Utilization of Bergama Gold Tailings as an Additive in the Mortar

Abstract

Bergama is the first gold mine in the history of Turkish Republic and currently one of the operating gold mine in Turkey. About 3 tons of gold and equal amounts of silver are mined each year. The estimated ore reserves at the Bergama gold mine are 2.4 million tons with about 10 g Au per tonne of ore. About 277.882 tons of the tailings slurry of gold mine treatment is produced every year during the recovery of gold. Increasing amounts of tailings slurry cause a problem in large disposal areas. Therefore, the recycling of this kind of slurries into useful materials is quite important in terms of economic and environmental aspects.

The aim of this study was the investigation of utilization of the gold tailings as an additive material in Portland cement production. For this purpose, the effects of the gold tailings on the compressive strength properties of Portland cement were investigated. Cement mortars were prepared with Portland cement (CEM I 42,5 N) and dried gold tailings. Gold tailings with different ratios (5, 10, 15, 20, 25%) were added as cement additive in the mortar. The fresh properties of mortar such as consistency and setting time were investigated by using Flow table and Standard Vicat apparatus. The mortars were tested for compressive and flexural strength values after 3, 7 and 28 days. Mineralogical composition and microstructure of the 28-day mortars were determined by X-ray diffraction (XRD) and scanning electron microscope (SEM). According to results, it can be concluded that the tailings are eligible for mortar aggregate and the optimum ratio of gold tailings is 5%.

Keywords

• gold tailings; setting time; compressive strength; XRD; SEM

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