Industrial Press Release

BASF: Making It Better
Canadian General-Tower

By definition, a desert imposes extreme climatic conditions that can destroy even the most robust structures. But when these structures are intended to contain a corrosive solution and they're made of a material that's little thicker than a credit card, the challenges are amplified dramatically. In such cases, the success of the structures comes down to the use of the right chemistry.

The Customer

Headquartered in Cambridge, Ontario, Canadian General-Tower (CGT) is a manufacturer of coated fabrics and films. Its materials are found in pool liners, roofing, decking and containment pond liners. It also produces upholstery and soft trim products found in 85% of cars and light trucks made in North America. With a corporate lineage extending back to 1860, CGT entered the flexible polyvinyl chloride (PVC) market roughly 60 years ago.

The Challenge

To the casual observer, Salar de Atacama (Salar), the expansive salt flat in Chile near the border with Bolivia and Argentina, is an unlikely place to seek commercial success. But beneath the Salar's desert surface are large reservoirs of brine, the remains of an ancient sea, which are rich in dissolved salts of valuable lithium and potassium. Lithium is an important component of pharmaceuticals and the rechargeable batteries found in most electronics, while potassium is essential for the production of fertilizer.

At an elevation of 2,130 metres, the Salar is one of the driest places on earth and an exceptionally windy and hot one. Inhospitable though it is, these traits make the recovery of lithium and potassium more viable here than elsewhere. While many commercially significant salts are precipitated from brine in other locations, the process typically requires large amounts of heat to drive the evaporation process. But at the Salar site, brine pumped to the surface readily evaporates when exposed to sun, wind and low humidity, leaving behind crystallized salts for harvest and further processing.

While the Salar poses a unique opportunity, it also poses a unique challenge. Once the brine is pumped to the surface, it must be contained in lined ponds. Here, even small pinholes in the liner (or “geomembrane”) can allow the brine to leach back into the ground, dramatically undermining mineral-recovery efficiency, a problem that is magnified by the year-long evaporation cycle. The challenge is that the extreme conditions of constant sun, heat and wind, along with the highly corrosive nature of the brine, put extraordinary demands on the geomembrane. What's more, the liners are in near-continuous use and must withstand the weight of the large industrial vehicles used in salt harvest.

The First Steps

Because even small pinholes can cost time, energy and money, PVC was an obvious material for the liner. PVC is durable and is resistant to pinholes in both manufacture and ongoing use. The material's high elongation ensures that it drapes over any imperfections in the excavated desert surface beneath the liner, further minimizing the risk of holes. The flexibility of PVC is one of the advantages of this chemistry over other polymer systems such as high density polyethylene, and also contributes to easier installation. For its Salar site, the Chilean mining company which CGT was working with relied on CGT to formulate the rolled PVC for the project. Getting the formulation right was critical for the success of this project. “There's a lot of variation between the demands of each project and the PVC it requires,” says Tom Letourneau, Market Manager for Construction and Containment Products at CGT. “So every formulation is pretty much customized - there isn't one magic bullet.” PVC, in its simplest form, is a rigid plastic. It's through the addition of a plasticizer that the PVC gains its flexibility and its resistance to degradation. One of the key challenges is finding the right plasticizer to create a polymer with the right characteristics for the job. And with literally hundreds of plasticizers from which to choose, it's no small challenge. That's where BASF comes in.

The Solution

BASF is more than just a chemical source for CGT. “Yes, BASF is a supplier in a conventional sense,” says Letourneau. “But they also supply ongoing technical support to our team. This isn't just project- based support. They're always introducing new products in the market. And we discuss relevant projects with them.”
Part of these ongoing discussions led to the selection of Palatinol© DPHP, a new BASF plasticizer, for the project. It provided the required chemical resilience with the appropriate physical properties to fulfill the requirements.
“The last thing anyone wants is to go into a project like this and have a mechanical failure that we didn't foresee,” says emanuel Ausch, Corporate Technical Manager, Industrial Products for CGT.
“We rely on BASF for their expertise in plasticizers,” Ausch says. “We have specialized applications - extreme temperatures, chemical resistance, the need for extraordinary flexibility, for instance - where we count on BASF's chemistry, input and follow-up.”

The Implementation

CGT provided rolls of the 0.75 millimetre thick custom-formulated PVC to its fabrication partner, Montreal-based Solmax International Inc. Solmax seamed the rolls into 10 metre wide by 300 metre long panels, which were shipped to Chile. Solmax completed the fabrication on site, seaming the panels into pond liners that were one kilometre long and 300 metres wide. The installation was fast, with an average of 30,000 square metres of PVC installed and tested per day.

The Results

The finished ponds are the largest PVC geomembrane installation in the world, with nearly 18,000,000 square metres of PVC installed to date. According to Solmax, the installation is visible from the orbiting space shuttle. The ponds have been in service since 1998, when the first ones were installed using Palatinol© 711P. They remain an integral part of the operations of the Chilean mining company, which is now the world's largest supplier of lithium, accounting for 35% of the global supply.

BASF is more than just a chemical source for CGT.

“Yes, BASF is a supplier in a conventional sense,” says Letourneau. “But they also supply ongoing technical support to our team. This isn't just project-based support.,”
TOM LETOURNEAU Canadian General-Tower

BASF
100 Milverton drive, 5th Floor
Mississauga, on L5r 4H1
1-866-485-BASF (2273)
www.basf.ca

The industry:
Petrochemicals

The challenge:
Create a durable plastic film to line gigantic ponds exposed to extreme salinity and climate

The solution:
A flexible PVC liner produced with the help of a BASF product and expertise helps make a Chilean company the world's leading producer of lithium

CGT HOMECGT AUTOMOTIVECGT INDUSTRIAL

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