Gemini表面活性剂体系下钙质磷矿中白云石的可浮性研究

Study on the floatability of dolomite in calcareous phosphate rock under Gemini surfactant system

通过接触角测量和浮选试验研究碳链长度为8、10、12的Gemini表面活性剂体系下钙质磷矿中白云石的可浮性的变化。结果表明,水在白云石表面的接触角具有时间依赖性,50 s形成平衡接触角。Gemini阴离子表面活性剂b8、 b10、 b12在白云石表面的吸附符合表面活性剂在固体表面吸附的两阶段模型,同浓度下表面活性剂碳链越长,白云石接触角越大,可浮性越强。b12作用下,白云石最大接触角从69.6。增大到120。,1-cosθ为1.55,与胶磷矿的最大接触角差值达35.6°,表明b12可促进白云石的疏水上浮。以 b12作为捕收剂进行白云石和胶磷矿的单矿物浮选试验,结果显示在酸性条件下胶磷矿受抑制,pH=5.5时白云石和胶磷矿上浮率差值达50.22%,二者易于实现浮选分离。对原矿P2O5品位为23.72%的钙质磷矿进行直接反浮选,结果表明,在磨矿时间9 min,-0.074 mm 74.8%,硫酸用量8 kg/t (pH=5.5),三聚磷酸钠用量1.2 kg/t,b12用量1.15 kg/t条件下,b12可将磷矿P2O5含量提高至26.41%,b12有继续研究的价值。

The change of floatability of the dolomite in the calcareous phosphate rock was investigated by contact angle measurement and flotation test under the Gemini surfactant system with carbon chain lengths of 8,10,12.The results show that the water contact angle on dolomite surface is time dependent,an equilibrium contact angle was formd after 50 s.The adsorption of gemini anionic surfactants b8,b10 and b12 on dolomite surface obeys two-stage model of surfactant adsorbed on the solid surface.At the same concentration,the longer is the surfactant carbon chain,the greater is the contact angle and the floatability,the lower is the sedimentation yield of phosphate rock.Under the actiont of b12,the maximum contact angle on dolomite surface increased from 69.6。to 120。,and 1-cosθ=1.55,the maximum contact angle difference with the phosphate rock is 35.6°,it shows that b12 can promote the dolomite floating.The single mineral flotation test of dolomite and collophanite were carried out with b12 as the collector.The results shows that the phosphate rock is inhibited under acidic conditions,and the difference of the floating rate between the dolomite and the phosphate rock is 55.22% and they are easy to separate at pH=5.5.The direct reverse flotation of calcareous phosphate rock which P2O5 grade 23.72% shows when the grinding time was 9 min,-0.074 mm mesh accounted for 74.8%,sulfuric acid dosage 8kg/t(pH=5.5),sodium tripolyphosphate dosage 1.2 kg/t,b12 dosage 1.15 kg/t,b12 can increase the P2O5 content to 26.41%,and the flotation index is better than oleic acid.b12 is value in continuing.