How is fire extinguisher powder made

How is fire extinguisher powder made, and what equipment is used?

June 11th, 2026

The dry chemical powder filled in fire extinguishers is produced through a process that differs between conventional dry powder and ultra‑fine dry powder, but generally follows a common four‑step procedure: raw material crushing, material mixing, drying, and screening.

Core Production Steps and Equipment

A standard production line for common dry chemical powder (e.g., ABC type) with an annual capacity of 1,000 to 25,000 tonnes typically consists of the following key equipment.

Step	Core Equipment	Function & Process Details
1. Raw material crushing	Crushing system (e.g., jet mill, ball mill, mechanical mill，raymond mill)	Crush bulk materials such as monoammonium phosphate and ammonium sulfate to the required fineness. This is a critical step for fire‑extinguishing performance. For example, a planetary ball mill operating at 400 rpm for 30 minutes can produce ultra‑fine powder with small particle size and narrow distribution.
2. Mixing & silicification	Mixing‑drying‑silicification main unit (silicification machine)	This is the integrated core step. The crushed main materials and additives are loaded into the unit, mixed, and heated. Silicone oil (e.g., hydrogen‑containing silicone oil) is atomized via a spray tank and injected to silicify the powder. This forms a hydrophobic film on particle surfaces, preventing moisture absorption and caking, thereby extending shelf life and improving fire‑extinguishing efficiency.
3. Conveying & screening	Conveyor, elevator, screening machine	The semi‑finished product from silicification is conveyed to a temporary storage bin, then passed through a screening machine. Powder meeting the fineness requirement goes to the finished product bin for packaging; oversize coarse material is returned to the crushing step for re‑processing.
4. Packaging & filling	Automatic filling line, gas charging device	After the dry powder is produced, it is filled into extinguisher cylinders. Modern lines use automatic filling lines controlled by computer programs to achieve high‑precision, high‑efficiency filling, weighing, and gas charging. A complete extinguisher production line also includes equipment for leak testing, hydrostatic testing, drying, and printing.

Common Types of Dry Chemical Powders and Formulation Examples

Different types of dry chemical powders have different formulations:

ABC dry chemical powder – The mainstream product on the market (about 48% share). It is based on monoammonium phosphate (70–75%) and ammonium sulfate (13–16%), with additives such as white carbon black and silicone oil. It can extinguish Class A (ordinary combustibles), Class B (flammable liquids), and Class C (flammable gases) fires.
BC dry chemical powder – Uses sodium bicarbonate as the main raw material. Mainly for Class B and Class C fires.
Ultra‑fine dry chemical powder – Targets a very fine particle size (e.g., >50% of particles <40 µm). The formulation is more complex; for example, one novel ultra‑fine dry powder contains alkali residue, monoammonium phosphate, sodium bicarbonate, potassium iodate, sodium oxalate, magnesium carbonate, silicone oil, etc. The smaller the particle size, the larger the specific surface area and the higher the fire‑extinguishing efficiency.

Advanced Process Direction

To further improve product performance and reduce cost, the industry is developing more advanced processes.

Supersonic jet milling, classification, and modification integrated system – Enables in‑situ modification of the powder, i.e., surface treatment during ultra‑fine grinding. This method achieves better hydrophobic and oleophobic properties and effectively reduces costs.

Practical Considerations

Environmental protection – Because dry powder particles are extremely fine, a complete dust collection system (e.g., pulse jet dust collectors) must be installed to recover dust and purify air, meeting environmental requirements.
Formulation – Specific parameters such as material proportions, silicification temperature, and duration directly determine the final product quality grade. The typical processes described above need to be rigorously adjusted according to product standards in actual production.