Research on Low-Cost Cementitious Solidification Materials for Solid Potash Tailings in Laos
In order to solve the problems of difficult solidification of tail salt and old brine of potash tailings as well as the high cost of solidification,the strength-proportion tests of traditional conventional cementitious materials and tail salt was carried out,and the solidification characteristics of tail salt were analyzed.According to the characteristics of tail salt,two new cementitious materials were developed,and the solidification strength of new cementitious materials with tail salt under different cement-sand ratio and mass concentration was explored.The research results indicate that using calcium oxide as a cementitious material,the solidification effect after mixing with tail salt is poor when the cement-sand ratio is large,and the compressive strength of the test blocks is low.As the cement-sand ratio decreases,the optimal strength of the test blocks only reaches 1.20 MPa.Magnesium oxide can significantly enhance the strength of the tail salt backfill,and the maximum strength of the test blocks after 28 days can reach 22.06 MPa.When fly ash and steel slag are used as cementitious materials,the tail salt and old brine cannot achieve solidification and are not suitable as cementitious materials for tail salt.The strength of the 1#new cementitious material mixed with tail salt after solidification is relatively low,with a maximum strength of only 1.20 MPa,which cannot meet the strength requirements of the backfill.However,it can reduce the roughness of the surface of the backfill.When the cement-sand ratio is 1∶8 and the slurry mass concentration is 72%,the 28th day strength of the test blocks of the 2# new cementitious material can reach 3.17 MPa.Compared with magnesium oxide,when the strength of the test blocks reaches 2.00-3.00 MPa,the filling cost of the 2# cementitious material is reduced by more than 50%.
Potash tailingsTail saltCementitious solidification materialsStrength of backfillFilling cost