Metal finishing Q&As since 1989

-----

Alkaline zinc

I have problems with alkaline zinc - hanging. He refers to very badly. Content of zinc is 8,5 g/l and NaOH 135 g/l Has perhaps who experience with Protolux 3000?

Vlasta Baùiè
- Maribor, Slovenia
2005

Protolux solutions don't cope well with high concentrations of Sodium Carbonate. If the concentration is above 60 g/l you would expect quite a drop in solution efficiency.

Dougie Lightfoot
- Fife, Scotland
2005

---

First of two simultaneous responses -- 2005

Try to maintain 1:10 ratio Zinc:Sodium Hydroxide.
Ideal composition for vat is 12:120
and for Barrel is 14:140
Needless to say that the additives you use should be from reputed and proven source.
Presently This is not a problem

T.K. Mohan
plating process supplier - Mumbai, India

---

Second of two simultaneous responses --

It sounds to me that your having problems keeping your metal content up. 135 g/l sodium hydroxide is ok but 8.5 g/l sounds a little low.

We help the dissolution of zinc by using zinc domes in mild steel cages. The rust from the mild steel helps lots. I run my non-cyanide zinc tanks with a metal content of about 10-11.5 g/l

Chris Matthews
- East Sussex, England
2005