sand reclamation system, Flotech reduced overall sand purchases by 75%, resulting in a savings of $50,000/yr.
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|Date:||Aug 1, 2001|
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