Case Study | CONQINPHI 20 T/H MVR Evaporative Crystallization System for Sodium Sulfate Recovery in Silica Gel Production

Project Snapshot

Background

Silica gel production via the sodium silicate acidification process generates large volumes of sodium sulfate wastewater — roughly one ton of Na₂SO₄ is produced for every ton of silica gel. Our client, a leading silica gel producer, needed to treat 20 tons per hour of dilute sulfate liquor containing residual silica fines.

The key challenge was economics at scale: at 20 T/H, a conventional steam-driven evaporation system would consume enormous amounts of live steam. The client required a solution combining remarkably low operating cost, excellent salt quality, and full water reuse — without disrupting continuous silica gel production.

The CONQINPHI Solution

CONQINPHI engineered a fully integrated MVR evaporative crystallization system, delivering decisive advantages over steam-based designs:

1. MVR Energy Recovery Core A high-efficiency centrifugal compressor recompresses the vapor generated in the evaporator, raising its temperature and pressure so it can be reused as the heating medium. This closed-loop thermal design slashes live steam consumption — the system runs primarily on electricity, delivering dramatically lower energy costs than multi-effect alternatives.

2. Anti-Scaling Forced Circulation Crystallizer Given the scaling tendency of sulfate solutions, we selected a forced circulation (FC) crystallizer with optimized circulation velocity and a refined seed-crystal operation mode, ensuring stable heat transfer and extended, uninterrupted run cycles.

3. Silica Fines Removal Pretreatment A dedicated clarification and filtration stage removes entrained silica particles from the feed, protecting the heat exchanger and guaranteeing clean, uniform crystal growth.

4. Automated Crystal Handling The system includes a continuous discharge centrifuge and dryer, producing dry, free-flowing, consistently high-quality sodium sulfate ready for packaging — plus a clean condensate line recycled back to the silica gel process.

Results & Performance

✅ Proven capacity – Stable operation at the full design capacity of 20 T/H, with automatic load adjustment to match production fluctuations.

✅ Outstanding energy efficiency – The MVR design delivers significantly lower energy consumption than conventional steam evaporators, with a notably short payback period.

✅ High-quality recovered salt – The crystallized Na₂SO₄ features excellent purity and uniform crystal size, meeting market requirements for industrial-grade applications such as detergents, glass, and chemicals — turning waste into a sellable by-product.

✅ True water circularity – The vast majority of the water is recovered as clean condensate and reused in the silica gel washing process, greatly reducing freshwater intake and discharge volume.

✅ Long cleaning cycles – Thanks to the anti-fouling design, the system operates for extended periods between CIP washes, maximizing uptime and reducing maintenance workload.

✅ Full automation – PLC-based control with real-time monitoring of density, level, vibration, and compressor performance; a single operator can supervise the entire unit with ease.

Why CONQINPHI

From pilot testing and process simulation to fabrication, installation, and commissioning, CONQINPHI provided a single-source, turnkey solution — backed by responsive after-sales support and dependable spare parts availability.

Partner With Us

Dealing with sodium sulfate or other high-salinity wastewater from chemical production? CONQINPHI designs and builds MVR evaporation and crystallization systems from pilot scale to large industrial capacities. Request a free process evaluation today.