Regionally, there has been a lot of focus on the advancement of sustainable arctic industry and circular economy activities within process industry in the Finnish Lapland. In this study, collaboration between university and industry was established facilitated by regional development actors to develop and pilot test a sustainability assessment approach taking into account previous work in this field. The industry partners in this study were a biorefinery investment in the first case and a slag processing service in the second case. As a result of the joint efforts, novel sets of environmental and economic sustainability assessment indicators and associated sub-indicators were developed and the existing set of social indicators was updated. Moreover, environmental and social sustainability assessments were implemented in the biorefinery case accompanied by a separate evaluation of regional economic impacts. In the slag processing case, environmental, economic and social sustainability were assessed. The results of the sustainability assessments indicated very good level of overall performance in both cases. However, specific elements that contributed to lower level of performance included lack of specific sustainability management and reporting approaches and need for better performance in supply chain sustainability, monitoring of greenhouse gas emissions, life cycle thinking and circular economy training. The expected effects of the planned investment on the regional economy were very positive based on the results of the evaluation.

To save freshwater resources and comply with environmental regulations, minerals processing operations are transitioning to partially or fully closed water circulation. However, the accumulation of electrolytes and the addition of reagents lead to changes in water composition and may compromise flotation performance and plant maintenance. As a consequence, costly modifications are often required to cope with these challenges. Therefore, knowledge about water quality variation owing to closed water circulation and its potential effect on the flotation performance is crucial. The experimental methodology presented in this paper targeted three main objectives: (1) predicting the tendency of the accumulation of elements and compounds into the process water during comminution, flotation, and storage in tailings facilities; (2) establishing a relationship between laboratory results and plant historical water quality data; and (3) predicting the potential effect of recycling water on flotation performance. The results obtained with Boliden Kevitsa ore showed a good correlation between the water matrix of the actual process water on-site and that obtained in the ore dissolution tests done in the laboratory. The final water composition came close to the process water in terms of major elements and some of the minor elements. Additionally, the work presented in this paper demonstrated that a dissolution loop allowed us to predict the potential impact of the recycling water on the ore flotability. This methodology could serve as an aid for predicting water quality matrix variation and designing closed water circulation systems at existing and new plants.

The changes in water quality owing to recirculation of water in mineral processing plants can compromise the plant performance as well as maintenance needs. Therefore, mining process water quality assessment is becoming critical. Nevertheless, very few studies have investigated the suitability of the current analysis methodology practiced in certified laboratories for evaluating mining process water quality. This article presents two case studies to highlight the major issues encountered when performing sampling for physicochemical and chemical parameters in process water at two European mine sites using procedures from two certified laboratories. In addition, microorganisms were shown to be abundant in process waters and likely affect the mining water chemistries. However, the protocols used for microbial studies are not optimal for mining process samples, and need to be improved. The results showed difficulties in providing satisfactory results when analyzing control samples. Additionally, the analysis results presented a strong imbalance in TDS and sulfur compounds. Several potential causes associated with the poor quality of the analysis results have been outlined with a specific focus on the preservation methods. A literature review on the degradation of thiosalts suggested that the current preservation procedures are not suitable for preserving sulfur compounds. Moreover, the results indicated that the water matrix strongly influenced the validity of the chosen analysis method. In conclusion, the analysis methods should be customized for the different mining water matrix types in order to ensure the accuracy and reproducibility of the results.

Techno-Economic Analysis of Simplified Microcrystalline Cellulose Process