Sand reclamation equipment: users answer the questions.

For the benefit of those still 'on the fence' about sand reclamation equipment, some experienced foundrymen tell their stories.

"If it's not something the customer sees in the product, or something that increases volume, it's not a high priority." It's an understandable attitude, and probably the reason many foundries still are not reclaiming their sand. Despite the fact that the technologies and economics of sand reclamation are now pretty well proven, foundrymen are reluctant to divert precious capital in that direction while quality and productivity improvements beckons.

Yet from the foundries that are reclaiming come success story after success story. Not only have disposal and new sand costs been slashed, but many are seeing added savings in binder use, while sand quality has improved.

To be sure, there are hard questions that must be asked before reaching a decision about sand reclamation, and your situation will obviously dictate your needs. Small foundries may not use enough sand to justify the cost. Some firms are in the enviable position of supplying their sand for external beneficial reuse - something all foundries should seriously investigate. Others are reluctant to commit to an investment that may end up snagged in the ever-changing net of environmental regulations.

If, however, you've concluded that in-house sand reclamation is the way to go, it is obviously necessary to gather as much data as possible, and to follow a structured procurement procedure. As with any capital investment, a definite objective is the crucial starting place. What do you want to do with reclaimed sand; use it in the coreroom, or back on the molding line? What volume of sand will you be reclaiming on a daily or weekly basis? Do you want to cut new sand costs? Disposal costs? Reduce regulatory concerns? All three?

Your sand system is unique when daily volume, molding sand, core sand and binder, and metal poured are all added up. Since reclamation methods differ in what they accomplish, it is important to determine what you need.

But understanding the technology just scrapes the surface. Additional equipment, such as coolers, lifts and conveyors, leave price and operation question marks. As does the effect of reclamation on your sand quality and process flow. Sand reclamation is an entire "can of worms."

To help foundrymen who are still unsure about sand reclamation, these pages profile some of the various systems on the market. Users of these systems were contacted to hear of their experiences and find out how they look back at opening the can of worms.

Southern Aluminum Bay Minette, Alabama 

LC-5 Rotary Lump Crusher/Reclaimer, Didion Mfg.

Souther Aluminum's reclamation experience is atypical, but nonetheless impressive. The high-production automotive foundry has always been fortunate enough to have an external destination for its spent green sand and chemically-bonded core butts. At first, the city was using it for cover on a brush landfill; the foundry paid $3 per ton to have it trucked to the site.

Recently, a local asphalt company became interested in reusing the foundry's sand in its product. According to Plant Engineer Dick Lingenfelter, "We looked at internal reclamation, but when you don't pay anything to get rid of it, it doesn't make sense." All that's required by the asphalt company is that the lumps are crushed and tramp aluminum over 1/8 in. in size is removed.

After careful analysis of the various reclamation systems on the market, officials chose the didion LC-5, in which sand lumps and tramp metal are fed into one end of the rotating drum. Rifling urges the material into the attrition/scrubbing chamber, in which wear-resistant liners reduce the lumps and scrub binder off the grains. The granular sand enters the screening and classifying section, while binder and fines are removed by the dust collector. Clean tramp metal exits the other end of the drum, and counterflow heat thoroughly dries the sand during the attrition process.

Installed this past January, the new unit's first task was reclaiming three months worth of spent sand that had collected outside on the property. Within two weeks, Southern Aluminum had recovered 187,045 lb of aluminum from the sand - $149,636 worth. "We had payback on the reclaimer in less than a week," Lingenfelter said.

"We thought we'd have to pay to get the aluminum out of our sand," he said. "We're actually making money because we're getting a lot more aluminum than we thought - about 6000 lb per day. This is a great success story. The reclaimer is the biggest profit center in the foundry."

