Used sand reclamation in foundries
FSP GmbH, founded in May this year, has commissioned a pilot-scale reclamation plant for water-glass bonded sands at its company headquarters in Stuttgart. Foundries can use this plant to perform sand reclamation tests. The plant is based on a wet reclamation process patented by DEANTEC. This process is highly energy-efficient and close to carbon-neutral. In addition to selling reclamation equipment, FSP also provides contract reclamation services to help foundries cut energy and personnel costs.
Foundries spend a great effort and considerable financial means on reclaiming foundry sands and core sands containing organic- or inorganic binder systems. Especially against the backdrop of the dramatic rise in energy prices, energy efficiency of reclamation processes has been moving increasingly into the focus. The patented process used by FSP reduces the energy required to dry the sand by about 60 percent and what“s more, it is carbon-neutral. With this process, foundries can substitute some 95 percent of their new sand requirements, reducing the costs of used sand dumping at the same time. The reclaimed product has the same quality as new sand. As an alternative option, FSP also supplies a basic-grade product that can be flexibly blended with new sand to achieve the sand quality specified by the customer.
FSP is the first manufacturer of reclamation equipment in the market to provide contract reclamation services in addition to supplying the equipment. Under its reclamation service contracts, the company processes used sand of most different origins in its own reclamation facilities. These facilities are usually located near the foundries or may even be set up on the foundries“ premises. In either case, FSP GmbH is the operator of the reclamation plant.
This November saw the commissioning of a pilot-scale reclamation plant at the FSP headquarters in Stuttgart. Customers can use this plant to test the process with their own sands. The plant is designed for throughput rates of up to one ton per hour.
Stefan Zimmermann, Managing Director of FSP GmbH, emphasizes the resource-saving aspect of the process: „I believe that we will all have to adjust to higher energy prices in the long term. And we should bear in mind that new sand is not an endless resource. Therefore, used sand dumping is definitely not a future-viable way of dealing with this valuable resource. With our process, foundries can save a lot of energy and make their sand reclamation operations almost carbon-neutral because FSP generates the necessary energy itself by cogeneration backed with photovoltaics.“
The technology in detail
The process removes contaminants from used sands with an effectiveness of 98 percent. Therefore, the reclaimed sand has almost the same strength and flowability as new sand.
The FSP process, protected by a worldwide patent, is a highly efficient, energy-saving wet-reclamation process for inorganic-bonded core sands. With this process, all common water-glass bonded foundry sands and special sands from 3D printing can be completely reclaimed.
In the patented drying system, the sand is not dried with air but by turning the water it contains from liquid into gas. For this, energy recuperated from the condensation process is used to the greatest possible extent. By recuperating more than 60 percent of the condensation energy, the evaporation energy is kept within the system.
In addition to this, dust particles are removed from the sand in a patented fluid bed cooling separator.
The process water is treated and maintained within a closed circuit. One ton of sand generates just 12 liters of waste water. Only this amount of fresh water has to be added to the process. Also during the distillation process, condensation energy is recovered. 95 percent of the energy required for the evaporation process is energy recuperated from condensation. The distillate is entirely demineralized. Thus, it is even better suited for the sand washing process than fresh water.
The patented FSP process can also be used as a wet conditioning process for bulk materials of different kinds and origins.
Next, FSP is adding a thermal treatment stage to the pilot plant at its Stuttgart facilities. Also this new process equipment will set new standards in terms of energy efficiency. While the so far common thermal and combined mechanical-thermal reclamation processes consume between 22 and 30 m³ of gas per ton of sand reclaimed, the innovative FSP technology brings the per-ton gas consumption down to 13 to 16 m³. In this way, foundries with hourly processing rates of about six tons can achieve yearly gas savings worth 240,000 euros.
Compared to mechanical methods, thermal reclamation is gentler to the material. The binders are removed without damaging the sand grains and the process is practically dust-free. Hence, no additional dumping costs arise for the foundries. The fine-grain fraction of the reclaimed sand is less than 0.3 percent.
FSP GmbH Foundry Sand Processing, founded in Stuttgart/Germany in May 2022, develops and supplies systems and solutions for bulk material reclamation and processing. The company builds on several decades of experience in raw material recycling, and thermal and wet reclamation of foundry sands.
The founding partners are the German companies Heinrich Feess GmbH & Co. KG, based in Kirchheim/Teck, and DEANTEC GmbH, based in Kirchhundem/Germany. While Feess, winner of the German Environmental Award in 2016, provides in-depth know-how in mineral waste recycling to the new company, DEANTEC contributes its unique, patented wet-reclamation and drying technology, a process that operates exclusively on renewable energy.
The merger into FSP GmbH has created a one-stop supplier of virtually carbon-neutral systems for the entire sand reclamation process chain. With the reclaimed sand, foundries can substitute up to 95 percent of their new sand requirements, making an important contribution to a resource-saving, sustainable production.
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