# US 2001/0041226 A1 · Method and arrangement for regenerating a contaminated metal bath > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2001/0041226 A1 - Document ID: US20010041226A1 - Status: Published application - Kind: A1 - Application number: 09/843,092 - Filed: 2001-04-26 - Published: 2001-11-15 - Earliest claimed: 2000-04-26 - Assignees: Stolberger Metallwerke GmbH & Co. KG - Inventors: Klaus Elbern; Robert Leffers; Albert Rumbach - Web page: https://patentgrep.com/patent/US20010041226A1 ## CPC - C23C 2/00: Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor - C23C 2/325: {Processes or devices for cleaning the bath} - Y02P 10/20: Recycling - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A method and a system for regenerating a metal bath contaminated by mixed crystals, particularly a tin bath (17) in a hot-dip coating process. A partial stream of the tin bath (17) is removed from the coating tank (15) and is first of all heated above its liquidus temperature in a heating unit (24). Subsequently, the tin bath is conducted over a cooling unit (27) and, while flowing through a filter (29), is cleaned of mixed crystals coming down as a result of the cooling. The filter 29 is a ceramic foam filter made of silicon carbide. Subsequently, the regenerated tin bath (17a) is heated in a melting tank to process temperature, and returned from there to the coating tank (15). ## Claims ### Claim 1 A method for regenerating a metal bath contaminated by mixed crystals, comprising the steps of: heating the metal bath above its liquidus temperature, and removing mixed crystals coming down during cooling, wherein the metal bath, after being heated to at least its liquidus temperature, is conducted over a cooling unit (8, 27) and, during flow-through, is guided through at least one filter (12, 29). ### Claim 2 (depends on 1) The method according to claim 1, wherein a ceramic filter (12, 29) is used. ### Claim 3 (depends on 1) The method according to claim 1, wherein a foam filter based on silicon carbide or an aluminum oxide filter is used. ### Claim 4 (depends on 1) The method according to claim 1, wherein the metal bath is taken from a coating tank (15) and is heated, cooled and then filtered on its way to a melting tank (32), whereupon, in the melting tank (32), temperature of the regenerated metal bath is increased, and the metal bath is returned from the melting tank (32) to the coating tank (15). ### Claim 5 (depends on 2) The method according to claim 2, wherein the metal bath is taken from a coating tank (15) and is heated, cooled and then filtered on its way to a melting tank (32), whereupon, in the melting tank (32), temperature of the regenerated metal bath is increased, and the metal bath is returned from the melting tank (32) to the coating tank (15). ### Claim 6 (depends on 1) The method according to claim 1, wherein the metal bath is a tin bath containing more than 50% tin, wherein the tin bath, on the way to the filter (12, 29) is first heated to a temperature TH, between 230° C. and 350° C., and is subsequently cooled to a temperature TK, between 210° C. and 250° C. ### Claim 7 (depends on 2) The method according to claim 2, wherein the metal bath is a tin bath containing more than 50% tin, wherein the tin bath, on the way to the filter (12, 29) is first heated to a temperature TH, between 230° C. and 350° C., and is subsequently cooled to a temperature TK, between 210° C. and 250° C. ### Claim 8 (depends on 4) The method according to claim 4, wherein the metal bath is a tin bath containing more than 50% tin, wherein the tin bath, on the way to the filter (12, 29) is first heated to a temperature TH, between 230° C. and 350°0 C., and is subsequently cooled to a temperature TK, between 210° C. and 250° C. ### Claim 9 (depends on 1) An arrangement for carrying out the method according to claim 1, comprising a pump (6, 23) for conveying metal bath from a tank (2, 15) to the cooling unit (8, 27) and to the filter (12, 29) downstream from it. ### Claim 10 (depends on 9) The arrangement according to claim 9, further comprising a heating unit (24) placed upstream from the cooling unit (8, 27). ### Claim 11 (depends on 10) The arrangement according to claim 10, wherein the heating unit (24) is heated with waste gas. ### Claim 12 (depends on 9) The arrangement according to claim 9, wherein the filter (12, 29) is a ceramic foam filter made of silicon carbide or aluminum oxide. ### Claim 13 (depends on 9) The arrangement according to claim 9, wherein the cooling unit (8) is formed by a downhill grade (10). ### Claim 14 (depends on 13) The arrangement according to claim 13, wherein the downhill grade (10) can have its inclination changed.