Manganese Deposition

Question

How many plants experience Mn deposition and/or stainless steel under-deposit corrosion due to Mn/Fe deposition?

Ruben D. Hidalgo · Answer

On the other hand, Manganese concentration is controlled at the entrance of the water treatment plant, by precipitation.

Ruben D. Hidalgo · Answer

It depends on the quality of the water entering the process, now if we talk about a recirculation process in industrial services of refineries or steel mills, with an efficient treatment of antiscalant and biodispersants at an adequate pH the deposition is negligible.

Don Sharpe · Answer

This will teach me to read the question.  Approximately 10-20% of closed cooling and chilled systems will have issues with iron or manganese deposits.

Don Sharpe · Answer

I have carried out work investigating manganese deposits on stainless steel and copper.  In nearly all of the samples, bacteria were involved in both the deposition and corrosion.  Clear evidence was found of bacteria being present within the deposits and once these were introduced into fresh samples of stainless steel and copper in the presence of water, they grew and produced fresh deposits.  Stainless colonisation is slower than copper but still occurs.  I am sure that there will be exceptions, but so far the presence of manganese bacteria is the reason for deposits and corrosion.

Norris Johnston · Answer

I believe the answer is simple - where there is Mn in the water and either SS or Cu Alloys are present, there is deposition and subsequent under deposit corrosion.  The severity of the deposits and UDC is more about Mn concentration, oxidizing practices, treatment protocol(s), and equipment performance.

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