CFD Study on the Physical Behavior of Flue Dust in an Industrial-Scale Copper Waste Heat Boiler

The Flash Smelting Furnace (FSF) is one of the most common reactors for the primary smelting of copper concentrates. Its smooth operation depends on the availability and performance of the downstream Waste Heat Boiler (WHB). The WHB is especially sensitive to problems with its flue dust handling, such as the formation of accretions, which can lead to downtime and equipment failures. Due to the limited accessibility and the harsh conditions of the WHB, experimental studies are challenging. Therefore, CFD simulations can be a promising option to increase knowledge and evaluate a range of options. The present study investigates the physical behavior of flue dust in an industrial-scale WHB via a three-dimensional CFD model. Size-dependent particle sedimentation and the risk areas for flue dust accretions are predicted, finding good agreement with industrial experience and data from the literature. To make the evaluation of accretion risk zones possible, a new sticking function for flue dust is developed. The results are validated against dust samples. Finally, operational recommendations for minimizing flue dust accretions are derived.

Computational Approaches for Studying Slag–Matte Interactions in the Flash Smelting Furnace (FSF) Settler

Computational methods have become reliable tools in many disciplines for research and industrial design. There are, however, an ever-increasing number of details waiting to be included in the models and software, including, e.g., chemical reactions and many physical phenomena, such as particle and droplet behavior and their interactions. The dominant method for copper production, flash smelting, has been extensively investigated, but the settler part of the furnace containing molten high temperature melts termed slag and matte, still lacks a computational modeling tool. In this paper, two commercial modeling software programs have been used for simulating slag–matte interactions in the settler, the target being first to develop a robust computational fluid dynamics (CFD) model and, second, to apply a new approach for molten droplet behavior in a continuum. The latter is based on CFD coupled with the discrete element method (DEM), which was originally developed for modeling solid particle–particle interactions and movement, and is applied here for individual droplets for the first time. The results suggest distinct settling flow phenomena and the significance of droplet coalescence for settling velocity and efficiency. The computing capacity requirement for both approaches is the main limiting factor preventing full-scale geometry modeling with detailed droplet interactions.

Metallurgy at KGHM Polish Copper SA

Metallurgy of KGHM Polska Miedź S.A. is one of the world leaders in the production of copper. It is the result of high volume and quality production of copper and silver, as well as the use of modern technology direct to copper process in flash smelting furnace in HMG II. Soon this will be also the case for HMG I. The intention is to modernise, and upgrade technological processes within all the smelters to increase effectiveness, also to decrease production costs, and improve contamination of environment. In the year 2014 production of electrolytic copper increased about 2% in respect to 2013, and reached the record value 577 thousands ton. Production of silver increased 8% attaining value of 1256 ton. These perfect results were obtained through optimisation of smelting processes from one side, and rising the content of own concentrates, and foreign batches with higher content of precious metals. Production of metallic gold in 2014 was equal to 2,5t. Moreover KGHM is the third world producer of rhenium. They produce also lead technical and refined, as well as selenium, nickel sulphate, and platinum-palladium concentrate. The KGHM is also substantial producer of sulphuric acid, what is the direct effect of very efficient technology of desulphurisation of exhausts in the used metallurgical processes. The challenge for future is to increase retrieving of elements associated with copper production on every phase of the production. Due to the use of new technologies one expects also to achieve improved retrieving of other metals. Since 20% of KGHM revenue comes from silver, this is an important position in the overall balance of corporation focused mainly on copper exploitation. This is also why KGHM develops co-operations with scientific centres on the level bigger than laboratory (i.e. demo and/or pilot scales). The corporation is directly involved in research and development (subsidised national and international projects), while the value of these projects exceeds 200 mln PLN. There were created several collaborations with academic institutions targeting improvement of retrieval of energy from exploration processes, increase automation, remote control mining, and others. All of them are state of the art, and very modern technologies. KGHM must stay innovative, to preserve its market advantage. Metallurgy itself using own implemented technologies, resumes extended efforts to explore fully the richness of elements associated with the main metals.