From making wine to managing mine waste, clay is important for many industries

The invention and use of clays dates again to 30,000 years ago, making clays one of many oldest supplies utilized in society. Clays are naturally occurring supplies that had 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 important role in the “terroir,” the features a wine develops based on where the grapes are grown.

Clay has distinctive properties which might be helpful in industries starting from manufacturing to building. However these properties may also pose a problem in managing mine waste.

Clays and clay minerals are tiny particles with a novel plate-like structure less 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 several types of clay minerals can exhibit various traits.

Properties of clays

There are four main groups of clay mineral: kaolinite, illite, vermiculite and smectite.

Smectite clays for instance, have the best potential to swell, typically increasing a number of instances their preliminary quantity. Bentonite clay, a smectite, can swell up to 18 times its initial volume by taking water into its interlayer, the gap between two layers of clays. This property makes it helpful as a spill absorbent, but in addition 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 improving the printability of paper.

Clays additionally develop plasticity when moist, giving them the flexibility to stretch with out breaking or tearing — a essential 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 information 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 internet destructive cost, assist retain positively charged nutrients including calcium, magnesium and potassium.

Clays additionally maintain water fairly effectively, which will be useful in dry climates to maintain the soil cooler and wetter. Sure vine varieties produce one of the best leads to a selected soil kind. For instance, clay soils have a tendency to provide bold and muscular red wines like sangiovese and merlot and white wines like chardonnay.

Clay in mine waste

Whereas clays will be useful 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 — include a mix of water, sand, fantastic particles, clays and residual bitumen.

These tailings are saved in ponds, the place the heavier sands settle shortly to the underside and the fantastic particles and clays stay suspended. The water-loving nature of clays signifies that quite a lot of water is trapped within the tailings, making consolidation and subsequent reclamation very difficult.

As of 2018, there are more than 1.2 trillion litres of fluid tailings collected in these ponds in Alberta.

This fluid tailings drawback isn’t unique to oilsands as all types of mining — corresponding to copper, potash and diamond — produce tailings. Because the global production of minerals and metals continue to rise, so does the manufacturing of tailings.

Clay measurement strategies will turn out to be more and more necessary to observe and optimize tailings administration methods.

Remedy strategies

Many tailings therapy options modify clay properties to speed up dewatering and consolidation, and so understanding the clays current is essential for any therapy strategies to work.

Clays will be characterised based mostly on particle size, mineral type, surface area, cation exchange capacity, plasticity and flow behaviour. In a laboratory setting used in the oilsands industry for decades, methylene blue dye may also help decide a few of these necessary properties.

The Northern Alberta Institute of Know-how and its companions are creating an automated clay analyzer based mostly on the methylene blue index method that will make it potential for in-field clay measurement. This may optimize therapy processes, translating to value financial savings and quicker 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.