C.uyemura Co., Ltd.

Taihei Chemical Industrial Co., Ltd.

Ken Araki

Yutaka Sugiura

Hiromitsu Sakai

Hidemi Nawafune

Shozo Mizumoto

Akemi Kinoshita

Sowjun Matsumura

Takashi Furui

Teruyoshi Izawa

Tamotsu Kato

Masumi Tanigawa

Yoshihiro Kani

Tetsuo Otaka

Kazunori Kudo

Valuable substances are recovered from a spent electroless nickel plating solution containing a water-soluble nickel salt, organic complexing agent, hypophosphite, phosphite, and alkali metal ion by adding oxalic acid to the plating solution for causing a nickel ion to precipitate as nickel oxalate for removal and recovery; optionally adding a sulfide to the plating solution for causing a heavy metal ion to precipitate as a heavy metal sulfide for removal; adding a mineral acid and calcium oxide, calcium hydroxide, calcium carbonate, calcium sulfate, calcium chloride or a calcium salt of organic acid to the plating solution from which the nickel ion has been removed; firing solids of the solution in air for converting the alkali metal ion into an alkali metal salt of mineral acid, converting phosphorus into hydroxyapatite, and pyrolyzing off the organic material; and pouring a solid mixture of the alkali metal salt of mineral acid and hydroxyapatite into water for dissolving the alkali metal salt of mineral acid in water for separate recovery of hydroxyapatite and the alkali metal salt of mineral acid.

Recovery of valuable substances

An electroless copper plating bath is prepared by adding both a metal-cyano-complex used as a stabilizer and an agent for complexing the metal of the metal-cyano-complex to an electroless copper plating bath containing cupric ion, an agent for complexing the cupric ion and a reducing agent, and an article to be plated is immersed in the bath.

Electroless copper plating bath and method

An analytical method for determining by potentiometric titration formaldehyde in an electroless copper plating bath, which comprises using a hydroxylamine salt such as hydroxylamine hydrochloride as the titrant and using a silver electrode as the indicator electrode. This method can determine free formaldehyde in low concentration which takes part in the plating reaction.

Analytical method for determining formaldehyde in electroless copper

A method for codepositing a water-insoluble material with a metal from a plating solution having the metal ion dissolved and the water-insoluble material suspended therein, characterized by pumping at least one third per minute of the volume of the plating solution by means of a pump without entraining air bubbles, and injecting the thus pumped volume downward into the bath through a plurality of holes in the lower side of a sparger pipe connected to said pump and located at a lower level in a plating tank, thereby circulating and fluidizing the plating solution in which codeposition is being carried out.

Codeposition method

A method and an apparatus for controlling the content of an electroless plating bath such as an electroless nickel plating bath such that the bath is useable for an extended period of time without remaking are disclosed. The method comprises the steps of:

Apparatus for controlling electroless plating bath

A method and an apparatus for controlling the content of an electroless plating bath such as an electroless nickel plating bath such that the bath is usable for an extended period of time without remaking are disclosed. The method comprises the steps of: continuously or intermittently measuring the concentration of at least one consumable ingredient of the electroless plating bath, and automatically adding to the plating bath a first replenishing composition essentially consisting of the consumable ingredient after detecting that the measured value has reached a predetermined concentration; while continuously or intermittently measuring one physical property of the electroless plating bath to determine the degree of aging of the bath, and automatically discharging a predetermined volume of the plating solution and automatically adding to the plating bath a second replenishing composition containing unconsumable ingredients in an amount essentially corresponding to the lost amount by the discharging after detecting that the measured value has reached a predetermined value of the physical property.

A method and an apparatus for controlling an electroless plating bath such as an electroless nickel plating bath capable of using the bath for an extended period of time without remake are disclosed. The method comprises the steps of

A method and an apparatus for controlling an electroless plating bath such as an electroless nickel plating bath such that the bath is useable for an extended period of time without remaking are disclosed. The method comprises the steps of:

Method for controlling electroless plating bath

A method and an apparatus for controlling an electroless plating bath such as an electroless nickel plating bath capable of using the bath for an extended period of time without remake are disclosed. The method comprises the steps of:

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Ibaragi, Japan

Ken Araki