Gregg Industries El Monte, California 

GMD Environmental Systems Thermo-Scrubber TS

"We began reclaiming our sand because of the cost of disposal in California," said Gregg Industries' Butch Griffiths. The iron and steel foundry has had its Thermo-Scrubber in operation for four years. The 1 ton per hr unit is reclaiming 100% of the foundry's shell core butts and 100% of its spill green sand. Most of that sand goes back to the coreroom for recoating in the shell process; the rest is used for green sand additions.

The GMD unit is purported to be the only thermal sand reclaimer that can successfully reclaim green sand for reuse in a green sand system. At Gregg Industries, at any given moment it may be processing green sand, shell sand or any mixture of the two. The unit continually processes sand, running unattended 24 hr a day. The sand is heated in a calcining fluid bed to 1350-1650F (732-898C), before being cooled and penumatically scrubbed to remove dead clay and, binder and fines. The reclaimer also includes the Thermo-Minder system, which has archiving capabilities, and displays and documents profiles and trend at all critical process points. It also is linked via phone line to GMD's offices in Texas, where it can be remotely monitored and supported.

Griffiths said the foundry uses SPC for sand control, and "our QC people haven't reported any change in sand quality since before we installed the reclaimer - casting surface quality is the same." From a financial standpoint, the unit is performing at expectation, saving Gregg Industries "probably $500,000 per year," Griffiths said. "We've cut our disposal costs in half. Our estimated return on investment was 3.5 years, and we hit that easily. Also, because we can now coat our own sand, we also cut our shell sand costs by about half.

"In addition, we have excess capacity on the reclaimer, so we take sand from other foundries, reclaim it, coat it and sell it back to them."

Taylor & Fenn Co. Windsor, Connecticut 

Pro-Claim, Simpson Technologies

Because the foundry was landfilling 300-320 tons per week from its nobake molding line, Taylor & Fenn officials were concerned about disposal fees and environmental regulations. However, "Sand quality was the biggest factor," said Vice President Ernie Roberts about the foundry's installation last October of a two-cell Pro-Claim attrition reclaimer. "We'd been using another mechanical reclaimer for years, but it didn't get our sand clean enough. We were adding up to 20% new sand just to keep the combustibles in our furan-bonded sand down at 3.5%."

The ferrous foundry began the process of searching for a sand reclaimer that could alleviate the problem. "We investigated and ran numbers on various mechanical and thermal reclaimers - my first reaction was to go thermal," Roberts recalled. "We visited a lot of foundries that had thermal reclaimers to see what they were doing. But the cost and space requirements didn't suit us. Therefore, we decided on mechanical and then narrowed it down to Simpson."

The foundry's new reclaimer processes 75-80 tons/day in a 16 hr day, and has the capacity for 24 hr operation, if needed. "Installation was no big deal," Roberts said. "We did a lot of upfront engineering to make it as easy as possible, and the reclaimer is small and fit right in. Of course it takes a dust collector and other ancillary equipment, and debugging and balancing the flow took a couple of weeks, but the Proclaim started doing exactly what we wanted it to do the day we turned it on, which was lower the LOI." The shop's modified sand system now features: shakeout, overhead silo, Pro-Claim, cooler/classifier, silo, and molding.

"The maintenance crew had to be thoroughly trained on the unit - the key to any installation is to familiarize your maintenance people with the equipment. But nobody was hired to run the machine, and it doesn't make any personnel demands."

Within the Pro-Claim, the sand is propelled by air through a blast tube at a conical target, where it is scrubbed against sand already trapped under the target (this grain-to-grain action greatly reduces wear on the machine parts). The process is then repeated in the second cell, while a dust collector removes binder and fines. A high percentage of the reclaimed sand goes right to the coreroom.

Roberts said the reclaimer is fully meeting expectations: "Our sand quality is the best it's ever been in terms of cleanliness. Our LOI is now down to 1.25% when the sand leaves the reclaimer. The 20% virgin sand we were adding is down to 5-8%, and that's just to replace sand lost from the total system.

