Any metal having a low α-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an α-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 α-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 solid metal flux comprised of compacted granules including (a) alkali chloride salt, (b) alkaline earth chloride salt and (c) at least one nitrate, carbonate, or sulfate salt and/or a fluoride containing salt.

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 a-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.

Ultrasonic probes containing a plurality of gas delivery channels are disclosed, as well as ultrasonic probes containing recessed areas near the tip of the probe. Ultrasonic devices containing these probes, and methods for molten metal degassing using these ultrasonic devices, also are disclosed.

Ultrasonic probes containing a plurality of gas delivery channels are disclosed, as well as ultrasonic probes containing recessed areas near the tip of the probe. Ultrasonic devices containing these probes, and methods for molten metal degassing using these ultrasonic devices, also are disclosed.

Ultrasonic probes containing a plurality of gas delivery channels are disclosed, as well as ultrasonic probes containing recessed areas near the tip of the probe. Ultrasonic devices containing these probes, and methods for molten metal degassing using these ultrasonic devices, also are disclosed.

Ultrasonic probes containing a plurality of gas delivery channels are disclosed, as well as ultrasonic probes containing recessed areas near the tip of the probe. Ultrasonic devices containing these probes, and methods for molten metal degassing using these ultrasonic devices, also are disclosed.

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.