The Role Of Surface Active Agent In A Diaspore Flotation System

In this paper we firstly studied the relationship between crystal structures, surface properties and floatability of diaspore and kaolinite.Some factors affecting the floatation of bauxite were found by investigating the floatation behavior of the two minerals in single pure mineral test system with different surfactants as collector. Corresponding measures were conducted also.Meanwhile the action mechanisms between collectors and minerals has been researched in details.1. The crystal structures,surface properties and floatability of diasplore and kaolinite.In the crystal lattice of diaspore,aluminium-oxygen octahedron forms double chains. In the crystal lattice of kaolinite aluminium-oxygen and silicon-oxygen tetrahedron forms layer type silicate mineral at the ratio of 1:1.Abundance of aluminium atom on the surface of diaspore is 1.7 times larger than that on the surface of kaolinite.Absorbing or ionizing H⁺ result in charging on the surface of diaspore; Zata-potential of diaspore is variable with pH in the solution. Charging mechianism of on the surface of kaolinite are two kinds.The charge of lateral surface result from absorbing or ionizing H⁺ , and the charge of layer surface owe to crystal lattice displacement of cation.The latter is related to the degree of displacement and indpendent of pH value in solution.the point of zero charge(P.Z.C) of diaspore is pH5.5, and pH3.3 for kaolinite.2. The effect of the surfactants on the two system:In the system of floatation of diaspore, surfactants OL2, OL3 and OL4 can improve floatability of OL1, The recovery of Al₂O₃ is add up 12%. the addition orders can affect the results, the best way is to addict the combination medicament mixed previously. we also get the proportion of the four surfactants(30:2:1:8) (quantity proportion ).Studing the factors of temperature and metal cation,we found that the floatability resisting to the low temperature and metal cation are improved with the addition.In the system of flotation of the kaolinite, surfactants OL2, OL3 and OL4 can affect the floatability ,and the addition orders is a very impotant factor. The floatability can be improved with the append the surfactant preceding to OL1, conversely, the flotability can be impared with appending the surfactantfollowing OLl.3. The action mechanisms between collectors and minerals.The main forms of the sodium oleate exists in the solution is double molecule and oleic acid-soap when the pH is about 9, and the content of the oleic acid-soap,which is very important to the flotation of the diaspore,come to the maxium.The surfactants form the mixed clusters ,which can improve the dissolution and emulsification.we can find the mixed cluster on the change of the surface tension of the solution.Measuring the angles of the soaked ore and Zeta-potential of the ore, further study on the mechanism of adsorption of OLl on the diaspore proved that the addiction of surfactants 0L2n OL3> OL4 can reduce Zeta-potential of the ore, accelerate adsorbtion of the surfactant OLl on the diaspore and increase the contact angles of the soaked ore.From the tests of the resultant on surface of the diaspore with infrared-ray,we can find the trend that physical adsorbtion turn to chemisorption gradually.4. The practice of the floatation of bauxiteFrom the preceded experiments ,we found it was easy to separate the diaspore from kaolinite,which also had been proved in the following experiments of the artificial mixed mine, The addition of OL2> OL3 (OL4) could improve the recovery and the concentrate grade,the recovery of AI2O3 is add up 15.17%,the concentrate grade of A/S is add up 6.49.