"The tangibles - new sand savings and disposal cost savings - are there," Roberts observed, "and landfilled nobake sand is down about 65%. The intangibles are harder to quantify. They come with improved casting quality. Our scrap rate is the same, but we're doing less cleaning room work, we're seeing less burnt sand, and I think the castings look better."

Castalloy Corp. Waukesha, Wisconsin 

Thermfire 3000, Gudgeon Brothers., Ltd.

Castalloy Corp., a steel foundry producing castings for heat treat and other industries, uses nobake- and coldbox-bonded silica for its mold and core-making. In the early 1990s, with the cost of landfilling skyrocketing to near $40 per ton of sand, the foundry was faced with a dilemma. Plant Engineer Glenn Furst explains: "We run a traditional system, in which we add new sand to keep our combustibles down to a minimum. We were adding up to 30-40% new sand a day to keep it that way, and the replaced sand had to go to landfill. So we saw sand reclamation as a way to control landfill costs."

For the process of shopping for a sand reclamation system, the foundry formed a committee to study the problem and determine the method and equipment that would make sense for Castalloy's needs. Deciding thermal reclamation was the way to achieve the LOI reduction, "We looked at 4 or 5 gas fired systems, having ruled electric out early as too costly," Furst said. "The committee then came up with a list of four or five questions we wanted to ask the supplier: could they guarantee an LOI of nearly zero; could they meet current and potential emissions regulations - preferably, this would be documented; what would be maintenance cost and ease; and what would be the operational costs."

Getting the answers they wanted from Gudgeon Brothers, the committee investigated further. "Gudgeon had a prototype unit in their shop in which they ran our sand. We also talked to their two previous installations - and were satisfied with their experiences," Furst said.

Up and running since October 1993, Castalloy's Thermfire is in operation 24 hr per day, reclaiming 36 tons in that span. The unit consists of a calcining fluid bed, in which the sand is indirectly heated to a temperature at which the LOIs and the binder are completely combusted, stacked above a cooling fluid bed. The air used to cool the sand in the bottom bed picks up heat from the sand and is fed back into the calcining chamber to help heat the combustion air. This saves energy needed to completely combust the residual elements in the sand.

As an economic investment, Furst said Castalloy's venture into sand reclamation was very successful: "I'd put our return on investment at about 1.5 years. It costs us $7 per ton to reclaim the sand, including maintenance, energy, etc. - as compared to the $20 per ton for new sand."

Sand quality has improved, as well. "We have a molding system that allows us to use a facing sand, which is 100% reclaimed sand," Furst said. "That sand has an LOI of about .01%. We've also cut our use of additives like iron oxide - in some cases eliminating them altogether."

Covert Iron Works Huntington Park, California 

R-1 Sand Reclamation System, Palmer Manufacturing, Inc.

"We've had a Palmer R-1 for about two years," said Roy Covert, president of Covert Iron Works, an iron foundry supplying castings to the construction, agriculture, aftermarket automotive and capital machinery industries. "We bought it because we were expanding our furan nobake operation and the cost of sand disposal kept getting higher.

"We looked at a lot of competing systems, but I considered the Palmer equipment to produce the best for the amount of capital outlay," Covert said of the selection process. "There was very little ancillary equipment required - it has its own baghouse - it was just plug it in and let it go."

In operation, the R-1 has a capacity of up to 3000 lb per hr. It consists of a heavy-duty LB-1 top-loading attrition mill with a 2-hp, 1200 RPM vibrator that is bottom-mounted for maximum agitation of the sand mass. Its dual screen scrubber and reduction system allows only granular sand to exit the mill. It has a fluidized bed classifier powered by a regenerative-type blower. Controls offer automatic or semi-automatic operation.

Covert said his foundry uses the system to reclaim its furan nobake sand. The reclaimed sand is mixed with 20% new sand and sent right back to the molding line. "Our disposal fees were cut by 60%," Covert said, explaining that the shop still landfills its slag and the sand from its green sand line. In addition, the foundry's new sand purchases were cut by one half.

