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The distinctive properties of clays make them appropriate for all kinds of functions
This text, written by Jason Ng, Northern Alberta Institute of Technology and Andrea Sedgwick, Northern Alberta Institute of Technology, initially appeared on The Dialog and hasbeen republished right here with permission:
The invention and use of clays dates again to 30,000 years in the past, making clays one of many oldest supplies utilized in society. Clays are naturally occurring supplies that have been first used to make pottery and are actually used abundantly within the manufacturing of products, together with ceramics, cosmetics and constructing supplies. Clays additionally play an necessary function within the “terroir,” the encompasses a wine develops primarily based on the place the grapes are grown.
Clay has distinctive properties which might be helpful in industries starting from manufacturing to building. However these properties can even pose a problem in managing mine waste.
Clays and clay minerals are tiny particles with a novel plate-like construction lower than two microns in dimension (for comparability, the typical thickness of a strand of human hair is about 70 microns). The small dimension of clay minerals and their distinct construction give them distinctive properties, and various kinds of clay minerals can exhibit numerous traits.
Properties of clays
There are 4 primary teams of clay mineral: kaolinite, illite, vermiculite and smectite.
Smectite clays for instance, have the best capacity to swell, usually increasing a number of instances their preliminary quantity. Bentonite clay, a smectite, can swell as much as 18 instances its preliminary quantity by taking water into its interlayer, the space between two layers of clays. This property makes it helpful as a spill absorbent, but additionally signifies that it is rather troublesome to take away water from clay in dewatering processes, as within the case of mine waste administration.
In distinction, kaolin, or china clay, doesn’t swell and has low permeability, making it preferable for producing porcelain or enhancing the printability of paper.
Clays additionally develop plasticity when moist, giving them the power to stretch with out breaking or tearing — a important property for pottery sculpting. The drying and firing processes trigger the water molecules to flee from between the clay sheets, and irreversibly altering the chemical construction of the clays, turning the piece into a tough and long-lasting pottery piece.
Clay and wine
Winery homeowners use their data of clay content material within the soil to assist them make selections about planting and irrigation in order that they’ll enhance the standard of the wine they produce. The soil composition in vineyards influences the drainage ranges and the uptake of minerals and vitamins for the roots. Sandy soils are nice for drainage, and clays, which have a web detrimental cost, assist retain positively charged vitamins together with calcium, magnesium and potassium.
Clays additionally maintain water fairly properly, which may be useful in dry climates to maintain the soil cooler and wetter. Sure vine varieties produce one of the best leads to a specific soil kind. For instance, clay soils have a tendency to supply daring and muscular purple wines like sangiovese and merlot and white wines like chardonnay.
Clay in mine waste
Whereas clays may be priceless supplies in sure industrial processes, they’ll additionally trigger issues in mine waste administration. For instance, oilsands tailings — produced from the floor mining of oilsands — encompass a combination of water, sand, positive particles, clays and residual bitumen.
These tailings are saved in ponds, the place the heavier sands settle shortly to the underside and the positive particles and clays stay suspended. The water-loving nature of clays signifies that numerous water is trapped within the tailings, making consolidation and subsequent reclamation very difficult.
As of 2018, there are greater than 1.2 trillion litres of fluid tailings accrued in these ponds in Alberta.
This fluid tailings downside isn’t unique to oilsands as all types of mining — similar to copper, potash and diamond — produce tailings. As the worldwide manufacturing of minerals and metals proceed to rise, so does the manufacturing of tailings.
Clay measurement strategies will change into more and more necessary to observe and optimize tailings administration methods.
Therapy strategies
Many tailings therapy options modify clay properties to speed up dewatering and consolidation, and so understanding the clays current is important for any therapy strategies to work.
Clays may be characterised primarily based on particle dimension, mineral kind, floor space, cation trade capability, plasticity and stream behaviour. In a laboratory setting used within the oilsands business for many years, methylene blue dye might help decide a few of these necessary properties.
The Northern Alberta Institute of Know-how and its companions are creating an automatic clay analyzer primarily based on the methylene blue index methodology that may make it attainable for in-field clay measurement. This could optimize therapy processes, translating to value financial savings and sooner reclamation of the tailings ponds.
From serving to to create reclaimable tailings to producing a bottle of high quality wine, advances in clay measurement can convey many financial and environmental advantages.
Jason Ng, Analysis Affiliate, Oil Sands Sustainability, Northern Alberta Institute of Technology and Andrea Sedgwick, Utilized Analysis Chair, Oil Sands Sustainability, Northern Alberta Institute of Technology
This text is republished from The Conversation underneath a Inventive Commons license. Learn the original article.
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