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The deposition of insoluble inorganic substances on heat exchanger surfaces has a strong negative influence on the heat transfer and thus on the performance of the apparatus and the process. The analysis of the deposits is a crucial step towards the development of suitable technologies for scaling mitigation and prevention. Such analysis, however, is challenging and often requires advanced instrumentation and sample preparation. To overcome this problem, we present a straightforward analytical approach based on Fourier-transform infrared (FTIR) spectroscopy. We demonstrate that FTIR spectroscopy is a powerful tool for the chemical analysis of inorganic deposits. For example, it can identify the common anions in scales such as sulfates and carbonates. It can even distinguish between salts with the same anion but different cations such as calcium and sodium. Test measurements are performed on the deposits from a domestic water cooker and from the evaporator of a seawater desalination pilot plant.

Seawater brines, generated either by natural or anthropic processes, often cause significant environmental issues related to their disposal. A clear example is the case of brines from desalination plants, which can have severe environmental impacts on the receiving water body. On the other side, brines can represent a rich and appealing source of raw materials, especially when they are very concentrated, as it happens with bitterns (i.e. exhausted brines) produced in saltworks. In particular, magnesium concentration can reach values up to 30-40 kg/m3 of brine, which is 20-30 times that of typical seawater.\ud An experimental campaign has been carried out in the present work for assessing the potentials for magnesium recovery from concentrated brines. Real brines were collected from the final basins of the saltworks operating in the district of Trapani (Sicily - Italy).\ud Experiments were performed both in a semi-batch and in a continuous 5 litre crystalliser operating by a reactive precipitation process. NaOH solutions were adopted as standard alkaline reactant in order to assess the influence of all operating parameters and reactor configuration on the recovery efficiency and purity of the Mg(OH)2 powder produced.\ud Results have highlighted a very promising strategy for the recovery of Mg from concentrated brines, which could be scaled-up and applied to a number of different scenarios, including existing saltworks and newly designed integrated cycles for Zero Liquid Discharge desalination

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