Beneficial trends and technological advancements in the mining industry are being introduced regardless of the depressed market conditions that the sector faces, says environmental management company I-CAT Environmental Solutions tech- nical manager Morne van Wyk.

One such trend is recycling water for reuse in processes, a viable alternative to pure treatment and discharge, he says, adding that water has become a scarce and expensive commodity for industries, and environmental compliance with regulations, such as those under water-use licences, is enforced stringently.

Van Wyk asserts that mechani- cal evaporation systems, which ensure the effective and environmentally safe reduction of excess wastewater in the mining industry, have moved to the forefront of water management solutions in recent years.

Several mechanical evaporators are currently available and offer different results, depending on their size and configuration, Van Wyk notes.

The organisation has had much interest from the mining market, as mechanical evaporators offer a cost-effective, short-term solution for effectively managing excess wastewater.

“We do not believe in using or adding chemicals to wastewater to purify it or get it to discharge standard. We provide only mechanical purification systems, despite numerous challenges at some clients’ projects. However, our excellent technical and design team is focused on innovation and providing solutions for challenging projects,” he says.

Other technological advancements I-CAT highlights are ultrafiltration (UF) and nano- filtration membranes, which “have come a long way” since first being introduced to the industry, with significant ongoing research and development having been invested in this technology.

He explains that the key bene- fits of Singapore-based water treatment specialist Hyflux’s Hyflux Kristal hollow-fibre ultrafiltration membrane, which is distributed by I-CAT, includes reinforced polyethersulfone material with a high tensile strength, improved hydrophi- licity readily absorbing or dissolving in water, low fouling and an asymmetric membrane structure with a high flux rate, as well as a consistent high-quality permeate with a sharp rejection profile and a long membrane life span.

The Azud filtration systems and its water treatment solutions also offer a range of products, with the automatic disc and screen filtration used for prefiltration, the major features of the range.

Besides the commodities price slump, the mining industry also has to deal with the mineral demands of an ever-growing global population, the loss of essential maintenance and management skills, and a lack of environmental and resources management.

“We use a combination of technologies to provide our clients with the best and most cost- effective solutions, while maintaining consistent awareness of the environment, energy and social demand,” he states, adding that the company’s self- cleaning, low-maintenance solutions do not require recurring chemical costs.

Van Wyk highlights that I-CAT has been awarded several contracts by mining groups to monitor, manage and recycle water, adding that its technology is considered “world-leading, affordable and effective”, as it has developed solutions to clean process water where many older technologies and processes have failed.

Performance Assessments, Mechanical Evaporation Systems
Van Wyk asserts that four fundamental assessments greatly influence I-CAT’s ability to perform efficiently and should, therefore, always be carefully considered as part of a financial study.

He states that the first is the appropriate air to water ratio (2000:1), adding that I-CAT ensures that no less than 2 000 ℓ of ambient air is discharged at a high velocity with every 1 ℓ of water atomised. This ratio is critical to achieve the maxi- mum percentage evaporation of water pumped into the air, ensuring the column of air does not become dense to the point that it resembles a sprinkler.

Van Wyk adds that two experimental studies have been conducted on the relationship between water supply, air supply and evaporation efficiency, asserting that the information of the two studies were extra- polated to derive a logarithmic relationship between air-to-water ratios and normalised evaporation, which showed that there is a rapid increase in the evaporation rate with increased air-to-water ratio.

The second assessment is water droplet particle size. Van Wyk says a water drop falling through air or floating in air is subject to evaporation and will decrease in size. Therefore, this makes it essential to produce the finest water droplet particle to increase evaporation and kilowatt efficiency.

He further highlights that a third assessment, the evaporation process, which involves extracting heat energy from the accelerated and compressed incoming ambient air to vaporise the water contained in the fine mist, is fundamental. The high velocity stream of compressed air thus accelerates the shredding process of the atomised particle.

The fourth principle involves a 3.2 mm orifice water fracturing nozzle design which, Van Wyk asserts, has proven critical to ensure minimal downtime, owing to nozzle blockages, while achieving the finest possible droplet size.