Project Overview

Location: Hoopstad, Free State
Industry: Fertilizer storage and handling
Environment: High pH, corrosive internal atmosphere
Product used: Si‑COAT 579 CM
Application date: January 2025

The Problem

Due to the high pH content of fertilizer stored in the building, the internal steel structure required continuous maintenance to combat corrosion and degradation. Previous maintenance measures had not provided long‑term corrosion control.

Site Conditions and Constraints

The facility remained operational during the evaluation period. Full shutdown or replacement of the steel structure was not feasible, and any coating solution had to perform under continuous exposure to fertilizer material and corrosive conditions.

Technical Approach

A trial application of Si‑COAT 579 CM was carried out on selected structural columns to assess corrosion maintenance performance under real operating conditions. Surface preparation focused on removing loose corrosion prior to coating, without the use of a primer.

Monitoring and Observations

After three months, localised discolouration was observed at the base of certain columns. A follow‑up investigation was conducted to determine the cause of this discolouration.

Investigation Findings

The discolouration was identified as corrosion runoff from areas above the coated section, collecting at the base of the columns and in rough steel areas affected by historic corrosion. The coating itself remained intact, and the discolouration was easily removed with a damp cloth.

Additional Application Area – Hopper Structure

The hopper structure showed advanced corrosion and was identified as a high‑risk area. Parts of the hopper had already been primed with red oxide prior to the introduction of Si‑COAT 579 CM. Areas prepared without primer demonstrated that the coating could be applied directly to prepared steel without primer, with no corrosion observed after three months.

Outcome

Areas coated with Si‑COAT 579 CM showed no active corrosion after three months under the same exposure conditions. The trial confirmed the suitability of the coating for corrosion maintenance in high pH fertilizer environments.

Key Takeaways

Surface discolouration does not automatically indicate coating failure.
Primer is not required for corrosion maintenance when surface preparation is adequate.
Real‑world monitoring is critical for validating coating performance.