Gold Mine Tailings In Cement Production Application And Immobilization Of Heavy Metals

Up to now, the stock of metal mine tailings pile in our country has amounted tomore than5billion tons, and it is growing rapidly at a speed of600million tons per year,especially, the annual gold tailings emissions is up to24.5million tons. The metal minetailings remain possibilities to reuse, long time piling will not only wastes the resources,but also takes up a lot of land, pollutes the environment, and threatens human health. Inrecent years, many researchers focus attention on the tailings utilization, and make alot of achievements.In this paper, slag cement was calcining through simulating cement production process. The free lime content and gel properties of the cement clinker were determined aswell as the phase composition and microstructure of the cement clinker and its hydration products. These results were compared with Portland cement to find out the possibilityof gold mine tailings cement production. This article also studied the dissolution of heavy metals and immobilization in the calcined cement to discuss the environmental security of using gold mine tailing slag in cement produce, the results are as follows:1. The cement clinker calcined by gold tailings under the temperature of1350℃has the similar structure and hydration products to Portland cement., during this process,the early strength is slightly weaker than the ordinary cement, but later it increasesquickly, ultimate strength is higher than that of ordinary cement.2. The curing rate of heavy metals by cement is very high. Under the experimentalcondition, all heavy metals solidification rate were greater than97%. Corrosiveenvironment on the impact is not big and small aperture is more advantageous toimmobilization of heavy metals.3. Lead, zinc and chromium will change the main hydration products of cementcomposition and lattice structure, when heavy metal element content in cement is high.They are fixed through the formation of sediment. Nickel, cobalt and cadmium has littleeffect on the hydration products of cement basic. They mainly through adsorption of hydration products and the sealing process of cement are fixed.4. Gold slag can be produced into cement, the structure and mechanical propertiesof this cement meet the requirements of cement. Almost all the heavy metals in slag arefixed, and there is no impact on surroundings.