Direct mineral tracer activation in positron emission particle tracking of a flotation cell

Understanding the complex interplay of physics and chemistry inside a flotation cell is the ultimate goal of most flotation research. Key to the development of a model of flotation is the ability to validate it from measurements of a real flotation system. This work uses positron emission particle tracking (PEPT) to track directly activated mineral particles, hydrophobic and hydrophilic, in a lab-scale flotation cell. In contrast to other particle activation methods the direct activation technique allows mineral particles with their original surface characteristics to be used in PEPT experiments. In this work the flotation separation investigated was the separation of hematite from quartz from a synthetic ore using a combination of an oleic acid collector and sodium silicate depressant. This work represents the first time in which particles of typical flotation size (−106 + 90 μm diameter) with real bulk mineral properties and surface chemistry have been tracked in a flotation cell. The results illustrate small particles flow behaviour in the cell for a hydrophilic particle. The trajectory and velocities of the tracer particle are shown as it is transported inside the flotation cell.</p

Statelessness Determination in the Netherlands

The Netherlands lacks an adequate mechanism for the identification of stateless persons, and is therefore not complying with its international obligations in the field of statelessness. Contrary to the position of the Dutch government, the existing procedures that stateless persons can appeal to are not in conformity with the relevant international standards. This paper contains a detailed analysis of the two procedures which have been invoked by the Dutch government in defence of the current statelessness protection and identification regime in the Netherlands, namely the registration of individuals in population registers, and the procedure for obtaining the so-called ‘no-fault’ residence permit. It illustrates that neither of the two are effective alternatives for statelessness determination. In addition, recent legislative changes that might affect the registration of statelessness in the Netherlands are discussed, and a proposal put forward by the UNHCR for a determination procedure in courts is evaluated