Wax is a collective name for a series of natural or artificial recovered substances. The crystalline waxes with a paraffin base recovered from crude oil are now the most important. They result from the production of lubricating oil, where they are looked upon as an unwanted contaminant. Regarded by the refineries as a waste product, the so-called slack waxes find ready acceptance in the wax industry.

Slack Wax is produced during the production of Group I base oil. During production of Group I base oil, the feedstock firstly has to go through solvent extraction process to remove aromatics and the resultant product is called raffinate. The raffinate is then diluted with solvent like methyl-ethyl ketone (MEK) to lower its viscosity to improve low-temperature filterability. The diluted oil is then chilled to -10°C to -20°C. Wax crystals will form, precipitate and removed by filtration. The removed wax becomes Slack Wax.Slack wax is the crude wax produced by chilling and solvent filter-pressing wax distillate. It serves as feedstock and that is further refined and blended to create value-added petroleum wax products.


Slack waxes are minimally refined high oil products with the range from 55°C to 65°C in melting point and oil content ranges from 3.0% to as much as 11%.

Lab Test on Slack Wax to Check Quality

Characteristic Test Method
Kinematic Viscosity @ 100 oC ASTM D-445
Oil Content ASTM D-721
Density @ 15.6  oC ASTM D-4052
Flash Point ASTM D-92
Color @ 70  oC ASTM D-150
Congealing Point 0 oC ASTM D-938
Heavy Slack Wax 2 to 12%
Heavy Slack Wax 2 to 12%
Characteristic Test Method Result
Grade H-05 H-08 H-10 H-12
Kinematic Viscosity @ 100 oC ASTM D-445 5.5-7.5 5.5-7.5 5.5-7.5 5.5-7.5
Oil Content ASTM D-721 2-5 5-8 8-10 10-12
Density @ 15.6 oC ASTM D-4052 810-840 810-840 810-840 810-840
Flash Point ASTM D-92 240 240 240 240
Color @ 70 oC (max) ASTM D-150 3 3 3 3
Congealing Point 0 oC (min) ASTM D-938 60 60 60 60

Heavy Slack Wax 7 to 11%
Heavy Slack Wax 7 to 11%
Characteristic Test Method Value
Kinematic Viscosity @ 100 oC ˚C ASTM D445 6 – 7.5
Oil Content (%wt) ASTM D721 7 – 11
Melting Point ASTM D87 56 – 65
Color ASTM D1500 1.5

Heavy Slack Wax 3 to 8%
Heavy Slack Wax 3 to 8%
Characteristic Test Method Value
Kinematic Viscosity @ 100 oC ˚C ASTM D445 3 – 6
Oil Content (%wt) ASTM D721 3 – 8
Melting Point ASTM D87 55 – 60
Color ASTM D1500 0.5 – 3


  • Bulk
  • Iso tank
  • 195 kg steel drum
  • Jumbo bag

Types Of Slack Wax

Depending on the lubricating oil fraction feedstock heavy or light grade, by product which is slack wax. We categorize them in light and heavy grade. In each category depending on the degree of refinement, they can have various oil contents range from 4 to 40 percent.

Applications of Slack Wax

Slack waxes are widely used in the production of wax emulsions, candles, polishers, construction board, matches, inks, briquettes, chalky paper, tent-cloth coating, composite wood fiber panels, rust protective products, and moisture vapor barriers

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