As winter wraps up, it’s important for snow and ice management companies and municipalities to plan for storing ice-melting supplies. As a leading supplier of ice melt chemicals, we’ve developed this comprehensive guide to handling and storing calcium chloride and other ice melt products.
To effectively manage and store both liquid and dry calcium chloride, the first step is to grasp the significance of five key product attributes that strongly influence recommended practices:
- Hygroscopic Nature: Calcium chloride exhibits hygroscopic properties, allowing it to absorb moisture from the air. This characteristic can lead to clumping and caking in dry calcium chloride products like pellets, flakes, and briquettes.
- Deliquescent Feature: Solid calcium chloride products have a deliquescent nature, enabling them to absorb sufficient moisture from the air to transform into a liquid state.
- Exothermic Heat of Solution: Solid calcium chloride products release a significant amount of heat when dissolved in water due to their exothermic heat of solution.
- Corrosion Risk: The presence of chlorides in calcium chloride, in conjunction with water and oxygen, is associated with the accelerated corrosion of common metals such as steel, copper, and brass.
- Electrically Conductive Brines: Calcium chloride brines possess electrical conductivity, posing a risk of electric shock if energized electrical equipment is handled with wet hands or fabric gloves soaked in brine.
Personnel must be well-versed in the contents of the product’s Material Safety Data Sheet (MSDS) and adhere to the guidelines outlined therein. End users bear the responsibility of ensuring full compliance with federal, state, provincial, and local requirements governing the handling and storage of calcium chloride. This comprehensive understanding of product attributes is essential for maintaining safety, preventing risks, and ensuring regulatory compliance throughout the handling and storage processes.
Handling and Storing Calcium Chloride Packaged Products
Solid calcium chloride products are available in various packaging types designed to cater to different needs. These include bags, boxes, pails, drums, and Flexible Intermediate Bulk Containers (FIBCs).
- Bags: Constructed from plastic or multilayered paper with a moisture barrier, bags feature either a valve-type* or heat-seal closure.
- Boxes: Comprising cardboard with a plastic liner, boxes are sealed using a twist tie.
- Pails: Made of heavy-duty plastic, pails come with snap-on lids.
- Drums: Standard 50-gallon steel drums have a removable top secured with a clamping ring.
- FIBCs: Characterized by a woven polymer exterior, a plastic liner, and a bottom spout for unloading.
Packaged products are typically delivered on wooden pallets, often covered with a plastic shroud or stretch-wrapped. The available package types, sizes, and pallet configurations may vary by product.
Packaged Product Handling: Products are transported via flatbed truck, enclosed van, intermodal container, or boxcar. Pallets on flatbed trucks should be fully covered with tarps to maintain cleanliness and packaging integrity during transit. Forklifts or pallet jacks are required to lift and move full pallets. Pallets are usually four-way, except for those carrying FIBCs or drums, which are two-way only.
Product inventory management should follow a first-in, first-out basis to minimize quality issues stemming from moisture absorption over time. Damaged bags should be mended and used ahead of others.
Packaged Product Storage: Palletized products covered by an intact plastic shroud may be stored outdoors on a well-drained asphalt or concrete surface. If the shroud is torn, pierced, or removed, storing the palletized product indoors or under a waterproof tarp is recommended. Products in boxes, drums, or FIBCs, typically not shrouded, should be stored indoors or under a waterproof tarp. Palletized pails, stretch-wrapped but not shrouded, can be stored outdoors due to their watertight nature.
Full pallets of bags, pails, boxes, or drums can be stacked with specific configurations, while FIBCs are typically stacked two high and two wide. Individual packages should be stored indoors in a dry area. Bags with a valve-type closure should lie flat to maintain a seal, and any partially used opened package must be tightly resealed to prevent exposure to humid air, avoiding caking and liquid brine formation.
Handling and Storage of Bulk Solid Calcium Chloride
Bulk shipments of solid calcium chloride, totaling approximately 90 tons, are facilitated through hopper cars and hopper trucks of varying capacities. The handling and storage of bulk solid calcium chloride involve several crucial considerations.
Bulk Solid Handling: Various methods, including drag chains, screw conveyors, pneumatic conveyors, bucket elevators, and belt conveyors, are employed for the unloading and transportation of bulk solid calcium chloride. The effectiveness of handling equipment is paramount, emphasizing mechanical reliability while minimizing potential detriments from attrition, exposure to humid air, and dust emissions. Materials like hot-dipped, galvanized, and stainless steels have proven effective for solids-handling equipment, with stainless steels being unsuitable for handling hot bulk solids (>100°F [>38°C]) due to susceptibility to chloride stress cracking at elevated temperatures.
Bulk Solid Storage: To prevent caking and clumping in storage, the hopper design should minimize product exposure to humid air. Hopper configuration is crucial for maintaining a uniform particle-size distribution, with poorly designed hoppers causing sifting during filling. Well-designed “mass flow” hoppers ensure uniform particle distribution. Carbon steel with an internal epoxy-based lining and an exterior epoxy-based paint is preferred for large hoppers, while stainless steel resistant to stress cracking is effective for smaller surge hoppers. Nonmetallic materials like fiberglass and common plastics are corrosion-resistant but may face structural integrity issues if exposed to heat release during the washing of solids.
Transporting, Handling, and Storing Liquid Calcium Chloride
Liquid calcium chloride in bulk is offered in concentrations ranging from 28 percent to 42 percent by weight. Delivery is typically facilitated through tank trucks or tank cars. The specific configurations of transportation equipment and unloading stations depend on individual cases. While a general overview of important considerations is presented below, it remains the responsibility of the end user to formulate detailed procedures that ensure safety, efficacy, and full compliance with applicable regulations tailored to their particular situation.
