What Particle Sizes Are Ferox ZVI Products Available In?

Particle size is one of the most important specifications in zero valent iron selection: it determines how the iron can be delivered, how far it travels in the subsurface, how fast it reacts, and how long it lasts. Hepure’s Ferox line is micron-scale ZVI engineered in several grades, each matched to a delivery method.

Ferox products by particle size and application

• Ferox PRB — granular ZVI with a uniform 20/60 mesh size, engineered for permeable reactive barriers and soil mixing. Free of rust, dust, and lubricating oils for consistent reactivity and hydraulic performance.
• Ferox Flow — a fine, highly reactive ZVI powder designed for injection into and down-gradient of contaminant source zones, with particle sizing chosen for distribution through the formation.
• Ferox Target — a fine, fast-reacting ZVI powder for targeted injection into source areas and high-concentration zones.
• Ferox Plus (eZVI) — micro-scale ZVI delivered in an emulsified vegetable oil formulation, combining iron reduction with a long-lasting electron donor in one injectable product.

How ZVI particle size is measured

Two methods are standard, and they answer slightly different questions:

Fisher Sub-Sieve Sizer (FSSS) uses air permeability through a packed sample — combined with material density (7.86 kg/dm3 for iron) and the resulting pressure changes — to calculate an average particle size based on surface area. It yields a single representative number for a powder.

Laser diffraction particle size analysis measures light scattered by particles and produces a full particle size distribution (PSD) curve, typically reported at the 10th (d10), 50th (d50), and 90th (d90) percentiles. This shows not just the average but the spread — useful for predicting injectability and transport, since the coarsest fraction often controls behavior in the formation.

When comparing ZVI products, make sure you’re comparing the same measurement type: an FSSS average and a laser-diffraction d50 for the same powder can differ, and the d90 tells you what the largest particles look like.

Which grade for your project?

As a rule of thumb: granular Ferox PRB for reactive barriers and soil mixing; fine powders (Flow, Target) for direct-push or well injection; Ferox Plus where you want combined chemical reduction and anaerobic bioremediation from a single injection.

Detailed specification sheets for each grade are available from our technical team — call 866-727-4776 or request more information, and see the Zero Valent Iron product line for full details.