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US 12,350,734 B2Granted
Recovering sand, bentonite and organics from foundry sand waste
AssigneeImerys USA, Inc.
InventorRobert C. Steele
Life of this patent
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Abstract
Both a hydraulic (wet) separation process and a dry separation process are used in combination to recover sand, bentonite clay and organics from foundry waste created during operation of a green sand foundry. These recovered ingredients are then recycled for reuse in making additional green sand molds.
Claims19
A process for recovering sand, bentonite clay and organic compounds from foundry waste produced by a green sand foundry, the process comprising:
- subjecting a first portion of foundry waste to hydraulic separation thereby producing an aqueous fraction rich in bentonite and organic compounds and an underflow fraction rich in coarse sand,
- subjecting a second portion of foundry waste to dry separation thereby producing a heavy fraction containing coarse sand and a light fraction containing bentonite and organic compounds, and
- using at least a portion of the bentonite and organic compounds from the aqueous fraction and the light fraction as a raw material for making green sand molds.
A method of forming a molding sand additive, comprising the steps of:
- subjecting a first portion of foundry waste to hydraulic separation thereby producing an aqueous effluent stream rich in bentonite and organic compounds, and an underflow stream rich in coarse sand,
- subjecting a second portion of foundry waste to dry separation thereby producing a heavy fraction containing coarse sand, and a light fraction containing bentonite and organic compounds, and
- combining the bentonite and organic compounds in both the aqueous effluent stream and the light fraction.
Dependencies are inferred from the claim text.