Mitsubishi Materials Corporation

Hirotaka Hirano

Takuma Katase

Koji Tatsumi

Kyohei Mineo

Yoshihiro Yoshida

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/cmor 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/cmor 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.

Metal and tin alloy having low alpha-ray emission, and method for producing same

The present invention provides a high-concentration tin sulfonate aqueous solution, in which a divalent tin ion (Sn) concentration is 360 g/L to 420 g/L, a tetravalent tin ion (Sn) concentration is 10 g/L or less, a free methanesulfonic acid concentration is 40 g/L or less, a Hazen unit color number (APHA) is 240 or less, and a turbidity is 25 FTU or less. This aqueous solution is produced such that stannous oxide powder whose temperature is adjusted to a temperature of 10&#xb0; C. or lower is added to an aqueous methanesulfonic acid solution having a concentration of 60% by mass to 90% by mass when the aqueous solution circulates in a state of being maintained at the temperature of 10&#xb0; C. or lower, and the stannous oxide powder is dissolved.

High-concentration tin sulfonate aqueous solution and method for producing same

A stannous oxide powder which has a high dissolution rate into various acid solutions such as a plating solution and is particularly suitable as a Sn supply material to a plating solution, and a method for producing the stannous oxide powder are provided. The stannous oxide powder is a particle body having a plurality of plate-like protrusions protruding outward, and has an average particle size in a range of 1 &#x3bc;m to 15 &#x3bc;m.

Stannous oxide powder and method for producing stannous oxide powder

The method of producing stannous oxide includes: a Sn ion-containing acid solution forming step (S); a first neutralizing step (S), which is a step of forming Sn precipitates by adding one or more of alkaline solutions of ammonium carbonate, ammonium bicarbonate, and aqueous ammonia to the Sn ion-containing acid solution to retain pH at 3-6 therein; a Sn precipitate separating step (S); a Sn precipitate dispersing step (S), which is a step of dispersing the separated Sn precipitates in a solvent liquid to obtain a dispersion liquid; and a second neutralizing step (S), which is a step of forming SnO by adding an alkaline solution to the dispersion liquid of the Sn precipitates and then by heating, wherein Na, K, Pb, Fe, Ni, Cu, Zn, Al, Mg, Ca, Cr, Mn, Co, In, and Cd reside in the Sn ion-containing acid solution in the first neutralizing step (S).

Growing community of inventors

Sanda, Japan

Hirotaka Hirano