The invention belongs to the technical field of
copper smelting flux, and particularly relates to a
sodium borate-
calcium-based composite flux, a preparation method and application of the
sodium borate-
calcium-based composite flux in
copper fire refining. The
sodium borate-
calcium-based composite flux is composed of
calcium carbonate, sodium borate,
sodium carbonate and
fluorite according to a specific proportion, and through the calcium-
boron-sodium ternary synergistic effect,
arsenic and
antimony are efficiently removed, and meanwhile the yield of
copper is increased. And the chemical
erosion to the
magnesite-chrome
brick of the
anode furnace is obviously reduced.
Calcium oxide generated by high-temperature
decomposition of
calcium carbonate in the flux reacts with
arsenic and
antimony to generate stable
calcium arsenate,
sodium arsenate, calcium
antimonate and
sodium antimonate, so that efficient removal of
arsenic and
antimony is realized; b2O3 generated by
decomposition of sodium borate and MgO in the
magnesite-chrome
brick form a high-melting-point Mg3B2O6
protection layer, the
erosion rate of the
magnesite-chrome
brick is subjected to breakthrough control, the
order of magnitude is reduced compared with a traditional process, and the
melt viscosity is reduced through
fluorite so as to promote
slag-copper separation. The flux can completely replace a traditional
sodium carbonate process, equipment transformation is not needed, the flux is suitable for crude copper containing high arsenic and antimony, the service life of a furnace lining is remarkably prolonged, and the copper grade is improved.