Sulphuric acid production sits at the heart of modern copper mining and smelting operations. At Codelco’s Chuquicamata complex in Chile’s Antofagasta Region, sulphuric acid plants process off-gas from the copper smelter, producing market-grade acid at a scale of over 2,000 metric tonnes per day as part of the operation’s environmental compliance programme. The infrastructure required to handle this acid output around the clock, in one of the most punishing industrial environments on earth, faces a corrosion challenge that few coating systems are built to survive.
Chuquicamata sits in the interior of the Atacama Desert, the driest non-polar desert in the world. Acid storage tanks, process piping, structural steelwork, and containment infrastructure at facilities like this are exposed simultaneously to concentrated sulphuric acid vapour, extreme daily temperature swings, intense ultraviolet radiation, and the abrasive desert conditions that define mining operations across Chile’s copper belt. It is precisely this combination of acidic exposure and harsh climate that has driven mining operations toward RTV silicone coatings as a long-term alternative to traditional epoxy and vinyl ester systems.
TSS, the exclusive Sub-Saharan Africa distributor for CSL Silicones, supplies SI-COAT 579 CM for exactly these conditions — acid storage infrastructure, process equipment, and structural steel in Southern Africa’s own copper and acid-handling operations.
Why Sulphuric Acid Tanks Punish Conventional Coatings
Sulphuric acid storage and process infrastructure presents one of the most aggressive corrosion environments in industrial mining. Concentrated acid vapour attacks coating films chemically, while the structural steel beneath is simultaneously stressed by thermal cycling as tanks fill, empty, and respond to ambient temperature swings that can exceed 30 degrees Celsius in a single day in desert mining regions.
Traditional epoxy and vinyl ester coatings are formulated to resist chemical attack, but they share a structural weakness: rigidity. As acid tanks and associated steelwork expand and contract with temperature and process cycling, rigid coatings crack at the molecular level long before any visible failure appears. Acid vapour and moisture penetrate those microscopic cracks, and corrosion begins beneath the coating surface, hidden from inspection until blistering or delamination eventually exposes the damage.
In copper mining regions such as northern Chile, where smelting and acid production operate continuously and infrastructure cannot be taken offline for extended recoating campaigns, this failure mode creates a difficult maintenance cycle. Acid plant shutdowns are expensive, and surface preparation for traditional recoating — typically requiring abrasive blasting to remove failed coating and expose clean steel — is both costly and operationally disruptive on live acid infrastructure.
The Case for Silicone Coatings in Acid Service
RTV silicone coatings such as SI-COAT 579 CM are formulated specifically to address the failure mode that limits traditional acid-resistant coatings. As an elastomeric coating, silicone flexes with the substrate rather than cracking under thermal stress, maintaining a continuous protective film through the daily and seasonal temperature cycling that defines desert mining environments.
SI-COAT 579 CM is applied as a single coat directly to the substrate, without the multi-layer build-up required by traditional epoxy systems. This single-coat approach reduces application time significantly on large acid storage and process infrastructure, an important consideration when minimising plant downtime is a priority for continuous-process operations such as acid plants.
The coating’s resistance to sulphuric acid and other acidic process chemicals makes it suitable for tank exteriors, structural support steelwork, piping systems, and containment infrastructure surrounding acid handling equipment. Its adhesion to tightly bound rust and existing coatings also means that ageing acid infrastructure can often be recoated without the extensive abrasive blasting that traditional systems demand — a meaningful advantage on live process equipment where full shutdown for surface preparation is operationally difficult to schedule.
What This Means for Southern Africa’s Mining and Acid-Handling Sector
Southern Africa’s mining and minerals processing sector includes substantial sulphuric acid production and handling infrastructure, much of it supporting copper, gold, and base metal operations across South Africa, Zambia, and the broader region. The corrosion challenges documented at major international operations like Chuquicamata are not unique to Chile — they are the same fundamental chemistry and thermal stress conditions found wherever sulphuric acid is produced, stored, or handled at industrial scale.
Southern African operations face their own combination of intense UV exposure, seasonal temperature variation, and in some regions, coastal salt exposure layered on top of acid process chemistry. A coating system proven to withstand sulphuric acid exposure in one of the world’s harshest desert mining environments offers a relevant benchmark for what Southern African acid infrastructure requires.
TSS works with mining operations, smelters, and acid-handling facilities across South Africa, Zambia, Tanzania, Namibia, and the wider region to specify SI-COAT 579 CM for tank exteriors, structural steel, and process infrastructure exposed to acidic service conditions.
Frequently Asked Questions
Is SI-COAT 579 CM suitable for sulphuric acid tank exteriors?
Yes. SI-COAT 579 CM is formulated to resist sulphuric acid and other acidic process chemicals commonly encountered in mining and minerals processing environments. It is applied to tank exteriors, structural steelwork, and surrounding infrastructure rather than acid-wetted interior surfaces, which require specialised lining systems.
How does SI-COAT 579 CM compare to epoxy coatings in acid service?
Epoxy coatings are rigid and prone to cracking under the thermal cycling common in acid plant environments. SI-COAT 579 CM is elastomeric, flexing with substrate movement rather than cracking, which prevents the corrosion creep that develops beneath failed epoxy films over time.
Does SI-COAT 579 CM require sandblasting before application on acid infrastructure?
In most cases, no. SI-COAT 579 CM adheres well to tightly bound rust and existing coatings, allowing surface preparation by pressure washing or solvent wipe-down rather than full abrasive blasting, which reduces downtime on live process infrastructure.
Is SI-COAT 579 CM available for mining and acid-handling operations in Southern Africa?
Yes. TSS is the exclusive Sub-Saharan Africa distributor for CSL Silicones and supplies SI-COAT 579 CM to mining, smelting, and acid-handling operations across South Africa and the broader Southern African region.
Long-Term Protection for Acid Infrastructure
Sulphuric acid production and handling infrastructure operates under some of the most demanding corrosion conditions in industrial mining. The combination of chemical exposure, thermal cycling, and harsh climate that defines operations like Chuquicamata in Chile’s Atacama Desert is mirrored in mining and minerals processing facilities across Southern Africa.
SI-COAT 579 CM offers a proven, single-coat alternative to traditional acid-resistant coatings, built to withstand the chemical and thermal demands of acid service infrastructure without the recurring failure cycle that limits conventional systems.
To discuss SI-COAT 579 CM for your acid-handling or mining infrastructure, contact us through our contact us page or visit our FAQ page for more information. Proud distributors of CSL Silicones.
- Image used is not from the case study, purely for reference.