June 21, 2017 — High pressure descale sprays are critical to the proper performance of continuous casters, roughing mills, and hot mills.  These systems run at very high volumes (over 150,000 litres per minute) and very high pressures (3,000 psi).  These sprays remove iron oxide scale particles from the surface of slabs and operate in closed loop systems consisting of collection sumps and settling tanks as well as media filters and cooling towers.

The existing chemical treatment at an integrated steel producer is leading to clogged nozzles (Figure 1) and pump impeller replacement, causing down time as well as high maintenance costs.

The inefficient removal of suspended solids from the descale water (Figure 2a & 2b), coupled with the impact that improper scale removal can have on the quality of the steel being produced, make the treatment of this water very critical.

JNE Environmental was invited to perform onsite testing of our formulations, with excellent results. We were very quickly able to demonstrate that our formulation is capable of destabilizing the iron and oil emulsion and generate a very large and stable floc (Figure 3). Using a sample of their existing filter media, we were able to simulate the filter performance and produced clear water with a TSS of 13mg/L!

We are currently discussing a production trial with this customer and look forward to reporting on its success shortly. Through proper emulsion destabilization and evaluation of their current media filter performance, we developed a potential solution that can increase the cleanliness of the descale water (82 mg/L existing vs 13 mg/L with JNE Environmental). This may allow us to decrease the media bed depth in the filters, which reduces the pressure drop across the filter. This reduction in pressure drop may allow them to recover enough flow to address the current product-driven flow limitation.