Read the full article from Vince Beiser titled "why the world is running out of sand", here.
Our Dad Washes Dirt!
When my children are asked what their father does for a living they raise their eyebrows and reply, “our dad washes dirt”.
Concrete, asphalt, glass and a myriad of consumable products used in everyday life need sand in their production process. This sand needs to be washed to meet the specifications needed in this manufacturing process.
Let’s look at concrete, made from gravel, cement sand and water. Our changing, ever-growing world uses billions of tons of this necessary building product every year. To produce concrete sand, the sand must meet a specific gradation to conform with the other components in the concrete making process.
Sand Washing in North America
We have been washing sand in North America for many generations and doing so in many ways.
Traditionally sand has been washed by the means of moving sand in slurry form up an incline. This process has the water travelling backwards while the sand moves forwards. The fine particles of silt and clay travel backwards with water, therefore, washing the silt and clay from the sand. This process is known as washing through a sand screw.
Twenty years ago, if you visited a sand and gravel pit in North America, about 90% of them would have used a sand screw in combination with a wet sizing screen box, producing washed gravel and sending the sand in a slurry to the screw.
This works well if you have a course sand with a low silt and clay content.
In these pits, you would also have found a classifying tank which would have been used to remove larger content of silt and clay, or sand with too many fines in the belly of the sand.
As more of these pits started running out of bank run sand, easily mined, they had to add dredges to mine sand below water. The classifying tank helped manage large volumes of water being sent by the dredge.
The simple screen and sand screw plants now became large stick-built structures towering into the air to accommodate the classifier needing height to gravity feed the rest of the plant.
These large structures became difficult and costly to maintain due to height and tight spaces to work in.
The water removed with the silt and clay had to be sent to a series of settling ponds that needed constant maintenance. The sand screw wasn’t always efficient and good sand would get washed to the settling ponds wasting hundreds of thousands of tons of usable sand, an inefficiency costing producers millions of dollars of lost revenue.
The Cyclone Solution
The antidote to these cumbersome fixed structures is cyclone technology to produce washed sand. This cyclone cut accurately at the 200-mesh removing only the silt and clay and leaving valuable sand in the product.
Natural sand is a finite resource, and the industry here in the US is wakening up to the sustainability agenda, climate change and growing demands like I’ve never seen before in my 20+ years’ experience.
The drive is no longer just about commercial gains (whilst still important). The industry now appreciates regulatory measures and the need to ensure operations are as sustainable and eco-friendly as possible. Producers have shifted from the short-term gains to the long-term vision and want a partner who can help them achieve this.
That’s why they’re talking to CDE!
Customized Washing Solutions
In a small town in Northern Ireland, CDE Global was producing innovative cyclone plants which were being installed across the world. CDE saw a need in the market for a pre-wired, pre-plumbed wash plant that could be delivered from the factory, built and commissioned in a matter of weeks at the customer's site. These wash plants were producing aggregate materials to the customer's exact production requirements and specifications.
These modular wash plants would be a customized plant meeting each individual producer’s needs.
CDE had the technology in place, hoppers and conveying systems, wash boxes, cyclones dewatering screens, heavy-duty logwashers, upward flow classification, attrition cells, and water management.
All this technology could all be implemented in low profile modular plants.
Natural sand and gravel, manufactured sands, recycled materials, mine tailing reclamation and speciality sands could be processed accurately at the desired production levels the customer required.
CDE in North America
CDE USA entered the North American market in 2013 and has consistently delivered innovative modular wash plants to the market place in this short time.
Traditional reserves of material are dwindling, and new sources are being utilized. CDE has the knowledge and experience to service the North American market with its innovative washing technologies.
As the industry generations change, the new generations are hungry for advances from the older classifier, sand screw way of doing things to the advanced cyclone dewatering screen technologies. There is a change in the air and CDE is leading the way in this new washing, water management revolution.
The Combo™ X900
Discover the next generation Combo™: the X900 by visiting Andrew and the CDE team at ConExpo. This revolutionary sand washing plant provides five processes on one single chassis, combining sand washing and water treatment on one, eco-friendly, portable solution.