中文摘要：

针对甘肃某低品位菱镁矿含钙脉石矿物白云石含量高、嵌布紧密、难以浮选分离的问题，开发了新型菱镁矿正浮选脱钙捕收剂BK434，并考察了其耐低温性能、适宜的矿浆PH环境与抑制剂条件。结果表明，BK434具有良好的选择性捕收能力和耐低温性能，针对MgO品位43．96％，杂质CaO含量3．91％和SiO2含量0．28％的原矿，工业试验获得了MgO品位46．04％的菱镁矿精矿，CaO和SiO2含量分别降低到1．60％和0．05％，MgO回收率为70．09％，较原生产指标回收率提高35％以上。

英文摘要：

A low grade magnesite ore in Gansu province is dif- ficult to efficiently separation because of the high content of finely disseminated dolomite. To obtain high flotation effi- ciency of dolomite remomal, a new collector BK434 is devel- oped. The resistance of low temperature, suitable pH envi- ronment of slurry and the suitable dosage of depressants is investigated in this study. The results show that the BK434 shows well selectivity and collection ability, as well as good resistance of low temperature. By the industrial experi- ments, from the low grade magnesite with MgO content of 43.96 0% the grade and recovery of obtained concentrate （cal- culated by MgO） are 46.04% and 70.09%, at the same time, SiO2 and CaO content are decreased from 3.91% and 0.28% to 1.60% and 0.05% respectively. The MgO recovery of obtained concentrate increased by 35% than the original one.