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Stainless steel corrosion by chlorine dioxide/sulfuric acid?

 

I'm looking for a good construction materials for pulp bleaching equipment, i.e. pipes, pumps and mixers. We have a pulp-water mixture with 10% pulp consistency. The water phase contains chlorine dioxide, 0.5 g/l and sulfuric acid, 1.5 g/l. Can you give me a list of materials that suits our application? We have some equipment in SS317. Is this material good enough for our application?

Thanks in advance,

Jonas Larsson
chemicals - Bohus, Sweden

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Dear Jonas,

I am strongly believe that the best choice for the application here is titanium alloy. It is not so expensive as it seemed to be. A lot of equipment is produsing for ClO2 solutions. For acid-containing Cl- media we use more expensive zirconium.

Andrey Igolkin
- St.Petersburg, Russia

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Hi Jonas,

Your 'water' content of v. low Cl02 and sulfuric concentrations sounds pretty inocuous and I would have felt that s.s 3l6/7 would have been OK.

For piping perhaps you might like to consider PVC but then outdoors/impact/highish temperatures/freezing ... are negatives. There's also PVDF which is good for up to l40 degr. C with an only drawback of not liking pH's in the l0 and higher range. And as you may know, you could get prefabricated PVDF pipe with a fibreglass BONDED structural reinforcement. .... same thing applies to PVC, too.

Titanium sounds excellent ... but you'd have to sell your Volvo to afford it!

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

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I think you are probably looking at corrosion from nascent chlorine and in my experience the only product that will give satisfactory performance is a high nickel alloy called "Hastelloy C " It is expensive and difficult to work but it is resistant to the environment you are working in.

Regards,

John Tenison - Woods
- Victoria Australia

is PVDF resistant to chlorine dioxide?

Peter campbell
supplier - london england
October 15, 2009

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