Besides the system's low maintenance and operating cost, Covert said, "It allowed us to expand our nobake operations, which has gotten us some new business. This was a great investment for us. It was even bought when business wasn't good, and it still provided a payback in 12 months."

Hazleton Pumps Hazleton, Pennsylvania 

Calcifire, Dependable Foundry Equipment Co.

Charles Harris, Manufacturing Manager of Hazleton Pumps, has some considerable experience with thermal sand reclamation. Warman Industries, Hazleton's parent company, also owns Warman International's foundry in Sidney, Australia, where Harris worked before transferring to the U.S.

"We bought a 2.5 ton per hr Calcifire thermal reclaimer in Australia more than two years ago, along with an attrition system," Harris said. "There were environmental concerns - we were in the middle of Sidney, so it was an environmental hotspot. Not only that, but it was a major inconvenience in that urban area. We had about 200 sand trucks a year in and out of the foundry. Disposal was difficult.

"At the time we bought the equipment, we felt nobody else was providing an affordable combination of a thermal and mechanical unit in one system," Harris said. The attrition system breaks lumps and prescrubs the sand. The gas-powered sand reclaimer directly burns binder from the sand in a fluid bed, while a heat recuperation system captures potentially lost heat from outgoing exhaust and cycles it back through the bed. Emissions are controlled with an afterburner arrangement.

"We had a return on investment in fewer than 12 months. When you consider that we were using 30,000 tons of sand per year, it definitely paid," Harris said. In terms of new sand costs, Harris shared an anecdote: "The reclaimer had been running for about two years when we had a small problem and had to shut it down briefly. We ran into the embarrassing situation of having forgotten what a problem it was to buy and dispose of new sand. We no longer had the procedures in place."

The experience with the equipment in Australia had been such that Hazleton recently installed a 0.5 ton per hr unit to reclaim a furan binder system for use in the coreroom. "The system is still new, so we haven't judged the full impact of it yet," Harris admits. "But I'm convinced sand reclamation is the way to go. At the outset, it appears expensive, but the payoff is there eventually."

Empire Steel Castings Reading, Pennsylvania 

Thermpak, Castec, Inc.

In 1991, Empire Steel Castings bought and installed a Thermpak thermal sand reclaimer, a comprehensive system that includes a calciner, sand cooler, dust collector, compressed air source and ancillary equipment.

The batch-type reclaimer features a deep bed calcining vessel with a peripherally-fired, indirect heating arrangement that ensures all sand grains are exposed to equal combustion air, and a cooler that lowers sand temperature to 90F (32C), while classifying through controlled fines movement. The unit destroys all organic matter as the exhaust gases pass through the afterburner to a heat exchange that significantly cuts dust collection requirements.

Three weeks after the prepiped and prewired unit was delivered, it was running unattended around the clock, seven days a week. According to Empire president Ed Crowley, the foundry reclaims 5000 tons of its chemically bonded sand per year, for a total of 20,000 tons since installation.

"The economics of the system are beyond expectation," he said. "Our annual savings exceed $225,000." The local power company continuously monitors the system, and the total electric power for the entire setup averages 125 kWh. Also, without moving parts in the heat zone, maintenance costs are low - less than $6000 per year at Empire.

Four years of successful reclamation have led Crowley to say: "Our decision to go thermal has proven to be a wise business and economic move, and more importantly, we've eliminated many present and future environmental problems."

Carondelet Foundry Co. Pevely, Missouri 

Simplicity/Richards Thermal Reclaimer, Simplicity Engineering Co.

