BCL smelter rebuild project

More than four decades later and primary smelting is still done with Outotec Flash Smelting Technology. This is complimented by two Delta electric furnaces for slag cleaning. The matte is converted through the use of three Peirce-Smith converters and one Converter Slag Cleaning Vessel (CSCV) for cobalt recovery enhancement. Norilsk Nickel relinquished its 6% shareholding making the government of Botswana the 100% shareholder of BCL.

Project overview

The primary scope of the project Outotec was involved in focused on modernization of the nickel Flash Smelting Furnace (FSF). Contracting was structured in the form of two primary agreements.

• Part 1 included design, engineering as well as fabrication and supply
• Part 2 was established as a service level agreement for technical support during the installation, operation and maintenance period limited to 36 months. 

The scope of Outotec's work included basic design, detail design of the new FSF, delivery of new advanced cooling elements with Outotec Sentinel Cooling Water Monitoring System and integrating them to the furnace. The delivery scope of refractory material and steel structures were shared between Outotec and BCL. The equipment was delivered to the BCL site in April 2015.

The service level agreement included a general audit on BCL operations and maintenance, expert supervision oversight during installation and commissioning, preventive maintenance planning, equipment maintenance support and spare parts availability plan. A key component of the service level agreement is access to an emergency support protocol that includes 24 hr call line and 48 hr on-site response.

Work at the site

The modernization was done as a full shutdown of the smelter from July 15 to November 12, 2015, and required the complete demolition of the FSF down to grillage beams. This included the settler, uptake and reaction shafts as well as all cooling water headers and circuits.

During this period BCL conducted maintenance, repairs and upgrades of several of the components upstream and downstream of the FSF. This included an additional new cooling tower system, major repairs to the boiler and heat exchangers, an air and steam drying plant and a rebuild of the primary slag cleaning furnace. A combined team of Outotec technical experts from Finland and South Africa took charge of the on-site installation, commissioning and start-up of the Outotec contractual supply components. 

On-site continuity for the full duration of the shutdown was provided by the Project Coordinator Chris van Heerden. This enabled optimized coordination for liaison on logistics and resource movements.

The site supervision came from Outotec's product line experts, and was divided into two parts. The first part took place during the demolition and initial installation phase in August-September, and the second during the start-up in October-November 2015.

The first supervision group consisted of five members, namely, Kaarle Peltoniemi, Mikko Piirainen, Markku Haukkala and Reijo Hynönen. The team arrived on site in the beginning of August and took care of the supervision of the FSF and the primary cooling water system installation phase. Refractory supervision was provided by a team from RHI who were also present on the site in due time. The initial team was complimented by Päivi Suikkanen and Iina Vaajamo who arrived on site at the end of August to execute a two week BCL management and operator training plan. The first week focused on process training consisting of theory of flash smelting, FSF process, operation and maintenance. The second week focused on the cooling system, consisting of introduction and use of Outotec Sentinel, operation, maintenance and upset conditions. The BCL students were very active participants, and asked a range of questions which led to fruitful discussions. The training provided a wonderful opportunity to become acquainted with BCL management and operators. Various in depth discussions relating to the operations and process challenges helped to build a relationship of trust between BCL and Outotec people. These kind of discussions and sharing of ideas is really valuable for both groups as a basis for knowledge exchange.  

Outotec’s automation specialist Valtteri Sonninen represented the second supervision group and arrived on-site early October to supervise the Sentinel header and software commissioning. Vaajamo returned to site in late October to provide hands on practical training to BCL operators on the Sentinel System and to assist Sonninen with commissioning activities. The site looked quite different from what it had previous to the team's departure in September. The FSF was up and running, the cooling element and headers were in their places with new platforms, and the copper piping had been installed. The Sentinel software hands-on sessions were organized during the shifts with each operator on duty. This format of training enabled operators to pose immediate questions during real-life cases to which the instructor could provide. 

After the rebuild

Despite of the tight delivery schedule and some obstacles that every project has, this was a successful project to work with (and not just the possibility of escaping Finland to sunny Botswana in autumn).  It was a great pleasure to work with BCL's team, and our co-operation continues with the service level agreement. We wish BCL a long campaign life and good quality matte with the new Flash Smelting Furnace.