饲料级湿法磷酸脱除硫酸根技术研究

Research on SO_4^(2-) removal in feed grade wet-process phosphoric acid

饲料级湿法磷酸中硫酸根的含量会影响饲料级磷酸钙盐的品质及物理特性。以磷精矿为脱硫剂,研究了不同磷酸浓度下脱硫剂用量、反应温度、反应时间对磷酸脱硫效果的影响,为生产合格的饲料级磷酸提供技术参考。研究结果表明:以稀磷酸(五氧化二磷质量分数为25.13%)和浓磷酸(五氧化二磷质量分数为48.56%)为研究对象,以磷精矿粉为脱硫剂,可以有效脱出湿法磷酸中的硫酸根;控制反应时间为3 h时,对于稀磷酸和浓磷酸,当脱硫剂用量分别为磷酸的5%和8%时,脱硫反应基本完成,脱硫率可达到80%以上;当脱硫时间为3 h时,反应温度对稀磷酸的脱硫效果影响不大,但对于浓磷酸则反应温度宜控制在50℃以上。

The content of sulfate ion in feed grade wet-process phosphoric acid is closely connected to the quality and physical characters of feed-grade calcium phosphate products.Taken the concentrated phosphate rock as desulfurization reagent,the influences of dosage of desulfurization reagent,reaction temperature and reaction time on desulfurization effect were investigated under different concentrated phosphate rock concentrations,so as to provide a technical reference for producing qualified feed-grade calcium phosphate products.The results indicated that the SO4^（2-） could be effectively removed in dilute phosphoric acid（P2O5 mass fraction of 25.13%） and concentrated phosphoric acid（P2 O5 mass fraction of 48.16%） by using concentrated phosphate rock as the desulfurization reagent.In the dilute and concentrated phosphoric acid,when the dosages of desulfurization reagent were 5% and 8% respectively and controlling the reaction time in 3 h,the desulfurization reactions were basically completed,and the desulfurization rate could reach more than 80%.When the desulfurization time was 3 h,the reaction temperature had little effect on the desulfurization of dilute phosphoric acid.But in the concentrated phosphoric acid,the reaction temperature should be controlled beyond 50 ℃