New Outotec tin smelter in Bolivia

Outotec Ausmelt tin smelting technology

At the heart of the EMV project is the Outotec Ausmelt TSL technology. This technology combines the use of an Ausmelt top submerged lance within a simple well sealed, non-rotating Ausmelt furnace that allows for best practice environmental performance. The top submerged lance allows for the direct injection of air, oxygen (if required) and fuel directly into a molten bath. This results in rapid mixing and efficient reaction of materials within the furnace. The combustion of fuel at the lance tip also provides heat input to the furnace at the best location. With an ability to control the individual lance flows and furnace feeds, control of the process is very flexible.

With such inherent flexibility the Outotec Ausmelt TSL technology has been applied to a wide range of applications. For tin, it can be applied to concentrates and secondary feeds.

Outotec Ausmelt TSL technology is now accepted as being the technology of choice for new tin smelters or for the upgrading of existing tin operations currently using conventional technology, as was the case for the EMV project.

Project overview

Outotec’s scope of supply in the EMV project included the control system, lances and furnace standby burner along with a range of commissioning services. The project also included the supply of a novel lance handling system fully designed by Outotec engineers. The system consisted of a traction drive (rather than the conventional drum hoist), providing a much smaller and simpler way for positioning the lance.

One of the unusual aspects of this project was the site location. At an altitude of 3,700m above sea level, significant challenges with respect to equipment supply were posed. This was the highest altitude installation of an Outotec Ausmelt furnace and associated core equipment, including furnace lances, furnace cooling system, control system and motorized equipment. All were carefully evaluated and, where necessary, their designs were modified to operate successfully under these low air density and atmospheric pressure conditions.

Construction and commissioning

Outotec process, mechanical and control engineers provided specialist cold and hot commissioning support during the construction and commissioning phases of the project. Cold commissioning commenced in May 2015, followed by operator training in August and finally heat-up of the furnace in September. Operators were sourced from other areas of the EMV site and were thus reasonably well versed in various aspects of tin metallurgy and smelter operations. Consequently, the primary focus during training and hot commissioning was to pass on knowledge and experience unique to tin smelting with Outotec Ausmelt TSL technology.

Furnace operations quickly ramped up to the design feed throughput, despite a number of equipment related issues impacting on furnace availability (as is often the case during the start-up of an integrated plant such as this). Another of the challenges during this period was bringing operators up to speed with a more automated approach to monitoring and control of the process and plant equipment via the control system. This differed significantly from the hands-on approach that EMV was accustomed to from its time spent operating the traditional tin smelter. 

Current plant operation

Currently, the Outotec Ausmelt TSL tin plant is operating well, with typically 15 - 20 tonnes of tin metal being tapped in each batch. Through close collaboration with EMV to resolve issues encountered on-site, both during and after the period for which Outotec personnel were present on-site, a strong relationship has been established.