Higher environmental regulations, rising energy prices and increasing scarcity of new sand are leading many foundries to reconsider the regeneration of waste sand. As a manufacturer of sand processing plants, FSP Foundry Sand Processing offers an operator model as service, that enables foundries to regenerate used sand in a cost- and resource-saving manner. The special feature of FSP Foundry Sand Processing is the globally patented wet regeneration process for water glass-bound waste sand, that has been successfully used in the pilot plant at the Stuttgart site since 2022. In addition, a further pilot plant for mechanical-thermal regeneration has been in operation at the Stuttgart site since May 2024.
Expansion of the existing pilot plant for wet regeneration
The sustainability and great energy-saving potential of the wet regeneration plant is remarkable, as FSP Managing Director Stefan Zimmermann (Dipl. Oec.) emphasized at the company's first in-house exhibition. "Thanks to our patented drying process and integrated water treatment, 98% of the essential components can be recycled! Water is treated, distilled and fed back into the washing process. Only 12 liters of fresh water per ton of material need to be refreshed. The normally high energy consumption of conventional drum drying is compensated in our system by condensation recovery. This leads to a reduction in energy consumption of up to 60%. The current throughput time of the wet regeneration plant is 1 ton of sand per hour. After the expansion of the plant, it will be 3 tons of sand per hour. The expansion of the existing pilot plant for wet regeneration is planned for a well-known car manufacturer.
During regeneration, up to 100 percent of the sand can be returned to the cycle as reclaimed material
A major advantage of wet regeneration is that up to 100 percent of the sand can be returned to the foundry's material cycle as reclaim - thanks to the patented process. Comparably very good results are also achieved with mechanical-thermal regeneration. "We achieve a regeneration rate of 85% and an energy consumption of less than 10kW/h of material". "We are the first company in the world to offer a wet regeneration process for water glass-bonded used sand," Stefan Zimmermann stated when asked how FSP Foundry Sand Processing differs from other sand processing providers. "We are the only company in Europe that offers the regeneration of used sand as a service. This not only saves foundries the cost of purchasing new sand. This new operator model also significantly reduces their investment, energy and personnel costs. By outsourcing, foundries are also making an important contribution to implementing the circular economy!"
The service model is simple: FSP operates regeneration plants near foundry sites, collects the used sand from the foundries, regenerates it and returns the sand to its customers. The process technology used ensures that there is no mixing of the regenerates and that every customer receives the regenerate from its used sand.
"Not only is the sand reused again and again during casting, energy, water and air are also constantly circulated in the recycling process. And last but not least, the processing of the sand at FSP is largely CO2-neutral."
The opening of two to three more locations is planned
In the future, FSP Foundry Sand Processing plans to establish two or three further locations, each of which will supply other foundries within a radius of 200 to 300 km from the respective site. These will each have a capacity of around 180,000 to 200,000 tons of used sand per year. As future locations, Stefan Zimmermann takes the Ruhr region and the new German states into consideration. "The aim is to establish and expand our service model," Zimmermann explains.
Pilot plant for wet regeneration and mechanical-thermal regeneration
In addition to the pilot plant for wet regeneration, a further test plant for mechanical-thermal regeneration with a capacity of around 1 t/h has been available to customers since May 2024. FSP GmbH is also planning to install a mechanical-thermal plant with a throughput of 6 t/h, i.e. around 70,000 to 75,000 t/a, at its headquarters in Stuttgart over the course of this year. The plant will be ready for series production at the beginning of 2025 and will primarily supply foundries in the greater Stuttgart area and the rest of Baden-Württemberg. The cooperation partner in plant construction is Dürmeier GmbH from Vaihingen.
About the regeneration of inorganic- and organic-bound core sands
Washing is the gentlest method for regenerating inorganically bonded core sands, as there is no direct mechanical impact on the sand grain. This means that no additional dust is formed and all common water glass-bonded used sands and special sands from 3D printing can be fully processed. The process allows up to 98 percent of adhering residues to be washed away from the used sand. The process water required for the washing process is treated and kept in a closed cycle. The resulting waste is disposed of in a certified process. In the patented drying system, moisture is extracted from the sand in an energy-efficient manner through condensation.
FSP is also setting new standards with mechanical-thermal regeneration. The process can be used for both bentonite-bound green sand and organically bound core sand (cold box, hot box, shell sand, furan). Compared to conventional mechanical or purely thermal regeneration processes, the process technology reduces the dust content to a minimum.
The thermal-mechanical regeneration is characterized by the high efficiency of the three-stage system. After pre-treatment of the used sand, the sand is fed dry and free-flowing to the first - mechanical - stage, in which sand grain by sand grain and thus the binder is removed.
In the second stage, the sand is fed to the thermal stage. Gas and air mix in a sand bed, it fluidizes and the organic binder and fines are burned off. The effect of the quartz cracking loosens any remaining binder from the natural recesses of a grain of sand, or even blasts it off. In the third, also mechanical stage, the last residues are rubbed off the grain; it works in the same way as stage one.
Both test facilities will be available to foundries from May 2024. They can be used to test and analyze the regenerability of inorganically or organically bound sands, or even mixed sands. FSP offers interested customers a range of different tests - from a simple test series with up to 1 t of sand to a complete free-running process with determination of the best possible ratio of reclaimed and new sand in core production. At the end of the tests, customers receive the reclaim, dust and waste backpacked in big bags. This allows them to draw conclusions about the composition of the reclaim, for example the ratio of reclaim to fines and residual materials.
About FSP GmbH
Founded in Stuttgart in May 2022, FSP GmbH Foundry Sand Processing develops and sells systems and solutions for the regeneration and processing of bulk materials. The basis is decades of experience in the recycling of raw materials and the mechanical-thermal or wet regeneration of used foundry sands.
The founding partners are Heinrich Feess GmbH & Co. KG in Kirchheim/Teck and DEANTEC GmbH in Kirchhundem. Feess, which was awarded the German Federal Environmental Prize in 2016, contributes its expertise in the recycling of mineral waste, while DEANTEC contributes its experience with its unique, patented wet regeneration and drying process - a plant technology that uses only renewable energy in the processing of used sand.
FSP GmbH offers customers the complete, almost CO₂-neutral sand processing chain. The reclaimed material replaces up to 85% of new sand in the case of organic-bound sand and 95% in the case of inorganic-bound sand. FSP GmbH makes an important, measurable contribution to resource conservation and sustainable production.
