Filter Sheets CKP

Our new application in galvanic sector

In 2019, as a part of OMG Research and Development activity, the attention was focused on the matter of the presence of Sn colloidal suspensions in the galvanic nickel plating baths.

Currently, these suspensions are intercepted by a resin system, whose regeneration represents an operation which is the more onerous the shorter is the time between an event and another one.

To point out, “an exchange resin ion is composed of a polymer matrix (usually made of few millimeters in diameters granules) in which ions, available for ion exchange, are trapped or embedded.

There are a lot of ion exchange resins, most of them are based on polystyrene, generally cross-linked with di-vinylbenzene, to which functional groups, capable of capturing or releasing ions, are also added "(from Wikipedia).

When the resins become saturated, they must be regenerated. Therefore, they are removed from the plant, immersed in the suitable reagent and ground (since with the use they tend to join as blocks), treated, in time or volume mode, with a regenerating solution rich in the same ions type that the resins lost during the ion exchange.

Referring to Sn, it should be remembered that it was a well known metal in ancient times. Its ability to bond with Cu to form the bronze, with its characteristics of hardness and malleability, has given an important boost to human development (Bronze Age, from the third millennium B.C.). Nowadays Sn is used in food and construction sectors as an anti-corrosion coating, in the electrical and electronic industries to the manufacture of printed circuits and for the electronic components welding.

In electronics industry, Sn and its alloys with Pb are regulated on the European directives 2002/95 / EC and 2002/96 / EC. In fact, if the Sn is higher than the allowed limits, it could cause eyes and skin irritations, migraines, stomach pains, difficulty in urinating.

Therefore, the filter pump has the objective of intercepting the colloidal particles containing Sn in the electrolytic solution, acting as a supporting system of the resins action, in order to reduce pollution.

The new developments in the current situation concern the adding of a filtration phase in the galvanic process of nickel plating with the specific purpose of retaining the colloidal particles of Sn, which pollute the resins, making their regeneration necessary.

From these premises, O.M.G. has started an internal study and an evaluation analysis in order to develop a new application: a new filtration system.

In order to carry out this research activity, the TE5 filter pump (characterized by a square base tank) was chosen.

The filtering block was designed and built allowing the use of dicalite CKP filter sheets, square format 310x310 mm, provided by our official supplier, Cartiera Gruppo Cordenons. Carbon filters of the same format, were added too.

The TE5 filtering pack prototype, has made possible to achieve significant colloidal Sn particles retaintion, reducing the number of resin regenerations per unit time.

A twofold result was achieved: costs reduction and decrease of issues relating to the European Directives compliance, as mentioned above.