用粗磷尾矿制备胶结充填材料

为解决湖北三宁矿业挑水河磷矿选厂重介质作业尾矿直接堆存存在的污染环境和土地占用等问题，在对该尾矿进行性能测定的基础上，开展了将其作为胶结材料用于充填采矿的可行性试验。结果表明：磷尾矿颗粒表面粗糙，有害元素含量低，可以作为胶结材料；磷尾矿为骨料制备的充填体不同龄期抗压强度均随灰砂比和料浆浓度增加而增强，但料浆浓度对充填体抗压强度影响相对较大；充填料浆坍落度、坍落扩散度和稠度均随灰砂比和料浆浓度增大而增大。为进一步降低胶结材料成本，还进行了粉煤灰部分替代水泥作为胶结材料的可行性正交试验。结果表明：粉煤灰的添加有利于充填体强度的增高，尤其是后期强度的增长；充填料浆坍落度随灰砂比、料浆浓度和粉煤灰掺量增大均先增后减，且影响程度由强到弱依次为灰砂比>料浆浓度>粉煤灰掺量。由于粉煤灰颗粒粒度细，且部分颗粒呈球形，使其在料浆中可以发挥滚珠轴承效应，减小了磷尾矿颗粒之间的摩擦力，进而提高了料浆的和易性；粉煤灰内部空隙多，随着粉煤灰掺量的增加，需水量也随之增大，导致充填料浆的黏稠性增大，阻碍了料浆中骨料的移动，进而使得坍落度和稠度随粉煤灰掺量增加呈现先增后降的规律。试验确定的胶结材料最佳配比为灰砂比0.250、料浆浓度80%、粉煤灰掺量1.00。利用粉煤灰和粗磷尾矿进行胶结充填具有显著的经济、环境和社会效益。

Cemented Paste Backfilling Material Preparation Using Coarse Phosphate Tailings

In order to solve the problems of environmental pollution and land occupation by direct stock of Phosphate Tailings(PT) from dense medium separation of Tiaoshuihe Phosphate Plant，Sanning Mining，Hubei Province.Feasibility tests of PT used as cementing material for filling in mining operation was conducted on the basis of its property measurement.Results indicated that：coarse PT can be used as cementitious material for its roughness surface and low content of harmful elements；Compressive strength of backing filling body in each age enhanced with the increase of cement-sand ratio and slurry concentration，while slurry concentration has more influence on compressive strength of filling body；filling pulp slump，slump flow and consistency all increased with the increase of cement-sand ratio and slurry concentration.In order to further reduce the cementing material cost，feasibility of cement partly replaced by Fly Ash(FA) as cementing material orthogonal experiment were conducted.The results showed that：addition of FA is beneficial for the strength enhance of filling body，especially long-term strength；filling slurry slumps first increase and then decrease with the increase of cement-aggregate ratio，slurry concentration and dosage of FA，and the impaction weakened by cement-aggregate ratio，slurry concentration，dosage of FA.FA can play a role in ball bearing effect for its fineness particle sizes and partly in spherical form，thus reduce the friction between phosphate tailing particles and improve the workability of slurry；there are so many internal spaces inside the FA，with the dosage increase of FA，water demanding also increases，which resulted in the viscosity increase of the filling pulp，hindered aggregate moving in the slurry，consequently，both slumps and consistence show first increase and then decrease rule with dosage of FA.The optimum ratio of cementitions mateials are cement aggregate ratio 0.250,sturry concentration 80%,dosage of FA 1.00.Using PT and FA in cemented backfilling industry has significant economic，environmental and social benefits.