1.1 This standard describes a method for determining sulfated ash in new lubricating oils containing additives and in additive concentrates intended to be added to mineral oils. These additives usually contain certain metals such as barium, calcium, magnesium, zinc, potassium, sodium, tin. They can form combinations with one or more of the following elements: sulfur, phosphorus, chlorine. 1.2 Sulfated ash can be used to indicate the concentration of known organometallic additives in new oils. Barium, calcium, magnesium, potassium and sodium are transformed into their respective sulfates and tin (stannic) into oxide. Sulfur and chlorine have no influence, while phosphorus, if present in concentrations of more than 0.1%, can modify the results by remaining partially in the ashes. Note 1 - As zinc sulfate tends to decompose slowly into zinc oxide at the combustion temperature prescribed in the method, zinc-containing veins may lead to variable results due to conversion. incomplete zi.nc sulfate oxide, Note 2 - This method is not applicable to lubricating oils containing lead or to used engine oils. It is also not recommended for the analysis of lubricating oils not containing additives; for such oils, use the NBN T 52-119 method,
NBN T 52-120-1955 history
1977NBN T 52-120-1955 Petroleum products - Sulfated ash from lubricating oils and additives