New Sensor Aids Rare Earth Extraction from Acid Mine Drainage

Rare earth elements appear in more than 200 consumer products. The race is on to source these elements from abundant and environmentally damaging mining waste.

Rare Earth Extraction using Solvent Extraction: Which Factor Has the Most Significant Impact?

Using a two-level factorial design, a study was undertaken to change the parameters impacting the recovery of rare earth from rare earth mixture. The experimental design was used to screen and identify the major contributing aspects to rare earth recovery. The experiment aims to isolate samarium from a mixture of samarium, europium, and gadolinium. Factors involved consist of pH (pH 1 and pH 6), acid type (nitric acid and hydrochloric acid) and concentration (1.0M and 5.0M), mixing duration (30 min and 120 min), feed composition (20% samarium and 80% samarium), type of diluent (hexane and chloroform), temperature (room temperature and 60°C) and organic to aqueous phase ratio (1:1 and 2:1). The results showed that the samarium recovery was in the range of 0.98% to 90.88%. Based on analysis variance (ANOVA), five factors significantly affect the samarium recovery out of eight factors explored. The five factors according to the most significant order are pH> feed composition> organic to aqueous phase ratio>acid concentration>acid type>mixing duration>type of diluent> temperature. Statistical analysis shows that the linear model is significant, with the value of R2 is 0.9886. Based on the statistical data, five significant variables influence the separation of samarium. This research shows that two-level factorial design can anticipate significant variables impacting rare earth separation, particularly samarium, in the solvent extraction process.

Challenging pollution and the balance problem from rare earth extraction: how recycling and environmental taxation matter

Rare earth element extraction induces environmental damages and the balance problem. In this article, we show that recycling can challenge both problems in a two-period framework. We also find other results depending on the amount of scrap that can be recycled. If the recycling activity is not limited by available scrap, it does not change extraction in the first period. Environmental taxes on extracted quantities reduce extraction and favor recycling. But if the recycling is limited, the extractor reduces extraction in period one, adopting a foreclosure strategy, and environmental taxes can decrease recycling. In all cases, environmental taxes are never equal to the marginal damage from pollution, in order to take into account the recycling effect.