Bulk Liquid Handling: Managing bulk liquid calcium chloride becomes more complex with increasing concentrations due to the rising crystallization temperature (freeze point) of the solution. In colder ambient temperatures below the freezing point, it is imperative to design handling equipment that either maintains the product’s warmth through insulation and heat tracing or allows for complete drainage when the equipment is out of service. This necessitates the incorporation of features such as sloped lines and drains at low points in the system. Freezing points for a few typical concentrations are provided below.
| CaCl2 Concentration | 32% | 35% | 38% | 42% |
| Freezing pt. °F | -17°F | +20°F | +48°F | +69°F |
| Freezing pt. °C | -27°C | -7°C | +9°C | +21°C |
Tank trucks and tank cars transporting calcium chloride solutions typically undergo unloading through a bottom outlet using a fixed pump, facilitating the transfer of the solution to a storage tank. The connection between the unloading pump and the outlet valve is commonly established using a thick-walled, flexible hose. The design of the unloading system is contingent upon factors such as the desired unloading time, distance to storage, elevation change, and available utilities.
Proper venting of both the sending and receiving tanks during liquid transfer is essential to prevent potential tank rupture or collapse. For tank trucks or tank cars, it is advised to have the vent valve open AND the manway propped open, but caution must be exercised to avoid attempting to open the manway cover if the tank is under pressure.
Tank trucks and tank cars are typically equipped with both internal and external valves on the outlet. If difficulty arises in turning either valve, it may be frozen in place due to crystallized calcium chloride. Attempting to force open a frozen valve can result in equipment damage. In the event of suspected crystallization, the application of steam or warm air on the exterior of the piping is recommended to melt the frozen product and facilitate valve movement.
Air pressure can be an alternative to a pump for unloading from either the bottom or top outlets, depending on the presence of an internal dip pipe. The air supply should be regulated at a maximum of 50 psig or below the pressure rating of the tank and its relief device, whichever is lower. After unloading is complete, the air pressure in the tank will drop, accompanied by the sound of air rushing through the unloading line. All pressure must be vented from the tank truck or tank car before releasing it for return transit.
Insulated tank trucks and tank cars, equipped with steam coils for heating the product before off-loading, require careful handling to prevent equipment damage. Precautions include gradually increasing coil pressure, maintaining maximum steam pressure below 150 psig, ensuring the calcium chloride solution temperature remains well below 170°F (77°C), shutting off steam to the coils after unloading a quarter of the solution, blowing steam coils empty after use to prevent freezing of residual water during winter transit, and avoiding attempts to increase product temperature by blowing steam directly into the liquid.
Bulk Liquid Storage: Storing bulk liquid calcium chloride can be achieved using open-top or closed tanks. Open-top tanks are typically employed for large outdoor vessels where dilution from precipitation and exposure to humid air is either negligible or managed through mixing or reconcentration of the calcium chloride. Closed storage tanks with limited air exchange offer the advantage of maintaining a uniform concentration over extended periods without additional mixing. If periodic mixing is required, it is usually achieved through pumped recirculation or mechanical agitation. Although air sparging is an option, it has the potential to impact product concentration by introducing or removing water and creating calcium carbonate precipitate through the reaction between calcium chloride and carbon dioxide in the air.
Tank design should include features that facilitate the cleaning of solids from the tank’s bottom, which may originate from various sources:
- Sodium chloride precipitation as liquid calcium chloride cools.
- Carbonate and sulfate present in dilution water that precipitates upon contact with calcium.
- Carbonate precipitation when calcium chloride reacts with carbon dioxide in the air.
For large liquid storage tanks, the preferred construction material is carbon steel with an epoxy-based interior lining and epoxy-based exterior paint. Common stainless steels are not suitable for liquid calcium chloride storage due to the risk of chloride stress cracking, even at temperatures as low as 100°F (38°C). Nonmetallic materials like fiberglass or plastic are effective for smaller tanks at near-ambient temperatures; however, their puncture resistance and structural strength relative to carbon steel should be carefully evaluated.
Releasing the Empty Calcium Chloride Take Truck or Tank Car for Return Transit
Releasing an insulated tank truck or tank car that has undergone bottom off-loading with steam coils involves specific steps, which apply to various situations where valves must be closed and manways secured before the vehicle is released for return transit. Follow these guidelines:
- Close the internal bottom outlet valve.
- Close the external bottom outlet valve, carefully disconnect the unloading line, and securely replace the bottom external outlet valve plug.
- Disconnect the steam lines and use compressed air to blow out the heating coils. Do not replace the caps on the inlet- and outlet-steam connections; allow them to hang by their chains.
- If steam has been applied to the steam jacket of the bottom outlet leg, refrain from replacing the caps after disconnecting the steam line to prevent freezing and cracking of the bottom outlet leg. Allow the caps to hang by their chains.
- After removing all connections, replace the closures on all other tank openings and securely fasten the dome cover.
Summary
In conclusion, ensuring the safe handling and storage of calcium chloride products is facilitated when the handler comprehends the reasons behind the need for distinct procedures and recognizes the variations based on specific situations. While it is crucial to adhere to these general guidelines when dealing with calcium chloride, they should not be viewed as an exhaustive technical reference. Additionally, it is advisable to consult product and application literature, including Material Safety Data Sheets, for comprehensive information on health and handling precautions, safety guidelines, and the regulatory status of the product.
If you have questions, need additional information, or are ready to get a quote on ordering any calcium chloride or other ice melt products, please contact our team today! We are open 24/7 for pick-up in Maryland or for delivery nationwide.