# US 5,350,438 A · Method and apparatus for removing plated metal from steel sheet scraps > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,350,438 A - Document ID: US5350438A - Status: Granted - Kind: A - Application number: 08/155,810 - Filed: 1993-11-23 - Granted: 1994-09-27 - Earliest claimed: 1991-05-23 - Assignees: Toyota Jidosha Kabushiki Kaisha; Toyokin Kabushiki Kaisha - Inventors: Yuji Okada; Shunichi Fujio; Kazuhiro Suzuki; Teruharu Shinoyama; Yasuo Takeuchi - Web page: https://patentgrep.com/patent/US5350438A ## CPC - C22B 21/0069: {from scrap, skimmings or any secondary source aluminium, e.g. recovery of alloy constituents (C22B21/0046, C22B21/0053 and C22B21/0092 take precedence)} - B03B 9/061: {the refuse being industrial} - B09B 3/40: involving thermal treatment, e.g. evaporation (processes using mineral binders involving a melting or softening step B09B3/29; involving radiation B09B3/50) - C22B 1/005: {Preliminary treatment of scrap (C22B1/02 - C22B1/26 take precedence)} - C22B 7/001: {Dry processes} - C22B 9/02: Refining by liquating, filtering, centrifuging, distilling, or supersonic wave action {including acoustic waves; (C22B9/003, C22B9/006, C22B9/05, C22B9/22 take precedence)} - C22B 19/04: Obtaining zinc by distilling - Y02P 10/20: Recycling - Y10S 266/901: Scrap metal preheating or melting - C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS - B03B: SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS - B09B: DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Metal plated steel sheet scraps are heated to a temperature in the range of about 200.degree. C.-500.degree. C. so that organic material adhered to the scraps is evaporated and removed. Then, the scraps from which organic material has been removed are heated to a temperature in the range of about 500.degree. C.-950.degree. C. so that the plated metal, for example zinc or aluminum, is evaporated. The evaporated metal flows to a retrieving device where the evaporated metal is condensed and retrieved. ## Claims ### Claim 1 A method for removing plated metal from steel sheet scraps comprising the steps of: preheating metal plated steel sheet scraps in a preheat chamber; heating the preheated scraps to a temperature in a range of about 200.degree. C.-500.degree. C. under reduced pressure in a pretreatment chamber to evaporate organic material adhered to the scraps and contained in the scraps; capturing the evaporated organic material; conveying the scraps through an intermediate chamber into a treatment chamber; heating the scraps to a temperature in a range of about 500.degree. C.-950.degree. C. and reducing a pressure in the treatment chamber to evaporate plated metal from the scraps; retrieving the evaporated metal; and cooling the scraps with gas in a cooling chamber. ### Claim 2 (depends on 1) A method according to claim 1, wherein the plated metal is zinc. ### Claim 3 (depends on 1) A method according to claim 1, wherein the plated metal is aluminum. ### Claim 4 (depends on 1) A method according to claim 1, wherein said cooling gas used for cooling the scraps is circulated from the cooling chamber to the preheat chamber so that thermal energy retrieved from heated scraps is used for preheating further scraps. ### Claim 5 (depends on 1) A method according to claim 1, wherein a reduced pressure in the pretreatment chamber is generated by a pressure reducing pump connected to the pretreatment chamber via a passage and wherein the evaporated organic material is captured by a filter disposed in the passage connecting the pretreatment chamber to the pressure reducing pump. ### Claim 6 (depends on 1) A method according to claim 1, wherein a reduced pressure in the treatment chamber is generated by a pressure reducing pump connected to the treatment chamber via a passage and wherein the evaporated metal is retrieved by a retrieving device disposed in the passage connecting the treatment chamber to the pressure reducing pump. ### Claim 7 (depends on 6) A method according to claim 6, wherein the evaporated metal is condensed on an inside surface of the retrieving device which is cooled with cooling water, and condensed metal is cut from the cooled inside surface of the retrieving device with a cutter and is collected. ### Claim 8 (depends on 6) A method according to claim 6, wherein the evaporated metal is condensed and retrieved with a cooled filter disposed within the retrieving device. ### Claim 9 (depends on 6) A method according to claim 6, wherein the evaporated metal is brought into contact a rotating rapid cooling member to be condensed in the form of amorphous and thereafter collected. ### Claim 10 (depends on 1) A method according to claim 1, wherein a reduced pressure generated in the pretreatment chamber is in a range of about 10.sup.