The invention relates to the technical field of valuable
metal recovery, in particular to a method for extracting
tin from
tin slag. The method comprises the following steps: firstly, dry-mixing the
tin slag with NaOH and KOH, then carrying out ball milling, then adding
sodium nitrate into the mixture in a
mass ratio of the tin
slag to the
sodium nitrate of 1: (0.02-0.03) for multiple times, mixing, reacting at 400-600 DEG C for 1-4 hours, and cooling to
room temperature after the reaction is completed, so as to obtain
molten slag; the
molten slag is crushed into
powder, the
powder and water are mixed and leached, the mixture reacts for 1-3 h at the temperature of 40-60 DEG C, tin-containing
leachate is obtained after
solid-liquid separation, and the
leaching rate of tin in the tin slag is larger than or equal to 90%. According to the method,
sodium hydroxide and
sodium nitrate are adopted as a mixed
solvent, tin is preferentially converted into soluble
sodium stannate, compared with a traditional acid leaching method, the corrosivity is lower, compared with a traditional alkali melting method, the reaction is more sufficient, compared with a pyrogenic
smelting method, the
energy consumption is reduced by adopting a medium-temperature reaction, the technological process is short, and the efficiency is high.