Most crude oil and some high quality fat feedstocks contain high amounts of phosphorus and low amounts of
fatty acids. The phosphorus and fatty acids are typically removed using two known refining processes,
neutralizing and bleaching. Bleaching for color is not necessary so only a silica adsorption step is used.
Neutralizing removes the bulk of the phosphorus and fatty acids by converting them to pasty substances called
gums and soap, respectively, which are heavier than the oil or fat and easily separated. The balance of the gums
and soap in the neutralized oil or fat are removed by silica adsorption. Only a residual amount of gums and
soap remain in the dried oil or fat.
The phosphorus and fatty acid content of the discharged oil is equivalent to refined and bleached, or RB, quality.