Membranes for Gas Separation

Gas separation is of significant importance for many industrial processes including chemical purification, carbon capture, and fuel production [...]

An Introduction to Montmorillonite Purification

Purification of montmorillonite is a process to remove non clay minerals (gangue) such as calcite, feldspar, quartz, opal (C-T), and mica from montmorillonite ore. This is performed to make montmorillonite suitable for use in sensitive applications such as pharmaceutical, cosmetic, food, and advanced materials for nanotechnology. Gangue minerals in raw montmorillonite ores can cause serious health problems when used in pharmaceutics, cosmetic, and food industries and reduce material quality in advanced materials production. Montmorillonite purification can be divided into two main classes as physical and chemical purification. Physical purification processes are based on particle size difference between the gangue and montmorillonite minerals. Purification processes based on gravity separation are ineffective since the specific weights of gangue and montmorillonite minerals are very close to each other. Physical purification process includes sedimentation, centrifugal separation, aero separation, and sieving techniques. Chemical purification of montmorillonite is based on dissolution and so extraction of carbonates, metal hydroxides, organic materials, and silica, respectively, using different leaching techniques.

RECOVERY OF COPPER AND SILVER OF PRINTED CIRCUIT BOARDS FROM OBSOLETE COMPUTERS BY ONE-STEP ACID LEACHING

Over the years, the generation of Waste Electric and Electronic Equipment has been significantly increased, which leads to environmental and economic concerns. Thus, it is fundamental to develop treatment methods for these residues. Printed Circuit Boards are essential components of electronic equipments. In this sense, printed circuit boards are composed of remarkable metals, in particular, copper and silver at high and low concentrations, respectively. These metals can be recovered by the hydrometallurgical process followed by a chemical purification step. Therefore, the aim of this study was to leach silver and copper from two different printed circuit boards (memory board and motherboard) from obsolete computers by hydrometallurgical route based on only one-stage leaching in oxidant media. When compared to the motherboard, a higher recovery rate of Ag was obtained from memory boards 83% and 33%, respectively. Whereas, similar recovery rates of copper were observed for memory board and motherboard, 48% and 46%, respectively.

Measuring signatures of fuel irradiation in large particle samples

Scaled-down methods for the analysis of single particles of nuclear fuel using chemical purification and isotope dilution mass spectrometry reveal the heterogeneity of burnup and reaction along the axis and radius of a spent fuel rod.

Membrane Technologies as Environmentally Safe Methods of Waste Water Purification

A classification of chemical purification technologies, membrane processes, depending on the pore size in membranes is given. It has been established that environmentally friendly membrane methods for separating liquid media are an alternative to traditional methods for separating technological solutions and industrial waste waters.

RESEARCH OF TECHNOLOGY FOR EXTRACTION OF RARE AND NOBLE METALS FROM RESET CUES AND SLUDGE FIELD SOLUTIONS

Currently, in world practice, standard molybdenum concentrates undergo oxidative firing to obtain technical molybdenum oxide, which is the starting material for the production of ferromolybdenum. For the production of high-purity products, technical oxide is subjected to chemical purification by dissolving it in a solution of ammonia water. Molybdenum salts are precipitated from ammonia solutions, and Fe, Si, Cu, Al impurities are introduced with waste solutions from the technological cycle.