-4 -10.sup.-1 mmHg. ### Claim 11 (depends on 1) A method according to claim 1, wherein a reduced pressure generated in the treatment chamber is in a range of about 10.sup.-4 -10.sup.-1 mmHg. ### Claim 12 (depends on 1) A method according to claim 1, wherein said preheating metal plated steel sheet scraps is conducted in air. ### Claim 13 (depends on 1) A method according to claim 1, wherein said preheating metal plated steel sheet scraps is conducted in a non-oxidizing gas environment. ### Claim 14 (depends on 1) A method according to claim 1, wherein the gas with which said cooling the scraps in the cooling chamber is conducted is air. ### Claim 15 (depends on 1) A method according to claim 1, wherein the gas with which said cooling the scraps is conducted in the cooling chamber is non-oxidizing gas. ### Claim 16 An apparatus for removing plated metal from steel sheet scraps comprising: a pretreatment chamber having heating means for heating metal plated steel sheet scraps to a temperature in a range of about 200.degree. C.-500.degree. C. to evaporate organic material adhered to the scraps and contained in the scraps, a pressure reducing pump being connected to the pretreatment chamber via a passage, and a filter for capturing the evaporated organic material being installed in the passage connecting the pretreatment chamber to the pressure reducing pump; a treatment chamber having a heater for heating the scraps from which organic material has been removed to a temperature in a range of about 500.degree. C.-900.degree. C., a pressure reducing pump being connected to the treatment chamber via a passage, and an evaporated metal retrieving device being installed in the passage connecting the treatment chamber to the pressure reducing pump; and a cooling chamber for cooling the scraps. ### Claim 17 An apparatus for removing plated metal from steel sheet scraps comprising: a preheat chamber for preheating metal plated steel sheet scraps; a pretreatment chamber having heating means for heating the preheated scraps to a temperature in a range of about 200.degree. C.-500.degree. C. to evaporate organic material adhered to the scraps and contained in the scraps, a pressure reducing pump for reducing a pressure in the pretreatment chamber being connected to the pretreatment chamber via a passage, and a filter for capturing the evaporated organic material being installed in the passage connecting the pretreatment chamber to the pressure reducing pump; an intermediate chamber through which the scraps from the pretreatment chamber is conveyed; a treatment chamber having a heater for heating the scraps from which organic material has been removed to a temperature in a range of about 500.degree. C.-900.degree. C., a pressure reducing pump for reducing a pressure in the treatment chamber being connected to the treatment chamber via a passage, and an evaporated metal retrieving device being installed in the passage connecting the treatment chamber and the pressure reducing pump; and a cooling chamber for cooling the scraps. ### Claim 18 (depends on 16) An apparatus according to claim 16, wherein the treatment chamber includes: an outer wall; a drum disposed within and rotatably supported by the outer wall, the drum having a plurality of holes therethrough through which an interior and an exterior of the drum are in communication, the scraps being conveyed through the drum; and drive means for rotating the drum. ### Claim 19 (depends on 18) An apparatus according to claim 18, wherein the heating means provided for the treatment chamber is installed to the outer wall of the treatment chamber. ### Claim 20 An apparatus for removing plated metal from steel sheet scraps comprising: a furnace for heating metal plated steel sheet scraps to evaporate plated metal and organic metal adhering to and contained in the scraps; and a retrieving chamber, connected to the furnace, for retrieving a plurality kinds of evaporated material, the retrieving chamber including a plurality of condensing chambers which are respectively controlled in temperature to respective boiling points of the plurality kinds material, the condensing chambers being in communication with each other and being arranged in series so that each condensing chamber is disposed upstream of any condensing chamber for condensing a material having a lower boiling point and downstream of any condensing chamber for condensing a material having a higher boiling point than the material it is adapted to condense. ### Claim 21 (depends on 20) An apparatus according to claim 20, wherein the furnace is connected to a pressure reducing pump via a passage, and the retrieving chamber is installed in the passage connecting the furnace to the pressure reducing pump.