Yellow phosphorus (YP) has been commercially produced since the 1920s. First in the USA by the
Tennessee Valley Authority (TVA), next in Russian (Kazakhstan) in the 1950s, and finally in China
in the late 1970s and early 1980s. There are operations in Vietnam and Sarawak on a smaller scale.
YP has become very in vogue due to its use in the production of lithium iron phosphate battery
cathode precursor materials by the Chinese and other western battery manufacturers. The YP is
also used to produce purified phosphoric acid and higher grades of acid using a thermal oxidation
process after smelting.
This paper will look at the basics of the smelting including slag chemistry, alloy chemistry and offgas
chemistry. The paper will look at the design of the furnaces used in the YP production process
as well as the downstream recovery of phosphorus from the smelter off-gas stream to YP.
The next part of the discussion will focus on the operations of a YP smelter with regards to control
of the furnace to optimise phosphorus recovery to YP. Will discuss tapping cycles for alloy and slag
with a view to optimal phosphorus recovery.
The discussion will close out with a review of operational challenges in the smelter and a brief
description of the downstream conversion of YP to high purity phosphoric acid.