Icemelting FAQs
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What different types of ice melters are there?
Ice melters are available in pellets, granules, flakes or liquid - granules being the best format. Flaked forms don't penetrate as deep as granules, and therefore don't liquefy beneath surface of ice, nor do they apply well in windy conditions.
According to researchers at Iowa State University, there are five chemicals commonly used as de-icers (among others). Alternative de-icers claiming to be more environmentally friendly are often a combination of these five chemicals blended to minimize environmental risks while optimizing performance and cost-effectiveness. Understanding the properties of these chemicals and other compounds can help you decide which de-icer best suits your circumstances:
The various types of ice melter compounds include:
- Rock salt or sodium chloride (NaCl) - draws heat from the environment rather than releasing it and it loses most of its deicing effectiveness when temperatures are below -4° C (25° F).
- Magnesium chloride (MgCl2) - is also known as a corrosive agent, but when utilized as a de-icer, other chemical agents are added to reduce and minimize this potential, but the corrosive attributes cannot totally be removed. Another concern is its reaction with aluminum and galvanized steel, metal hardware and electrical conductors.
- Urea (fertilizer) nitrogen (NH2CO NH2) is synthesized from ammonia and carbon dioxide. It is primarily used as a fertilizer. As a deicer, it has a lower burn potential than potassium chloride. Application rate is 4.5 kg (10 lbs) per 30 sq. metres (100 sq. ft). Melts ice at temperatures as low as -11.5° C (11° F), but works best applied at -4° C to -1° C (25-30° F).
- Calcium chloride (CaCl2) - is more effective ice melter than urea, but runoff can damage plants and vegetation. Mixing one part calcium chloride to three parts sawdust helps control runoff. Available in flake, pellet, or liquid form and often outperforms other de-icing products especially at lower temperatures. It produces an exothermic reaction, giving off heat as it melts. Calcium chloride also has a greater capacity to attract and retain moisture directly from its surroundings, which enables it to dissolve faster and start the melting process.
- Potassium chloride - is a naturally occurring material that is also used as a fertilizer (muriate of potash) and a food salt substitute. Because of its high salt index and the potential to burn foliage and inhibit rooting, its use is relatively limited.
- Calcium magnesium acetate (CMA) is a relatively new salt-free melting agent made from dolomitic limestone and acetic acid. It causes little damage to concrete or plants and is used as an alternative to salts in environmentally sensitive areas.
- Gravel, sand, sawdust - can be applied for traction only, or combined with urea or calcium chloride to help decrease chemical runoff rates (ashes, wood chips and/or cat litter are other options).
Some ice melters are simply variations of these basic types, blended with a non-icemelting additive for marketing purposes. Many products sold today are simply re-bagged commodities of rock salt, natural or artificially coloured.
Some ice melters contain potassium, a fundamental ingredient in fertilizers. Potassium is an essential and primary nutrient required by all plants. Tests have found that potassium, unlike sodium or salt, has no harmful effects to soil structure. In fact, potassium even has a counteracting effect to the impairments of salt, thus acting to repair damaged soil. Potassium can also be used where contamination of ground or surface water with sodium is of concern.
What is an ice melter actually supposed to do?
Ice melters help to remove ice by breaking it down, first into smaller chunks and finally into a liquid.
At what temperature are ice melters really necessary?
Snow and ice storms generally occur between the temperatures of -18° and 0° C (0° and +32° F). This is when ice melters will effectively melt ice and snow.
What type of ice melter should be used on new concrete?
No ice melter should be used on newly poured concrete, as this concrete requires a certain length of time to cure. It is best to not use ice melter on new or unsealed concrete less than 12 months old, exposed aggregate, brick, or pre-cast steps. Applying ice melter to damaged, cracked or chipped concrete may result in further damage due to the thaw and re-freeze cycles.
Avoid using calcium chloride ice melter
- Discolouration of concrete
- Hygroscopic, meaning that it attracts or absorbs moisture
- Limited shelf life
- Leaves behind oily residue tracked into buildings, soiling and damaging carpets and flooring
- Very harmful on environment - damaging effect on plants, soil and water supply
- Causes irritation and painful burning to the skin.
Some ice melters are simply variations of these basic types, blended with a non-icemelting additive for marketing purposes. Many products sold today are simply re-bagged commodities of rock salt, natural or artificially colored.
What forms are ice melters available in and what is best?
Ice melters or de-icers are available in pellets, granules, flakes or liquid, with granules being the best format. Flaked forms are best avoided for two reasons: first, they do not penetrate as deep as granules, and therefore don't liquefy beneath the surface of the ice, and secondly, they generally do not apply well in windy conditions. Pellets also have been known to have this problem. Some people have mentioned that pellets, being rounded, tend to roll away under stormy conditions.
People have been using sodium chloride - more commonly known as salt - to meet their icemelting needs for years. Salt has an enormously negative effect on the environment around us, as it is toxic to vegetation and damaging to the soil. Salt has no nutrimental value. The general impact of salt on crops or vegetation is to reduce growth. It does this by promoting high pH values that cause micronutrient deficiencies.
Sodium (Na) or salt is not only harmful to plant life, but also to the very soil that sustains life. Salt content in soils disperses both the clay particles and organic matter. This breakdown in the soil's aggregate structure reduces its permeability to air and water. As a result, root proliferation and penetration throughout the soil volume is impaired. Also, when these soils dry, they become hard and cloddy with a tendency to form heavy surface crusts.
With our environment deteriorating around us, it is no wonder that many people are turning to alternative ice melters to meet their needs. Some ice melters contain a large percentage of potassium (K), which is a fundamental ingredient in fertilizers. Potassium is an essential and primary nutrient required by all plants. Tests have found that potassium, unlike sodium or salt, has no harmful effects to soil structure. In fact, potassium even has a counteracting effect to the impairments of salt, thus acting to repair damaged soil. Potassium can also be used where contamination of ground or surface water with sodium is of concern.
Which chemical ice melters harm or even discolour concrete?
Some ice melters containing the additives of ammonium nitrate or ammonium sulphate will rapidly disintegrate concrete and therefore should not be used. Discolouring, however, is primarily caused by calcium chloride. It does this by accelerating the hydration process, but yet having a retarding effect on the hydration of the ferrite compound in Portland cement. This ferrite phase normally would become lighter with hydration. However in the presence of calcium chloride, the retarded un-hydrated ferrite phase remains dark.
Concrete scaling
Concrete scaling and flaking is the loss of surface mortar. It is primarily a physical action caused by hydraulic pressure from water freezing within the concrete, and not by a chemical corrosive action. It is for this reason that it is necessary to extend the thaw/freeze cycle as long as possible. It is best NOT to use calcium chloride based ice melters, as they have the shortest thaw/freeze cycle.
Concrete spalling
Spalling is a surface defect that is deeper than scaling. Spalls tend to occur over corroded reinforcing steel due to the presence of chloride ions.
