ANFO vs Emulsion

ANFO is dry ammonium nitrate prill mixed with fuel oil. It is poured or blown. Emulsion is a water-in-oil ammonium nitrate matrix. It is a fluid. That is the split. Only the emulsion side is a pumping job.

NAPCO does not manufacture ANFO, emulsion, or blasting agents. We build the stainless rotary gear pumps that move unsensitized bulk matrix, AN solution, and high-emulsion blends between tanks, silos, and loading trucks. See explosives and mining for the industry page.

If you came here to pick a blasting agent, talk to your explosives supplier. If you came here because a plant or truck has to move one of these products, stay long enough to get the handling right.

Straight ANFO

Straight ANFO is porous ammonium nitrate prill plus about 6% fuel oil. It is dry. It flows like grain. It has no water resistance.

It is cheap, and it is still the default on a dry hole when the rock wants heave more than shock.

You do not pump it. You pour it or blow it. See pumping ammonium nitrate emulsion and ANFO: straight ANFO stays on augers or compressed air, never on a gear pump.

The liquid on an ANFO pad is usually the fuel oil that coats the prill. That circuit is petroleum transfer, not ammonium nitrate transfer. See gear pumps for fuel and petroleum.

Emulsion

A bulk emulsion is concentrated ammonium nitrate solution dispersed in a fuel-oil phase. An emulsifier holds the interface. The matrix looks more like grease than like a thin liquid.

Until it is sensitized, unsensitized matrix is typically handled as an oxidizer, not as a Class 1 explosive. Bulk emulsion products lists that state as UN3375, Class 5.1. Sensitization (gassing at the hole, or microballoons in packaged product) is what turns it into a blasting agent.

That is why mines run bulk emulsion on wet ground, and why a plant has a real pumping job. The matrix is a fluid. It has to move tank to tank, silo to truck, truck to reload.

Packaged / cartridge emulsion is the other emulsion form. It is plant-sensitized and loaded by hand. It is not pumped. That page is cartridge emulsion explosives.

Heavy ANFO sits in the middle

Heavy ANFO is emulsion matrix blended with ANFO prill. The usual range is 20% to 70% emulsion by weight.

Adding emulsion coats the prill, raises density, and starts to give the column water resistance. Adding more emulsion improves those traits and raises cost. High-emulsion mixes can still move through a gear pump. High-prill mixes are augered.

Do not spec a pump off the name. Spec it off the blend and the product TDS.

Site-mixed emulsion and repumpable matrix are logistics variants of the emulsion side, not a third blasting agent. Details live on bulk emulsion products.

What you can pump

Three searches get mixed together. The handling is not interchangeable.

Straight ANFO: dry prill plus fuel oil. Augered or blown. Never pumped.

Cartridge emulsion: packaged, plant-sensitized. Hand loaded. No transfer pump.

Bulk emulsion matrix, hot AN solution, and high-emulsion Heavy ANFO: fluids. Stainless gear pump, surface transfer, low shaft speed.

Stay on stainless. Ammonium nitrate attacks iron. Live product copy and the emulsion guides put this duty on the S models only. Comparison: stainless steel vs ductile iron pumps.

Shear matters. The emulsifier holds the oil-water interface. High-speed impellers tear it. Gear pumps move a fixed volume between teeth at low shaft speed. Working principle: rotary gear pump working principle.

NAPCO pumps are surface transfer: tank to tank, plant to truck, silo to reload. Not borehole injection of already-gassed product. That high-pressure loading job is progressive cavity duty. See gear pumps vs progressive cavity pumps.

Selection logic for the bulk side: pump selection for emulsion explosives and gear pumps for bulk emulsion trucks.

Which stainless pump, if the product is a fluid

Specs below are from the live product pages, Rev. 07/2026. Water tables. Higher-viscosity fluids may require lower RPM. Do not invent an ANFO flow rate. There isn’t one.

PA300S

The PA300S is the 3-inch stainless pump. 158 GPM at 280 RPM and 10 PSI. 140 GPM at 100 PSI. 13.4 brake HP at 100 PSI. Max 100 PSI, max 280 RPM, 173 lbs. 3-inch NPT.

Plant pump-over, truck loading, high-volume matrix transfer.

The live page names sensitized explosive bulk emulsion among the fluids this pump handles. That is still surface transfer. It is not a license to charge a hole with a gear pump.

PA200S

The PA200S is the 2-inch stainless pump. 69 GPM at 190 RPM and 10 PSI. 60 GPM at 100 PSI. 5.7 brake HP at 100 PSI. Max 100 PSI, max 190 RPM, 114 lbs. 2-inch NPT.

Skids, smaller batch plants, auxiliary circuits where the 3-inch pump is oversized.

The live page lists bulk emulsion among typical applications.

Both sizes prime themselves and run either direction. Nitrile gears are standard. Viton gears are the option for hot AN solution or aggressive formulations. Viton seals are already on every NAPCO pump. Gear choice: nitrile vs Viton gears.

Rebuild

A factory kit is gears, seals, bearings, and gaskets. 2 to 5 hours on the 3-inch (PK300S). 2 to 4 hours on the 2-inch (PK200S). Hand tools. The product pages put kit cost at 30 to 50 percent of a new pump.

Jobs this page is not

• Selling ANFO, emulsion, packaged boosters, or detonators.
• Specifying a pump to move dry prill.
• High-pressure downhole loading of gassed product.
• Specifying anything but stainless on an ammonium nitrate circuit.

If you still need to size flow and pressure from viscosity, use how to size a rotary gear pump.

FAQ