Any metal having a low ?-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an ?-ray after heating the metal at 100? C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an ?-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

A device for preparing ultra-high purity zinc based on intelligently-controlled zone melting, including a slide platform connected with a screw through a servo control system to control movement of a heating-cooling device. A quartz tube is provided inside an induction heater to protect a melting zone. An infrared thermometer is connected to the heater, and configured to monitor temperature within the melting zone, and control power of the heater. A ring magnetic stirrer with non-contact circumferential rotation cooperates with coil to stir zinc melt. A water-cooling copper jacket is connected to two ends of the heater to cool a zinc bar, and its water inlet and outlet are connected with a water chiller. The infrared thermometer monitors temperature of the zinc bar and controls water flow of the cooling system. A lifting device is connected with a base cabinet to change inclined angle of the zinc bar.

A device for preparing ultra-high purity zinc based on intelligently-controlled zone melting, including a slide platform connected with a screw through a servo control system to control movement of a heating-cooling device. A quartz tube is provided inside an induction heater to protect a melting zone. An infrared thermometer is connected to the heater, and configured to monitor temperature within the melting zone, and control power of the heater. A ring magnetic stirrer with non-contact circumferential rotation cooperates with coil to stir zinc melt. A water-cooling copper jacket is connected to two ends of the heater to cool a zinc bar, and its water inlet and outlet are connected with a water chiller. The infrared thermometer monitors temperature of the zinc bar and controls water flow of the cooling system. A lifting device is connected with a base cabinet to change inclined angle of the zinc bar.

A method for recycling zinc (Zn), wherein the method comprises the following steps: providing a feed composition; adding the feed composition to a rotary oven; heating the added feed composition for producing a first liquid molten metal phase and a first supernatant dross; adding aluminum (Al) to the first liquid molten metal phase, wherein a second supernatant dross and a second liquid molten metal phase are formed; adding at least one flux to the second liquid molten metal phase, followed by at least one segregation step in which the second liquid molten metal phase is removed from the rotary oven; casting the second liquid molten metal phase, or adding the removed second liquid molten metal phase to a casting furnace; casting the second liquid molten metal phase from the casting furnace; wherein the method further comprises the steps of: removing the second supernatant dross from the rotary oven; subjecting the removed second supernatant dross to at least one crushing step and at least one sorting step for separating at least one zinc fraction and at least one zinc oxide fraction from the second supernatant dross; and using the at least one zinc fraction for contributing to provide the feed composition.

The present disclosure discloses a method for refining an iron oxide that is a by-product of a zinc smelting process, the method including a roasting process of roasting the iron oxide, a washing process of washing a roasted iron oxide cake with a washing water, and a filtering process of filtering the washed iron oxide cake, thereby providing refined iron oxide.

The present disclosure discloses a method for refining an iron oxide that is a by-product of a zinc smelting process, the method including a roasting process of roasting the iron oxide, a washing process of washing a roasted iron oxide cake with a washing water, and a filtering process of filtering the washed iron oxide cake, thereby providing refined iron oxide.

The present disclosure provides a method for removing chlorine from a process solution in zinc hydrometallurgy, the method comprising: a step for preparing the process solution from a leaching process of leaching a zinc calcine; a step for introducing the process solution to a reactor and introducing a lead concentrate into the reactor while blowing-in oxygen; a step for solid-liquid separating of a slurry in a filtration tank, the slurry being produced in the reactor; and a step for post-processing a filtrate and a lead concentrate residue separated in the step for solid-liquid separating, wherein chlorine ions in the process solution and silver contained in the lead concentrate react with each other in the reactor to precipitate a silver chloride.

A zinc production method includes a reaction step such as a leaching step (101) of bringing electric arc furnace dust (1) containing zinc oxide or the like into contact with a chlorine gas (8) to obtain a zinc oxide component in the electric arc furnace dust (1) or the like as crude zinc chloride (3), a purification step (102) of heating the crude zinc chloride (3) obtained at the reaction step to produce zinc chloride vapor, and cooling and condensing the zinc chloride vapor, thereby obtaining purified zinc chloride (6), and an electrolysis step (103) of electrolyzing the purified zinc chloride (6) obtained at the purification step (102) in a molten state to obtain a zinc melt (9) and the chlorine gas (8).

A zinc production method includes a reaction step such as a leaching step (101) of bringing electric arc furnace dust (1) containing zinc oxide or the like into contact with a chlorine gas (8) to obtain a zinc oxide component in the electric arc furnace dust (1) or the like as crude zinc chloride (3), a purification step (102) of heating the crude zinc chloride (3) obtained at the reaction step to produce zinc chloride vapor, and cooling and condensing the zinc chloride vapor, thereby obtaining purified zinc chloride (6), and an electrolysis step (103) of electrolyzing the purified zinc chloride (6) obtained at the purification step (102) in a molten state to obtain a zinc melt (9) and the chlorine gas (8).

A method for removing lead-210 (.sup.210Pb) from a metal, the method comprising determining a .sup.210Pb concentration in a metal to be refined; determining an amount of low alpha lead to be added to the metal to be refined from the .sup.210Pb concentration, the low alpha lead having a .sup.210Pb concentration below that of the metal to be refined; forming a doped metal mixture by adding the low alpha lead to the metal to be refined; refining the doped metal mixture to separate at least a portion of the lead in the doped metal mixture to form a refined metal having a .sup.210Pb concentration lower than that of the metal to be refined.