The invention relates to a modification method of an
ammonium sulfate solid in the
semiconductor industry, which comprises the following steps: (1)
winnowing the
ammonium sulfate solid in the
semiconductor industry to obtain
ammonium sulfate particles and volatile impurities; and (2) mixing the
ammonium sulfate particles with a
carboxylic acid crystal modifier, and then carrying out
vacuum drying to obtain the
crystal-transformed
ammonium sulfate. According to the modification method provided by the invention, through
winnowing, the
ammonium sulfate solid is in a fluidized state, and volatile impurities are taken out along with gas, so that subsequent adsorption through
activated carbon is facilitated; purified ammonium sulfate particles are mixed with a
carboxylic acid crystal modifier to induce the
crystal growth direction of ammonium sulfate to change, so that an original orthorhombic
system is converted into a cubic
system with higher stability, and the
surface energy and hygroscopicity are reduced; the
sodium content of the finally obtained
crystal transformation ammonium sulfate is less than or equal to 0.05 wt%, the heavy
metal content is less than or equal to 2ppm, the volatile
impurity content is less than or equal to 0.005%, the crystal form is a
cubic crystal system, the critical
relative humidity at 25 DEG C is more than or equal to 85%, and no obvious deliquescence and
caking exist after the
crystal transformation ammonium sulfate is placed for 30 days.