While metal containers are reactive, they are a crucial element to any factory. The typical laboratory houses a considerable range of chemicals that require safe storage. As we mentioned in our earlier discussion about why chemicals are stored in plastic containers, every substance has unique properties and storage requirements.
Strong acids, for example, are best stored in PMP or HDPE containers. This is partly because these plastics are chemically inert and so won’t react with the substance. Metal containers, on the other hand, are significantly more chemically reactive than other materials like plastic or glass. For this reason, it is not suitable to store certain chemicals in metal containers as they are likely to corrode.
But if metal containers are so reactive, why do laboratories use them at all?
Flammable Solvent Cabinets
Flammable solvents include substances like alcohols, toluene, and hexane. These chemicals are liquids that have a flashpoint of approximately 37.8°C. This is the lowest temperature at which the flammable liquid releases enough vapour to ignite.
The vapour released by flammable solvents lingers above the liquid. This represents the main source of danger as vapour is prone to ignition by naked flames, or sparks produced by electrical switches such as thermostats.
Fire resistant metal cabinets are ideal for the storage of flammable solvents. This is because they have at least 30 minutes of fire resistance, and are robust enough to withstand any damage. Metal cabinets are also equipped with metal trays to contain spillages.
In this way, fire resistant metal containers are ideal for flammable solvents as they protect them against naked flames. This is something plastic or glass containers could not facilitate.
Naked flames and sparks in the workplace aren’t the only things metal containers protect against. Chlorinated solvents, such as chloroform, would have violent reactions with flammable solvents if the two were mixed. This is why chlorinated and flammable solvents should be kept separate.
While chlorinated solvents like trichloroethylene (TCE) do not have flashpoints, meaning that they are highly resistant to ignition, they do have flammable limits in air. These limits are measured in volume percent, and define the concentration of solvent vapours in the air under which a flame may occur. TCE, for example, has a flammable limit of 8% at 25°C.
While these concentrations are rare, they become more likely when solvents are stored in confined areas. Therefore, chlorinated solvents should be stored in well ventilated metal containers, cabinets, or bins to avoid ignition.
Reactivity of Metal Containers
As we have seen, metal containers are vital for storing different kinds of solvents. However, they do have certain drawbacks. Metal containers are not able to store most acids because of how they react together. You can see the general word equation for this reaction below:
Acid + Metal → Salts + Hydrogen Gas
When metal reacts with acid, salt and hydrogen gas are produced. This ultimately reduces the volume of the chemical being contained. As well as this, acid is a highly corrosive substance with the ability to eat away at most materials.
When acids and bases are stored in Teflon containers, for example, corrosion isn’t a problem because of the hydrophobic properties of PTFE. Since metal containers don’t have this slippery advantage, it means that they are more likely to corrode when storing particular chemicals.
Not all hope is lost for metal containers, though, as they provide excellent protection for the transportation of chemicals. At ReAgent, our 1000L IBCs (Intermediate Bulk Containers) are protected by an exterior metal cage; and our 200L drums give you the option of a stainless steel outer-skin for maximised protection.
Finding the right container for your product is like finding the right case for your phone. There are many characteristics that have to be considered: Is it shatterproof? Does it provide enough protection? Is it the right size and shape?
Luckily, at ReAgent we specialise in manufacturing and packaging a variety of chemicals so that we can meet the individual needs of your business. From HDPE bottles to 25,000L tankers, we’ve got the perfect packaging for you, whether it’s for corrosive acids, flammable liquids, or even deionised water.