Chlorination roasting process for extraction of valuable metals in boron clays

Abstract

Boron is one of the most important underground sources in Turkey. As a result of the boron enrichment process, large amount of wastes are accumulated, and this situation threats to the environment. There are many studies on the industrial use of boron wastes as additives in some sectors such as cement, concrete, brick, and ceramics. However, there are limited studies on the recovery of valuable metals in the content of these wastes. Thanks to recovery of these metals through the wastes; Not only the amount of waste is reduced but also contribution to the national economy is provided. It is determined that boron wastes, in particular, clay wastes contain in a considerable amount of valuable metals like lithium, rubidium and cesium. Lithium is used in battery production with its unique electrochemical reactivity. Rubidium and cesium have similar chemical properties and can be used interchangeably of each other in most sectors like night vision equipment, telecommunication systems, new technical materials and energy. Lithium is found in lepidolite mineral. Rubidium and cesium are obtained as the byproduct of lithium mining. Also, they can be extracted in small quantities from salt lake brines. In this study; the boron clay, taken from Emet region in Kutahya, was applied chemical roasting process using calcium chloride and sodium chloride with a mass ratio of the boron clay/calcium chloride/sodium chloride of 1/0.3/0.2 at 950 degrees C for an hour. Then the melted mixture was leached with water for an hour with solid/liquid ratio of 0.02. Extraction of over 85% was achieved for each metal.