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Differences of K type and S type Aerosol Compound

April 5, 2020

K type aerosol compound is short for “Potassium Nitrate Based Aerosol” and S type aerosol compound is short for “Strontium Nitrate Based Aerosol”.
When people talking about the difference of K type and S type aerosol, the main difference between them is because of main oxidant, S type with main oxidant of strontium nitrate and K type with main oxidant of potassium nitrate, other components and accessories similar or almost the same, so the main difference between “K” and “S” type aerosol is their main oxidant chemical of potassium nitrate and strontium nitrate, below we are showing these two chemicals:


Chemical and Specifications

Potassium nitrate is chemical name, its molecular formula is KNO3, CAS number is 7757-79-1 and UN number is 1486.

Mainly Specifications is normally industrial grade and agricultural grade GB/T1918-1998, for better understand of specifications we listed in the following table:

Inspection ItemsUnitIndustrial GradeAgricultural Grade
Purity% Min99.897.5
Moisture% Max0.10
Chloride (as CI-)% Max0.01-0.030.8
Sulphate (as SO4 2-)% Max0.01
Insoluble matter in water% Max0.01
Fe% Max0.003
Hygroscopicity% Max0.25
K 2 O% Ma45.4
Nitrogen (in nitrate)% Min13.5


Potassium nitrate is with characteristics of colorless and transparent rhomboidal crystals and/or white powder, its relative density is 2.109 and melting point is at about 334°C. it decomposes at 400°C and turns into potassium nitrite releasing oxygen, and then in continuous heat turns into burnt potash; it is highly soluble in water, liquid ammonia and glycerin but insoluble in anhydrous alcohol and ethyl ether.
But is not deliquesce n the air, as strong oxidizer, it will burn and explode when meeting with organics releasing irritant gas, and if mixed with carbon power or sulfur, it also burns with strong light.


It is normally being packed in plastic woven bag or paper bag inner with plastic bag in 20, 25, 50, 500 and 1000 kilo grams net.


Any operators should wear protective smock including respirator and mask and rubber gloves etc, be careful not to inhale the powder of potassium nitrate to protect respiration apparatus.

Handling and Storage

When we handle and store the potassium nitrate, we should:
store it in a cool, ventilated and dry warehouse, away from moisture, heat or kindling, furthermore, avoid mixing with organic compound or sulphur or reducer during storage and transportation in case of explosion. And also protect the material from the sun and rain during transportation, most importantly, carefully load and unload in case of any crash.


  • TV Kine-scope glass, glass refining agent and motor light glass.
  • compound fertilizer and foliar spray fertilizer for crop and flower.
  • Fireworks to produce purple flame and black power in mining, ignition wire and firecracker.
  • Drugs as penicillin potassium salt in medicine industry and catalyzer, ceramic and enamel.
  • Main oxidant as fire extinguishing agent in fire protection industry, such as K type aerosol, Representative companies are Stat-X, Firepro, Dynameco, Pyrogen, DSPA etc.
  • Salt bath of heat treatment, cigarette paper, concentrating agent, conservatives in salted meat and chromogen in food industry and so on.


Chemical and Specification 

Molecular formula of strontium nitrate is Sr(NO3)2 with CAS number of 10042-76-9 and UN number of 15075.1/PG3, its EINECS is: 233-131-9.

Mainly specifications as per GB/T669-1994:

ItemQuality Index
High ClassFirst ClassQualified Class
Purity99.3% Min99.0 % Min98.0% Min
Moisture0.05% Max0.1% Max0.5% Max
Calcium (Fe)0.05% Max0.1% Max0.5% Max
Iron (Fe)0.005% Max0.001% Max0.05% Max
Barium (Ba)0.05% Max0.1% Max0.5% Max
Water insoluble0.1% Max0.2% Max0.5% Max
Sodium (Na)0.1% Max0.2% Max0.5% Max


It is white crystal and power. The relative molecular weight is 211.63 and its density is 2.986. It is not deliquescent in the air and can dissolve in water and liquid ammonia, but not in ethanol and nitric acid.
The melting point is 570°C, it will decompose under high temperature. It has the strong oxidizing property and can cause burning and explosion while meet the open fire it put it together with organic substance and sulfur, it gives out the carmine flame while burning.


It is packed in 20, 25, 50, 500 and 1000 of plastic woven bag or as per the buyer’s requirement.

Protection and Handling and Storage

Almost the same as potassium nitrate, see protection, handling and storage methods of potassium nitrate.


It is mainly used to produce fireworks, signal flare, flame tube, match, TV kine-scope, analysis agent, optical glass, medicine, as well as fire suppression agent like what is S type aerosol fire extinguishing device design and research out from china.


  • This product shall be stored in the place where keep ventilation and dry against rain, heated and isolation under sunlight.
  • This product shall not be delivered or stored together with organic inflammable substance.

To analysis and describe above chemical properties of strontium nitrate and potassium nitrate, we can see both of them can apply in fire suppression systems as an main aerosol oxidant.
For apply in fire suppression purpose they main differences are:

  • Potassium nitrate aerosol ( K type aerosol) a bit high in fire extinguishing ability, its design density is 50-100 gram per cubic meter, in anther words, to cover one cubic meter space only need 50 grams at most 100 grams of k type aerosol agent; and k type is with design density of 100 gram per cubic meter, to cover one cubic meter space need 100 gram s type aerosol, in china s type aerosol design density is: 100 grams per cubic meter.
  • K type aerosol is cause more residue when discharging and have corrosion to instruments equipment and machines, but s type aerosol is only have little residue and have no corrosion to instrument equipment and machines. This is why S type aerosol is belongs to generation III aerosol and people think better than K type aerosol.

Now in worldwide we call for new energy , such as new energy automobiles, new energy power, new energy electronics, new energy technology etc, the world’s development theme now is new energy, people need more clean and green energy, so absolutely now s type aerosol is much more popular than k type aerosol in fire suppression fields.

We used to produce k type aerosol 10 years ago but now we are make effort to research and development s type aerosol, because the s type aerosol is the market direction in the future, for this product we already leading the market now.

More details are available:

  • Catalogue, Brochure, Flyer.
  • Installation Manual.
  • Material Data Sheet.
  • IP67 Water Proof and Dust Proof Test Report.
  • Certificates and Approvals.

Except accessories, all the aerosol system we have is based on S type aerosol forming agent.


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