Slack Wax DAO (Deasphalting Oil)

About This Product

Slack Wax DAO comes from the heavy end of lubricating oil refining. Vacuum residue is treated with a light hydrocarbon solvent such as propane or butane to remove the asphaltenes, leaving a high-molecular-weight deasphalted oil, and the wax crystallised from that oil is DAO slack wax (CAS No. 64742-61-6). It is the heaviest and most complex of the LMO, SPO, MMO and DAO grades, and higher molecular weight aromatic and naphthenic compounds give it a dark amber to light brown colour, 5.0 maximum on the ASTM D-1500 scale. Solvent deasphalting was developed in the 1930s and 1940s to recover base oil components from vacuum residue; the wax was first handled as a by-product before refiners began selling it alongside the lighter grades. DAO melts at 69–74°C, the highest in the series, with an oil content of 5–20% and carbon numbers in the C20–C50 range, giving it the greatest hardness and structural integrity of the four. Its viscosity of 18.5–22.5 cSt at 100°C is around five times that of LMO, so pumping, heating and downstream processing need to be planned for a much heavier material. Dark as it is, DAO is a strategically important raw material: it is one of the main feedstocks for microcrystalline wax, the refined product used in pharmaceuticals, food coatings, cosmetics and precision applications. Direct industrial uses include heavy rubber and tyre compounds, construction waterproofing membranes and damp-proofing, pipeline and anti-corrosion wax coatings, bitumen and road asphalt modification, moisture barriers for heavy-duty corrugated board, electrical cable insulation and jacketing compounds, and industrial adhesives and sealants. Packing options are 20–22 MT flexitanks, ISO tank containers, 190 kg steel drums and bulk tanker loads.