That sand is one of the most important materials in the modern world is no overstatement. In fact, it is the second largest natural resource by volume after water and accounts for the largest volume of solid material extracted globally.
In a one-on-one with Quarrying Africa, Ruchin Garg, regional manager, Middle East & Africa at CDE, says the world is on track to be a planet of nearly 10-billion people by 2050. In addition, about 70% of the world’s population will live in urban areas by 2050. Shifting consumption patterns, growing populations, increasing urbanisation and infrastructure development have accelerated the demand for sand three-fold over the last two decades. The world now needs 50-billion tonnes per year (tpy), an average of 18 kg per person per day.
Yet, according to some forecasts, buildable sand may run out as early as the first half of this century. According to a United Nations report, the world has been exceeding easily available sand resources at a growing rate for decades, spending the sand ‘budget’ faster than the sand that can be produced responsibly.
Sand has traditionally been obtained from natural sources such as rivers and coastlines. However, new regulations have been enacted to protect these sources. In many cases, sourcing sand from riverbanks and shorelines has been outlawed completely because of the dire environmental consequences such as erosion in rivers and coastlines, as well as changes in the water’s PH levels. Consequently, notes Garg, illegal sand extraction has in fact become a major transactional crime, just behind drug trafficking and counterfeiting.
As the scarcity of natural sand becomes a reality, the industry has been forced to adopt a suitable and sustainable alternative fine aggregate. Manufactured sand has therefore proven to be the most economical and ecological alternative. Yet, wet processing, a crucial part of sand production, has its own challenges due to the documented global water shortages.
“Water is indispensable. Essential for life, water is vital for economies and climate regulation. It is of utmost importance, therefore, that our water resources be protected – even regulated. The mining, quarrying, manufacturing and construction sectors accounted for 10,6% of total water use in Europe in 2017 and the industry compounds water scarcity, water efficiency and wastewater management challenges the world over. All corners of the globe are facing unique challenges,” says Garg.
Tech to the rescue
Continued innovations in wet processing technology are helping the industry meet the rising demand for manufactured sand, while using water sparingly, thus overcoming water management challenges.
While laws governing water vary around the world, Garg says it is a resource that is absolutely essential to the extractive industries and is therefore increasingly under the water management microscope.
“Innovations in the washing sector and the continued advancement of CDE’s pioneering wet processing solutions are, however, supporting quarry operators and materials processors alike in order to overcome the challenges stemming from water management – cost-based, efficient, sustainable and regulatory,” says Garg.
CDE consistently invests in research and development with the aim of enhancing the capabilities of its premier water recycling and management equipment. At the forefront of its water recycling systems is the AquaCycle™ thickener, a single, compact and user-friendly unit that can be applied to high and low tonnages across many markets.
Delivering competitive advantages to its customers, CDE’s AquaCycle™ thickener accelerates return on investment by maximising production efficiency, minimising the loss of valuable fines and reducing water and energy costs.
An alternative to water extraction and the costly process of pumping water to the plant, CDE’s AquaCycle™ thickener is a highly efficient water management solution that minimises costly water consumption by ensuring up to 90% of the process water is recycled for immediate recirculation.
“In the past, it was not possible to turn the fine crushing waste into a quality product, as the technology at the time did not offer the precision needed to produce a reliable and homogeneous artificial sand from the fine crushing waste,” says Garg. “Such technology was realised in the new CDE Combo™ – a complete solution to both the ever-increasing demand for fine minerals and the ever-decreasing use of natural resources.”
The CDE Combo can be moved around, making it ideal for quarry fines. It can process spoil at one location and then be moved to another. Additional important advantages of the Combo unit are the integrated water supply and recirculation systems.
Benefits abound
Though water recycling may seem simple in theory, it is, in practice, much more complex. Water thickeners are not born equal and their efficiency is the result of years of dedicated research, development and refinement. Every aspect of the CDE design is carefully considered so that the system is responsive to the site-specific needs.
“All CDE equipment is designed to allow plug-and-play operation, it is pre-wired and pre-tested before despatch, designed for rapid assembly and set up and can start processing material within days of arrival on site. These design considerations and factory acceptance tests significantly reduce installation time and accelerate return on investment,” says Garg.
Return on investment with a CDE AquaCycle™ thickener is typically achieved in just six to nine months.
CDE’s modular wet processing equipment can contribute to the easing of water scarcity issues arising from the materials processing industry’s consumption of water resources, greatly improve water efficiency and better wastewater management practices.
“Developing technological solutions to tackle these mounting challenges is paramount for many materials processors seeking to boost the profitability of their operations by minimising the consumption of costly water resources,” he says.
Case studies
Over the years, CDE technology has been deployed on several African sites with great success. The partnership between CDE Global and Estim Construction in Dar es Salaam was a particularly exciting breakthrough in the African market.
Estim Construction’s dedication to excellence and innovation mirrors the CDE work ethos, so developing the most efficient sand washing solution was a gratifying process resulting in a product that surpassed Estim Construction’s expectations.
To ensure that Estim Construction had complete ownership of its operation, a CDE engineer trained an Estim Construction operator to oversee the installation and take actions based on the changing characteristics of the feed material. The plant is fed 50 tonnes per hour (tph) to produce 40 tph of final quality washed sand. Waste and water from the EvoWash report to the AquaCycle high-rate thickener so that up to 90% of the water is recycled and reused. The concentrated fines are flushed out, resulting in minimal water to replenish the water tanks.
Founded in 2011, Mission Point Mining (MPM) is now a major player in the South African sand production industry and employs 30 people on its mining site in Sasolburg. “Since we replaced our bucket wheel with a CDE turnkey plant, we have witnessed a significant increase in the quality of our product and a no less significant decrease in our water consumption, so switching to CDE technology has proven to be the smart choice. With the EvoWash and Aquacycle working in tandem, the quality of our washed product is much better and much drier than any other producers’ in the region,” says MPM’s Johann Pretorius.
Since MPM switched to the CDE cyclone and water recycling technology, demand for its products has grown to the point that the company is now expanding its business and exploring the best value for money solutions to increase sand production.
The future
According to Garg, water management systems are becoming a must-have for mine and quarry operations to comply with environmental regulations. Matters concerning the protection of finite resources on the planet will only become more prevalent, too.
“At CDE we see the solution increasingly pointing towards manufactured sand – it is in more demand as natural sand sources deplete, there is value in quarry waste/fines and it is predicted that the use of manufactured sand by the construction market will overtake the use of natural sand by 2026,” concludes Garg.
