Vermiculite is a commonly used dry, loose fill material for packaging. It provides cushioning for delicate objects to prevent impact and shock during shipping and handling. It is pourable, which allows for packing around irregularly shaped items. In addition to being used widely in packaging, its chemical and physical properties, such as its ability to absorb water, thermal insulative properties and lightweight, make it a versatile material with numerous applications across many industries, including agriculture, building and construction and waste treatment.
What is Vermiculite?
Vermiculite is a hydrated magnesium aluminum silicate mineral. While found on most continents, the largest current mined deposits are in Russia, South Africa, China and Brazil. It is a material that is mined using open cast techniques which means it is separated from other minerals and sorted using screens to provide specific particle size distributions. When processed in special furnaces, its form becomes much larger, elongated particles that are lightweight, easily compressed, highly absorbent and fireproof. This process is called exfoliation, similar to what can be achieved with clays and nano-clays. It can be processed in loose-fill form, sheets and others. In loose form, vermiculite can be classified into five categories based on weight and size and the three most common and regularly used categories are:
- Grade 4A Vermiculite – Extra coarse and non-dusty and considered to be the best grade vermiculite on the market. It can be used in combination with UN certified packaging to provide absorbent cushioning for shipments of hazardous materials that may leak or spill.
- Grade 3A or 3C Vermiculite – Smaller granule size and less expensive than Grade 4A. It has the same properties as Grade 4A but finer.
Benefits of Vermiculite Packing Material
Vermiculite packing is lightweight, which limits extra costs related to weight-based shipping rates. As previously mentioned, it is loose fill which allows for pourability around irregularly shaped objects. The converted vermiculite does not decay, break down or emit odors. It is also highly absorbent, which makes it an ideal solution to contain leakage that may occur when shipping liquids. This is especially important for specific chemicals including flammable types. With these properties, it is a commonly used material with UN-certified and DOT-approved hazmat packaging systems.
Common Uses of Vermiculite
In general, vermiculite has a wide range of uses. In addition to packaging, common applications include, insulation, fire protection, horticulture and in special coatings, among others. A few of these applications will be described in more detail below.
- Packaging – Vermiculite is used in packaging because it is lightweight, reducing shipping costs. It is also an excellent impact absorber making it ideal for fragile goods. Its flame retardant properties allow for specialty applications where ignition may be a risk. It is an inert mineral which means it can be very useful in transporting most chemicals whether they are positively- or negatively-charged or in liquid or solid form.
- Molded shapes – Exfoliated vermiculite can be mixed with sodium silicate and potassium to produce a damp mixture which is then hydraulically pressed into a shape in a mold and cured at 180oC for 24 hours. These compression-molded parts with withstand service temperatures up to 1150oC and can be used in the metal industry as insulation in various processes. These finished goods are then used in fireplaces, sound panels and high-temperature insulation.
- Agriculture – Agricultural applications use vermiculite because it expands 30 times its original size when heated. When added to soil, the thermal conductivity insulates the soil and minimizes temperature fluctuations. Additionally, it helps to create air channels and to hold air and water very efficiently. Specific applications include soilless growing media, seed germination, soil conditioner and bulb and root crop storage
- Building & Construction – In the building and construction, vermiculite is widely used mainly for its insulating properties. In roofing components, vermiculite can be added to Portland cement to decrease weight and increase insulation. Exfoliated vermiculite can be mixed with a water repellent to fill in hollow spaces and masonry and can be used in fireplaces, attics and furnaces.
- Desiccant – A desiccant is a material used to maintain dryness in closed environments such as a jar, package, or dehumidification device. They are commonly used for storing chemicals that are sensitive to moisture or when contact with water can cause violent or potentially catastrophic reactions. Vermiculite’s high absorption properties make it a very suitable material as a desiccant.
Vermiculite packaging materials provide a well-regarded, cost-effective solution for shipping delicate goods due to its cushioning capabilities. Due to its high liquid sorption properties, it is also well suited as a layer of protection for leaks and spills that may occur in transit when shipping liquid hazardous materials.