Expertise
Acid protection
Phosphoric acid does not corrode concrete: it dissolves it. There is no universal product here — every acid, at every concentration and every temperature, has its own answer.
The field where mistakes are not forgiven
This is the most demanding discipline in construction chemistry, and the one where we began: the revamping of the phosphoric acid lines at Maroc Phosphore, Safi, in 2002.
The difficulty is not finding an acid-resistant product. It is finding the one that resists your acid, at your concentration, at your temperature — and that holds at the interface, where the acid always eventually finds its way in.
A standard epoxy performs well against dilute acids and alkalis. It fails against concentrated sulphuric acid. A novolac vinyl ester withstands oxidising acids, solvents and elevated temperatures — it is the system for tanks, channels and chemical production floors. Acid-brick lining — ceramic tiles bedded in furan or epoxy mortar over a bituminous membrane — remains the ultimate solution for pits subject to permanent spillage: the ceramic is chemically inert, and the underlying membrane stops whatever passes through the joints.
A rule learned at Jorf Lasfar: acid never attacks the surface. It attacks joints, corners and interfaces. A flawless lining in the field, with a poorly detailed channel upstand, fails within eighteen months.
Method
How we specify
The chemical survey
Exact nature of the agent, concentration, service temperature, peak temperature, contact time, wet-dry cycling, presence of solvents or oxidisers. Without this data, no choice is serious.
System selection
Epoxy, bisphenol vinyl ester, novolac vinyl ester, furan, ceramic brick lining, rubber lining. Prices vary by a factor of five — over-specifying is expensive, under-specifying is more so.
Substrate preparation
Blast-cleaning back to sound concrete. Already-attacked concrete must be broken out until an alkaline, cohesive substrate is reached, then reinstated with a chemically compatible mortar.
Detailing
Channels, upstands, joints, penetrations, corners. These receive reinforced treatment: glass-veil reinforced laminate, coving, overlaps. This is where service life is decided.
Verification
Wet-film thickness, pull-off adhesion, porosity detection by high-voltage holiday testing. A 1 mm² defect is all the acid needs to reach the concrete.
When to call us
The environments we protect
- Phosphate and fertiliser industry — phosphoric and sulphuric acid
- Acid storage bunds and containment areas
- Channels and pits in chemical production
- Buried hydrocarbon and solvent tanks
- Wastewater treatment plants — H₂S attack
- Food processing — organic, lactic and citric acids
- Surface treatment and electroplating
- Industrial washing and pickling areas
Track record
Where we come from
Projects delivered by Jawad Izallalen under the PROJET-TS name, or in the course of his successive roles at SPTS, BASF and ADROC.
- Revamping of the 4 phosphoric acid lines at Maroc Phosphore I, Safi — acid-resistant epoxy mortars
- Refurbishment of the crystallisers at Maroc Phosphore II — rubber lining and acid-brick lining
- Maroc Phosphore III-IV, Jorf Lasfar — protection of grinding structures
- DAP units at Jorf Lasfar
- Buried hydrocarbon tanks, Total — vinyl ester laminate
- Lining of 3 km of phosphogypsum discharge pipeline
Frequently asked
What we are asked most often
Is an epoxy lining enough against phosphoric acid?
It depends entirely on concentration and temperature. Cold and dilute, a filled epoxy can be adequate. Hot and concentrated — the real case in a production unit — it requires a novolac vinyl ester, or an acid-brick system. The answer comes from your service data, not from a catalogue.
Why is ceramic brick lining still used, despite the cost?
Because nothing replaces it in a pit subject to permanent spillage. Ceramic is inert: it does not age chemically. The complete system — membrane, resistant mortar, tiles — provides two successive barriers. It is expensive, it is slow, and it lasts thirty years.
Can you work without shutting the unit down?
Rarely, for this type of protection: resins require a dry, clean, ventilated substrate. What matters is the preparation of the shutdown. We are used to working within the planned shutdown windows of the phosphate industry — every day counts, and it is organised weeks ahead.
How do I know my existing lining is at end of life?
Blistering, chalking, colour change, debonding at the joints, and above all exposed aggregate. Holiday testing reveals porosity invisible to the eye. Better a year too early than a month too late: once the acid reaches the concrete, the cost multiplies.
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