During the winter months, many regions of the United States, Canada and Europe experience extended periods of cold days and nights. CARUSOL® liquid permanganate and CARUSOL® C liquid permanganate products may be exposed to days of cold temperatures during transportation and storage.
CARUSOL and CARUSOL C products are water solutions and may freeze when exposed to cold weather over many hours. These products are freeze/thaw stable and their solution strengths can be recovered when warmed.
The Permanganate Products Team reminds you that these products contain a small amount of residual potassium ion. When exposed to cold temperatures, small potassium permanganate (KMnO4) crystals may form. These crystals may precipitate out of solution and settle to the bottom of packages and storage containers due to a decrease in the solubility of potassium permanganate at lower temperatures.
The purple needle-shaped KMnO4 crystals can appear at the bottom of totes, drums, or pails in transit or during storage when temperatures are below 13 ºC or 55 ºF. The graph below illustrates the solubility of KMnO4 in 40% sodium permanganate as a function of temperature.
To prevent crystallization, CARUSOL and CARUSOL C shipping containers should be stored in a warm building. If bulk and semi-bulk storage tanks, metering pumps, and feed lines are located outside, these should be heat traced and insulated.
One way to limit the potential existence of permanganate crystals in the bottom of the totes or drums is to mix the contents of the totes or drums briefly prior to transferring to mixing tanks to get the permanganate crystals back into solution.
If sodium permanganate has already been transferred to the mixing tank and there are crystals on the bottom of the tank, add water to the container to assist in solubilizing the crystals back into solution.
CARUSOL® Liquid Permanganate and CARUSOL® C Liquid Permanganate
Exposure to temperatures < 38 oF (3 oC) may cause potassium permanganate crystals to form. Plugging of small diameter suction lines on metering pumps, particulate screens and check valves is possible.
At 21 oF (-6 oC) CARUSOL® Liquid Permanganate may freeze. At 5 oF (-15 oC) CARUSOL® C Liquid Permanganate may freeze.
CARUSOL® and CARUSOL® C Liquid Permanganates are freeze/thaw stable.
This information has been compiled through Quality Control analyses and field data reports and it is meant as a physical-chemical guideline for the use of our customers. It is current and accurate to the best of our knowledge. If you have additional questions or comments, please contact us.