Abstract: Technology process for preparation of feed grade zinc oxide with by-product zinc oxide mud from formaldehyde sulphoxylate production was studied.Process includes pulping,purifying,filtering,washing,drying,and calcining.Influences of purifying conditions,calcining temperature,and time on product quality were emphatically investigated.Results showed the best process conditions were as follows:adopting deionized water to make pulp,using H₂O₂ solution with mass fraction of 27.5% to remove tiny formaldehyde sulphoxylate,employing zinc powder to replace heavy metals,then taking sodium sulfide as precipitator to eliminate the remained trace heavy metals,and controlling the calcining temperature at 900 ℃ and calcining time for 4 h.Under those conditions the purity of the obtained feed grade zinc oxide reached 99.5% and its quality has met the first grade requirement in Standard of HG/T 2792—1996.

Key words: zinc oxide mud, purifying, calcining, feed grade zinc oxide