I Use of Calcium Magnesium Solutions for Pre-Wetting/Anti-Icing (Direct Liquid Applications)
The past two decades have seen much activity in the use of Calcium/Magnesium Solutions in conjunction with the use of road salt and abrasives for winter snow and ice control. Two common approaches have been used - pre-wetting and anti-icing (or Direct Liquid Applications).
Salt Spray system using saddle tanks on hopper/spreader.
Pre-wetting is the process of treating salt (and in some cases sand) with a solution of sodium, calcium or magnesium chloride, prior to the materials application on the road surface. In most cases this is done by mounting tanks and specially designed spray equipment on salt spreaders that "spray" the salt as it is being dropped onto a spinner.
Approximately 6 to 10 US Gals. are sprayed on 1 ton of salt (approx. 25 to 42 metric tonne). Rates vary for several reasons including temperature, road conditions and expected precipitation, desired effect and others.
Pre-wetting with calcium/magnesium solutions help jump-start the salt into a brine solution so quicker melting and less bonding of materials on the road surface can be observed. In addition the pre-wetting of salt results in less "scatter" on the road. Many studies suggest a savings of 20 to 30% in salt usage can be experienced when wetted salt is compared to non-treated salt. Combining this savings with a road surface that can be safer from less snow/ice bonding are making pre-wetting increasingly popular in urban areas with high traffic volumes.
Since calcium solutions have a much lower eutectic point than sodium chloride solutions it can be handled and stored with significantly less crystallization than sodium chloride alone. Crystallization can easily plug spray systems and must be a consideration as temperatures drop. Liquid calcium solutions at 29% strength can remain liquid at temperatures below -40F (-40C). Sodium solutions alone will only remain unfrozen when blended to 23% solution at temperatures no colder than -21% (-5F). While these temperatures don't seem to be a concern they have to be considered since dilutions after application can rapidly deteriorate the effectives and may contribute to re-freeze as dilution occurs.
Untreated rock salt loses effectiveness significantly when temperatures drop below 20F ( -7C) and is practically ineffective below 15F (-10F). Calcium solutions can dramatically improve the salt's performance at these lower temperatures due to the superior melting ability in its chemical properties.
B) Anti-Icing/Direct liquid Applications
Anti-icing or direct liquid applications include the intentional spraying of calcium/magnesium or sodium chlorides on paved roads immediately before a winter event or expected winter event. While expected snowfall or freezing rain are the normal "events" this application is sometimes made in late fall/early winter to prevent the formation of black ice due to frost at certain locations subject to such when temperatures fluctuate at the freezing point.
Application rates are significantly lower than any other use of the chlorides and range between 40 and 100 liters per lane kilometer. There are strict conditions to monitor and observe to determine the appropriate time and application rate which local engineering staff should determine in conjunction with the road and environmental information system specific to the area of application. Very specialized application equipment is required to ensure proper application rates but much is similar in design to that used for spreading fertilizers on farm acreage.
This process is not for melting accumulated precipitation but is intended to prevent the bonding of expected moisture from frost, snow, ice or freezing rain to the roadway so the road surface can be returned to bare condition as soon as possible.
The characteristic of all chloride liquids must be compared and used accordingly. handling, Ice-melting features, reaction time and residual conditions are all factors to be examined when using ant-icing/direct liquid techniques.
General Benefits of Pre-wetting/Anti-icing (or Direct Liquid) Applications vs. No Treatments
Savings in Salt Consumption
Safer Roads for Travel
Quicker return to bare roads
Overall reduction in total chloride usage (environmental consideration)
Reduced clean-up costs when compared to abrasives (sweepers and related equipment/manpower)
Reduced costs/maintenance due to abrasives which prematurely plug drains and sewers.
Reduced wear and tear on snow removal equipment since snow can be removed more easily - less bonding on road surface - fewer passes to get roads bare.
II Other Freeze - Proofing / Thawing
Mining / Railways / Aggregate Haulers and Aggregate Storage
The superior storage and melting abilities of Trillium's calcium products over sodium brines offers solutions to industries that face unique material handling issues when temperatures drop.
Winter Calcium solution being supplied to Northern Ontario Mine for thawing/freeze-proofing ores before heading into crusher.
Trillium's Winter Products are effective in applications to melt frozen ores at mine sites or for thawing frozen railcars contain ores or ballast. They can also be used to help reduce crushing related costs when applied to partially frozen ores in stockpiles or in material handling conveyors or hoppers prior to crushing or to help prevent solidifications due to freezing after crushing, or while in storage.
The Use of Winter Calcium can also increase payloads thereby reducing freight costs when treating railcars or dump equipment when temperatures and moisture otherwise cause build-up of materials and line the boxes and/or railcars or other storage containers.
III Trillium Solution - Winter Products
Trillium's Winter Products can satisfy the unique needs of those requiring pre-wetting, anti-icing (direct liquid application) or freeze-proofing and thawing for many situation. A Trillium representative would be happy to assess your specific conditions and needs and recommend an appropriate solution tailored for you.