According to Plant Engineer Gary Kolaks, Carondelet Foundry began looking into sand reclamation in 1991 because of a number of factors. The steel jobbing shop was using an average of 150 tons of sand per day; with spent sand transportation charges of $350 per 12 cu yds and new sand charges of $575 per 26-ton load. Besides those costs, the foundry wanted to end the uncertainty of being at the mercy of occasional trucking strikes and bad weather. "The biggest reason was independence," Kolaks said.

"We looked for a couple of years, eventually choosing the Simplicity gas-fired unit," Kolaks said. "The final decision was based on cost, and the fact that the unit had a low thermal mass blanket for insulation."

Easily installed in a new foundry facility that had been designed with sand reclamation in mind, the thermal reclaimer has been in 24-hr operation since January 1994. It features a multi-zone fluidized bed that improves combustion efficiency and reduces emissions. Each zone is independently controlled to provide accurate temperature and required retention time for the sand. The fully automatic, PLC-controlled system employs a heat exchanger for maximum fuel efficiency - a characteristic enhanced by Carondelet's addition of auxiliary heat recovery equipment from GMD. Besides the thermal unit, the foundry also purchased a Simplicity mechanical reclaimer, a dust collector, magnetic separator and belt conveyor system.

The reclaimer is processing 125 tons of sand per day, while the mechanical unit reclaims another 25 tons. All of that sand would otherwise be heading for the landfill. "We're reclaiming 99% silica (1% zircon) with phenolic urethane nobake and phenolic urethane Isocure, with a 1% binder level. That binder level is important," Kolaks pointed out, "because before we bought the system, the level was 1.2%." Kolaks said the thermally reclaimed sand is better than new.

The foundry saw a return on its investment in under a year, and Kolaks estimated the reclamation system was saving the Carondelet more than $1 million per year. "It's saving us a lot of money, giving us better sand and our castings look better," he said. Best of all, besides a 5% new sand addition, "We're 95% independent."

Durametal Corp. Muncie, Pennsylvania

Vibra-Mill, General Kinematics Corp.

As part of an overall sand reclamation package, Durametal bought a Vibra-Mill more than three years ago to replace another lump crusher that had frequent maintenance problems. The 120-employee iron and steel foundry, which mainly serves the pulp and paper industry, uses the setup to reclaim its nobake molding sand.

The Vibra-Mill has an open tub design mounted on low-stress steel coil isolation springs that minimize floor vibration. Dual, self-contained motorized counterweight drives provide the vibrating force for the unit's operation.

The sequence of Durametal's sand reclamation system is: a vibratory shakeout feeds sand directly to the Vibra-Mill. Inside the unit, lumps are reduced to [less than] 20 mesh with original grain size distribution and a corresponding reduction in LOI. Tramp metal and fines are removed and the sand passes through a final screen to ensure cleanliness. From the Vibra-Mill, the sand goes via bucket elevator to the foundry's mechanical and thermal reclaimers.

Barry Hodge, Durametal's manager of product engineering, said the Vibra-Mill "has held up very well" in its nearly four years of service. Of the firm's experience in sand reclamation, Hodge said, "There's no other way to operate these days. We reclaim 100% of our nobake sand, adding 5-10% new sand. We dispose of 1600 tons of nobake per year, but that figure might have been 10 times as high before reclamation."

RELATED ARTICLE:

Following are some of the crucial questions foundrymen ask of suppliers and themselves when trying to select sand reclamation equipment.

1. Does the equipment supplier have a test facility where it can reclaim samples of our sand?

2. What will be the approximate energy costs for operation?

3. What alterations will have to be made to the current sand system apparatus? Ancillary equipment?

4. Will installation require foundry construction? Are there pits involved? Will it impact production?

5. What can we expect from the equipment supplier in terms of debugging, training, total equipment supplied?

6. What are the personnel requirements of running this equipment. Maintenance time and costs?

7. Will this equipment meet current and potential environmental regulations?

8. How will the quality of reclaimed sand compare to our current system sand?

9. When can we expect a return on the investment?

10. Will there be any side benefits, such as better casting surface finish?