# US 9,751,035 B2 · Operation method for dezincification plant > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,035 B2 - Document ID: US9751035B2 - Status: Granted - Kind: B2 - Application number: 14/760,066 - Filed: 2013-12-10 - Published: 2015-12-10 - Granted: 2017-09-05 - Earliest claimed: 2013-01-10 - Assignees: Sumitomo Wiring Systems, Ltd. - Applicants: Sumitomo Metal Mining Co., Ltd. - Inventors: Hiroyuki Mitsui; Satoshi Matsubara; Osamu Nakai - Web page: https://patentgrep.com/patent/US9751035B2 ## CPC - B01D 37/04: Controlling the filtration - C01G 9/08: Sulfides - C22B 1/00: Preliminary treatment of ores or scrap - C22B 23/043: {Sulfurated acids or salts thereof} - C22B 23/0461: {by chemical methods} - Y02P 10/20: Recycling - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20) - C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract At the beginning of a dezincification plant used in a dezincification step in a hydrometallurgical method for nickel, a decrease throughout the dezincification plant is controlled to prevent a decrease in production volume and a cake layer is formed on a filter cloth provided to a filter device inside the dezincification plant. At the beginning of dezincification plant, a slurry containing a formed zinc sulfide is supplied to a filter for filtration and separation, an adjustment is performed in which the flow rate of the slurry is increased to reach a target flow rate in a time T2 which satisfies the following relational expression 3×T1≦T2≦5×T1, where T1 represents the time between starting a slurry supply and attaining the target flow rate in the case of transferring the slurry at the maximum liquid transfer capacity of a pump configured to transfer the slurry. ## Claims ### Claim 1 An operation method for a dezincification plant, the method comprising: leaching a nickel oxide ore containing zinc, nickel and cobalt; neutralizing of the leachate of the nickel oxide ore containing zinc, nickel and cobalt to obtain a post-neutralization solution; applying a sulfurization treatment to the post-neutralization solution to form a zinc, sulfide; and separating and removing the zinc sulfide, wherein, when, upon start-up of the dezincification plant, a slurry containing the zinc sulfide formed by adding a sulfurizing agent to the post-neutralization solution is supplied to a filter for filtration and separation, an adjustment is performed in such a manner that a flow rate of the slurry supplied to the filter is increased in stages to reach a target slurry flow rate in a time T2, which satisfies the following relational expression (i), 3×T1≦T2≦5×T1 (i) where T1 represents a minimum time between starting a slurry supply and attaining the target slurry flow rate in the case of transferring the slurry at a maximum liquid transfer capacity of a pump configured to transfer the slurry. ### Claim 2 (depends on 1) The operation method for the dezincification plant according to claim 1, wherein each of the stages has a step of increasing a slurry flow rate and a step of maintaining a slurry flow rate. ### Claim 3 (depends on 2) The operation method for the dezincification plant according to claim 2, wherein, in the step of increasing the slurry flow rate in each of the stages, said slurry flow rate is increased by transferring the slurry at the maximum liquid transfer capacity of the pump. ### Claim 4 (depends on 1) The operation method for the dezincification plant according to claim 1, wherein the slurry flow rate is adjusted so as to be increased in three stages to six stages. ### Claim 5 An operation method for a dezincification plant, the method including a hydrometallurgical method for a nickel oxide ore comprising: a leaching step wherein sulfuric acid is added to a slurry of the nickel oxide ore to perform leaching under high temperature and high pressure; a solid-liquid separation step wherein multistage washing is applied to the slurry to separate a residue therefrom, whereby a leachate containing an impurity element together with nickel and cobalt is obtained; a neutralization step wherein a pH of the leachate is adjusted to separate a neutralized precipitate containing the impurity element therefrom, whereby a post-neutralization solution containing zinc together with nickel and cobalt is obtained; a dezincification step wherein a sulfurization treatment is applied to the post-neutralization solution to form a zinc sulfide, and said zinc sulfide is separated therefrom to obtain a mother liquor for nickel recovery which contains nickel and cobalt; and a nickel recovery step wherein a sulfurization treatment is applied to the mother liquor for nickel recovery to form a mixed sulfide containing nickel and cobalt, wherein, when, upon start-up of the dezincification plant, a slurry containing the zinc sulfide formed by adding a sulfurizing agent to the post-neutralization solution is supplied to a filter for filtration and separation, an adjustment is performed in such a manner that a flow rate of the slurry supplied to the filter is increased in stages to reach a target slurry flow rate in a time T2, which satisfies the following relational expression (i), 3×T1≦T2≦5×T1 (i) where T1 represents a minimum time between starting a slurry supply and attaining the target slurry flow rate in the case of transferring the slurry at a maximum liquid transfer capacity of a pump configured to transfer the slurry.