This invention provides a cost-effective hot-dip galvanization process for ferrous metals, which is regardful to the environment and to the health of the personnel.

This invention provides a cost-effective hot-dip galvanization process for ferrous metals, which is regardful to the environment and to the health of the personnel.

A manufacturing method of a support for a planographic printing plate including at least an alkaline etching step of dissolving an aluminum surface layer of an aluminum web with an alkaline solution during a surface roughening treatment on a surface of the aluminum web continuously traveling, the manufacturing method comprising: a circulating step of cyclically using the alkaline solution between a treatment tank for the etching and an alkaline solution reservoir during adjusting composition concentration of the alkaline solution; and a filtering step of filtering the alkaline solution cyclically used so as to remove solid matter in the alkaline solution.

A manufacturing method of a support for a planographic printing plate including at least an alkaline etching step of dissolving an aluminum surface layer of an aluminum web with an alkaline solution during a surface roughening treatment on a surface of the aluminum web continuously traveling, the manufacturing method comprising: a circulating step of cyclically using the alkaline solution between a treatment tank for the etching and an alkaline solution reservoir during adjusting composition concentration of the alkaline solution; and a filtering step of filtering the alkaline solution cyclically used so as to remove solid matter in the alkaline solution.

This invention provides a cost-effective hot-dip galvanization process for ferrous metals, which is regardful to the environment and to the health of the personnel.

This invention provides a cost-effective hot-dip galvanization process for ferrous metals, which is regardful to the environment and to the health of the personnel.

An acidic treatment liquid processing apparatus includes: a tank having an interior space; a diaphragm permeable to a metal cation and separating the interior space of the tank into a first chamber and a second chamber; a first electrode disposed in the first chamber; a second electrode disposed in the second chamber; a power supply configured to apply a voltage while using the first electrode as an anode and the second electrode as a cathode; a first liquid passing part configured to pass an acidic treatment liquid containing a dichromate ion and a metal cation into the first chamber; and a second liquid passing part configured to pass an acid aqueous solution into the second chamber.

An acidic treatment liquid processing apparatus includes: a tank having an interior space; a diaphragm permeable to a metal cation and separating the interior space of the tank into a first chamber and a second chamber; a first electrode disposed in the first chamber; a second electrode disposed in the second chamber; a power supply configured to apply a voltage while using the first electrode as an anode and the second electrode as a cathode; a first liquid passing part configured to pass an acidic treatment liquid containing a dichromate ion and a metal cation into the first chamber; and a second liquid passing part configured to pass an acid aqueous solution into the second chamber.

Method for recovering Cr from a pickling bath of an aqueous solution containing sulphate and Cr from a pickled metal, the method including: forming an aqueous two-phase system from a portion of the pickling bath and a polymer including an unhindered ether function, the proportion of polymer in the ternary mixture including the pickling bath, considered to be a unique chemical component, water and polymer, ranging between the line of the equation weight % of polymer=100%weight % of pickling bath and the binodal curve of the pickling bath/polymer mixture, the two-phase aqueous system including polymer and non-polymer phases; separating the respective phases; allowing precipitates containing Cr to form in the polymer phase; carrying out solid/liquid separation of the polymer phase to separate the polymer and the precipitates containing Cr; and processing the precipitates to recover the Cr. A facility is also disclosed.