Development and testing of a novel micro-Raman probe and application of calibration method for the quantitative analysis of microfluidic nitric acid streams

To simplify and improve the safety of reprocessing nuclear fuel, the Micro-Raman technique was applied at the microfluidic scale with a view toward the on-line spectroscopic measurement of radioactive solutions.

Assessment of nanofiltration and reverse osmosis potentialities to recover metals, sulfuric acid, and recycled water from acid gold mining effluent

This work assessed the potential of nanofiltration (NF) and reverse osmosis (RO) to treat acid streams contaminated with metals, such as effluent from the pressure oxidation process (POX) used in refractory gold ore processing. NF and RO were evaluated in terms of rejections of sulfuric acid and metals. Regarding NF, high sulfuric acid permeation (∼100%), was observed, while metals were retained with high efficiencies (∼90%), whereas RO led to high acid rejections (<88%) when conducted in pH values higher than 1. Thus, sequential use of NF and RO was proved to be a promising treatment for sulfuric acid solutions contaminated by metals, such as POX effluent. In this context, a purified acid stream could be recovered in NF permeate, which could be further concentrated in RO. Recovered acid stream could be reused in the gold ore processing or commercialized. A metal-enriched stream could be also recovered in NF retentate and transferred to a subsequent metal recovery stage. In addition, considering the high acid rejection obtained through the proposed system, RO permeate could be used as recycling water.

Application of a New Technology for Reprocessing of Wastes Within the Framework of Rehabilitation of Uranium Mines Operated by In Situ Leaching

It is essential the environmentally safe industrial production of nuclear fuel especially in the case of uranium extraction by In Situ Leaching, when the environment and the deep extraction of uranium are important problems. In the presented paper it is studied the feasibility of the application of an electrodialysis method for the deep extraction of uranium and radium from liquid (acid) streams. It is proposed to apply a new electro-hydro-metallurgical [1] extraction and refining method to ensure the necessary extraction level of elements. In the same time the new method ensures the recycling of acids used in the process.

Functional plasticity of benthic macroinvertebrates: implications for trophic dynamics in acid streams

Functional plasticity of benthic macroinvertebrates was investigated over one year in four acid streams in the Vosges Mountains (northeastern France). The trophic position of macroinvertebrate species within the benthic food web was determined using gut content analyses. Diet analyses revealed that only 24–36% of biomass of putative shredders consumed leaf fragments, whereas up to 44% consumed benthic algae and bryophytes. Although most Nemouromorpha stoneflies were generalist consumers, several other taxa (e.g., Brachyptera seticornis, Chaetopterygopsis maclachlani) specialised on benthic algae and bryophytes. Our study showed that acid streams unexpectedly had very few specialised leaf-shredding species (e.g., Chaetopteryx villosa) that could explain the slow leaf detritus processing rates observed in these systems. Primary producers appear to be an alternative resource for shredders, playing an important role in supporting food webs in forested acid streams. The food web built in this study suggests that overlooking species-specific functional plasticity of invertebrates may result in a misconception of invertebrate community structure in acid streams.