Search results for " Recovery"
showing 10 items of 561 documents
Recovery of magnesium hydroxide from real bitterns
Operational analysis of a novel reactive crystallizer for the production of Magnesium Hydroxide from waste brines
SELECTIVE CRYSTALLISATION OF MAGNESIUM AND CALCIUM HYDROXIDES FROM INDUSTRIAL WASTE BRINES: A PILOT STUDY
2021
In the last years, a rising interest has been focused on the valorization of waste brines from industrial processes, such as desalination plants. In most current scenarios, waste brines are disposed directly, or after being treated, into a receiving water bodies, often causing environmental concerns and, more importantly, renouncing to the possibility of using such a waste as source of valuable raw materials. In fact, these brines are typically rich in useful salts and minerals, whose recovery can increase the environmental and economical sustainability of the industrial process [1-2]. The ZERO BRINE EU-H2020 project aims at the development of technologies for the recovery of salts, mineral…
REVERSE ELECTRODIALYSIS HEAT ENGINE: Low-grade Waste Heat into Electricity
Our society is undergoing a progressive change about the life style and habits. The world population is continuously increasing with 7.6 billion of human beings in 2018, resulting in an increasingly demand of resources in terms of food, water and energy. The exploitation of the planet resources since the first Industrial Revolution, results today in an unsustainable condition, which requires fundamental changes. In particular, in the energy sector the adoption of fossil fuels as the main energy source for human beings’ activities resulted in a strong impact on our planet, leading to climate changes and environmental pollution. Nowadays these aspects have induced society to a substantial cha…
Reverse electrodialysis with NH4HCO3-water systems for heat-to-power conversion
2017
Abstract A Reverse ElectroDialysis Heat Engine (REDHE) system operating with “thermolytic” ammonium hydrogen-carbonate (NH4HCO3) aqueous solutions as working fluids is studied. The engine is constituted by (i) a RED unit to produce electric power by mixing the solutions at different salinity and (ii) a thermally-driven regeneration unit including a stripping and an absorption column to restore the initial salinity gradient thus closing the cycle. In the present work only the RED unit and the stripping column are taken into account. In particular, a simplified integrated process model for the whole cycle was developed: it consists of (i) a lumped parameter model for the RED unit validated wi…
Experimental investigation and modelling for sulphuric acid recovery by diffusion dialysis
2018
Sulphuric acid is known to be one of the key inorganic acid and has been widely used in chemical reaction and metal industries for surface treatments as in the copper electroplating process. During these processes, large amounts of waste sulphuric acid solution are generally generated, containing high concentrations of metals and acid. The possibility of recover and reuse the sulphuric acid in the process could avoid environmental contamination and reduce costs of the disposal. Among several separation methods, diffusion dialysis (DD) is becoming more and more attractive thanks to the recent important advances in ion exchange membranes (IEMs) field and because of its clean nature and operat…
Development of a pilot plant for the recovery of magnesium hydroxide from waste brines
Waste brines from various industrial processes, mainly from saltworks, are an important source of minerals, such as magnesium, table salt and potable water.
Diffusion dialysis for the treatment of H2SO4-CuSO4 solutions from electroplating plants: Ions membrane transport characterization and modelling
2021
Diffusion dialysis (DD) is proposed to separate and recover mineral acids and transition metals from electroplating industry process waters promoting a circular approach of resources recovery. In this work, a DD module with two anionic membranes (Fumasep FAD and Neosepta AFN) are used for the separation of H2SO4 from Cu2+ containing solutions. The membrane performances with sole H2SO4 solutions (0.2–2 M) and sole CuSO4 solutions (0.8–1.1 M Cu2+) and with mixtures of H2SO4 (0.6 M) and CuSO4 (0.2–1.1 M Cu2+) as feed are studied. H2SO4 recovery efficiency decreases as the concentration of acid increases. For H2SO4 solutions, the water drag flux from the retentate to the diffusate prevails agai…
Modeling and Design of Membrane Process Recovery of HCl and Metals from Pickling Solutions
2018
Abstract Hydrochloric acid pickling is one of the key steps in the hot-dip galvanizing process. It is a process widely used as a chemical pre-treatment method for cleaning, where metal surfaces with oxides are immersed into an acid solution. During the pickling process, the acid concentration decreases with time while the metal is accumulated. Thus, the efficiency of the pickling solution decreases and fresh solution must be used. Continuous regeneration of pickling solutions enhances pickling rate and process performance, but also minimises industrial wastewater disposal and chemicals consumption. The recovery and recycling process of valuable substances (e.g. acid and metals) can be accom…
An integrated approach for HCl and metals recovery from waste pickling solutions: pilot plant design and operations
Continuous regeneration of industrial pickling solutions and recovery of valuable materials are implemented in a pilot-scale plant including diffusion dialysis, membrane distillation and reactive precipitation units. The main results of the preliminary assessment of on site operation are presented. Different hydrochloric acid concentration and metals composition were investigated and the performance of the system were analysed in terms of quality of recovered compounds, energy efficiency and environmental footprint.