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In the Mix
Posted By peterschemical On 04/15/2011 @ 8:13 am In | No Comments
IN THE MIX
In a number of recent columns, I have written about the various ingredients that make up commercial de-icing agents. Many vendors have what they call proprietary blends of various ingredients, particularly when selling it by the bag. Often, many of these vendors tend to be very sketchy about exactly how much of each ingredient is in their mixture. They consider it “proprietary information” and not subject to disclosure.
Typically, however, there are up to five categories of materials in different combinations:
1. The main melting agent (e.g. salt)
2. An additional melting agent (e.g. calcium chloride or magnesium chloride)
3. A corrosion-inhibiting agent
4. Sometimes an organic or inorganic compound intended to improve the melting capacity and/or reduce corrosion
One major supplier of bagged products, Cargill Salt, is bucking the trend of non-disclosure and will provide a complete list of ingredients in its product line this winter. This is a major step forward in providing the information needed for users to make intelligent decisions on purchases.
Why it is important:
For many reasons, it is crucial to the user to know exactly what’s in the mix and what the ingredients do for you in terms of performance. When performance is known, it can be compared with the purchase price and allows you to make an informed purchase decision.
Melting performance: If melting performance is the major concern, then the total amount of known and understood melting agents should be taken into consideration. In this case, the SDMA (Super Duper Melting Agent) is an unknown and should be ignored. If Product 1 has 93% salt and 2% calcium chloride and Product 2 as 88% salt and 2% calcium chloride, Product 1 would be your better choice, assuming equal costs.
The effects of melting enhancers are much harder to quantify as to their actual effect on performance, and are often the basis of huge claims. Once again, independent data about that ingredient and its performance as part of the mix is the only way to know for sure. A phase curve for the product as a mixture from an independent laboratory is often the best guide when performance of all kinds is compared with straight salt. This will reveal whether the extra purchase price is really worth it. For example, what if the melting performance is up by 20%, but the price is higher by 60%?
Corrosion issues: If corrosion is one of your major issues, you need to look at the amount and type of corrosion inhibitor in the material and what it really does. Ideally, the product has been tested by an organization such as the Pacific Northwest Snowfighters (PNS), and information about it is available. If it is, you will be able to quickly judge which product is better in terms of corrosion. In our example, it would appear that Product 2—with three times as much corrosion inhibitor—would be the better choice. However, while this product offers lower corrosion, the melting performance is also lower, so is it worth the cost?
Environmental issues: When it comes to environmental issues, not only is the amount of each ingredient important, but the chemical composition of those ingredients is also extremely important. Refer to any testing done by organizations such as PNS to determine whether there’s some ingredient of concern. Ingredients of concern are only determined by assessing your specific environmental issues, such as water quality. With an assessment of environmental concerns, the product that best fits your needs from those available can be determined. Ingredient information can also be found in the product’s material safety data sheet (MSDS), which should be provided by the vendor.
Know what you’re buying:
When buying blended materials, know exactly what is in the products being considered and what they do in terms of corrosion, performance and the environment to select the product that best fits your needs. The more detailed information about a product available, the better. Hopefully, the full disclosure process undertaken by Cargill becomes an industry standard, rather than the exception. Relying on the “proprietary information” crutch allows suppliers to put the buyer at their mercy as to how the product will actually perform and its true value. There is a lot of benefit to knowing exactly what to expect from a product when purchased. With that, paying a bit more for a product with known ingredients and percentages of each seems prudent rather than betting on the unknown.
Dale Keep owns Ice & Snow Technologies, a training and
consulting company based in Walla Walla, WA.
Resource: Pacific Northwest Snowfighters—www.wsdot.wa.gov/partners/pns/
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