Lithium has become a strategic element, as it plays a crucial role in battery technology. Therefore, many efforts are being made to extract lithium from primary sources, while lithium recycling is almost nonexistent. In this paper, we report on a novel alkaline mechanochemical approach for the recycling of end-of-life glass-ceramics, which involves lithium extraction, zeolite syn-thesis, desilication, and lithium precipitation. Special attention has been paid to a holistic approach, with each byproduct having a designated application. Optimal parameters for lithium extraction such as sodium hydroxide concentration, rotational speed, and ball-to-powder ratio were achieved at 7 mol/L, 600 rpm, and 50:1 g/g, respectively, resulting in high yields of 83.8% (60 min) and 92.4% (120 min). Desilication of the solution resulted in a removal efficiency of 96.3% with calcium silicate as a value-added byproduct. Lithium could be recovered as phosphate with a high purity by adding phosphoric acid. Moreover, the zeolites synthesized during this investigation were analyzed by powder X-ray diffraction, Fourier transform infrared spectroscopy, and N-2 adsorption/desorption analysis. In addition, selected zeolite samples were investigated as potential adsorbents for the removal of heavy metal ions (Cu2+, Ni2+, Pb2+, and Zn2+) from aqueous solutions.

Abstract Veröffentlicht in der Reihe Analytische Methoden zur Prüfung gesundheitsschädlicher Arbeitsstoffe: Luftanalysen , 7. Lieferung, Ausgabe 1992 Der Artikel enthält folgende Kapitel: Grundlage des Verfahrens Geräte, Chemikalien und Lösungen Geräte Chemikalien Vergleichsstandards Filterimprägnierung Probenahme und Probenaufbereitung Hochdruckflüssigkeitschromatographische Arbeitsbedingungen Analytische Bestimmung Kalibrierung Berechnung des Analysenergebnisses Beurteilung des Verfahrens Präzision Diskussion

A mechanochemical synthesis of a co-polymer of salicylic acid and formaldehyde is reported. New IR absorbance bands found after the performance of the mechanochemical synthesis are attributed to the formation of a salicylic acid–formaldehyde co-polymer. Dislocation deformation along slide planes in the salicylic acid structure occurs in the course of the mechanochemical activation causing no essential changes in the more stable hydrogen bonds net. The weaker inter-layer bonds in the acid structures are broken during activation, but are restored soon after the completion of the process. Polycondensation reaction occurs as a result of the mechanochemical process of the salicylic acid–formaldehyde mixture. The obtained co-polymer is a chelating agent capable of binding Pb2+, Cu2+, and Fe3+ ions. A comparison was made of the ion exchange capacity and metal ion binding capacity of the mechanochemically produced co-polymer with the co-polymer synthesized using the conventional “wet” method.

Controlled-release systems (CRSs) for the insect growth regulator cyromazine (Neporex), as a larvicide against Culex pipiens (Culicidae) mosquitoes, are under development. Despite promising results obtained previously for both in vitro (dissolution tests) and in vivo systems (mosquito larvae floating on water surfaces), it was evident that the CRSs did not remain afloat for sufficiently long times. The present study was thus conducted to determine the relationship between the process parameters and the potential contact time of the active ingredient with the mosquito larvae. A series of CRSs were prepared by an extrusion process, alone or in combination with a supplementary coating. The active ingredient was incorporated into the matrix or the coating. The matrix comprised low-density polyethylene 600 and perlite, and the coating, a polyurea with or without the addition of paraffin wax. The study showed that the cumulative release of the active ingredient into water could be controlled by manipulating the preparation techniques, the types and concentrations of inert materials, and the concentration of the active ingredient.

The effect of long-acting formulations of plant growth factors (PGFs) on rooting was investigated in a mung bean cuttings model system, in five semi-hard olive cultivars and in a range of garden plants. The PGFs, which comprised the hormones indole-3-butyric acid and paclobutrazol, the nutrients N, P, and K and trace elements, and the protecting agent Sportac, improved rooting and promoted the development of the root system. The PGFs were formulated into encapsulated controlled-release systems by means of an extrusion technique, a coating method, or their combination. Chemical and biological testing of the encapsulated formulations showed a prolonged release pattern for each of the ingredients. The controlled release PGF delivery system presented in this study may serve as a platform for a wide range of horticultural uses of premixed formulations contributing to the efforts towards a safe environment.

The release characteristics of encapsulated formulations containing a combination of plant growth factors (PGF)—plant hormones (IBA, paclobutrazol), nutrients (fertilizers, microelements), and fungicide (prochloraz)—were studied. The formulations were prepared by encapsulating the active ingredients in a polyethylene matrix and, in some cases, subsequently coating the product with polyurethane. Dissolution experiments were carried out with both coated and non-coated formulations to determine the sustained release patterns of the active ingredients. The PGF controlled-release systems obtained have been shown to promote development of root systems, vegetative growth, and reproductive development in cuttings, potted plants, or garden plants of various plant species. These beneficial effects are attributable to the lasting and balanced PGF availability provided by these systems.

Data of drop size and mass transfer in the extraction of Cu from an aqueous solution into a solution of LIX 84N in kerosene for several lengths of motionless mixers of the Sulzer type SMV-4 and 3/4″ diameter is presented. Previous data obtained with same static mixers and other types of mixers will also be presented for background and comparison purposes.

The modified electroresistivity method published previously was used to measure the dynamic response of droplet size and organic phase hold-up in a water-kerosene system. The experiments were performed in a motionless mixer, using Sulzer SMV-4 mixing elements of stainless steel (SS 316) and identical elements coated with a film of Teflon.

A novel concept for a passive solar greenhouse for regions with mild winter climates is described. The concept was tested with a 66-m2 prototype greenhouse. The roof of the greenhouse was made of modular double-layered transparent panels filled with a latent heat-storage material. During both night and day, the thermal performance of the test building was significantly better than that of the control glass house. The main drawback of the proposed method is that the light intensity is low in the morning until the solid Latent Heat Storage Material (LHSM) is completely melted. Therefore, practical application of this method is restricted to specific crops and climate regions.

AbstractThe residence time distribution of poly(vinyl chloride) (PVC) polymers in a counterrotating twin screw commercial extruder was determined and analyzed. The experimental technique involved the use of manganese dioxide as a tracer after being neutron activated and was injected into the extruder during normal operation without interrupting the poly(vinyl chloride) compound production. The experimental results enabled us to better understand the flow and mixing conditions in the extruder.

A new type of passive solar greenhouse, for mild winter climate regions, is presented. The surface of the greenhouse (mainly the roof) is made up of modular, double layer transparent panels filled with latent heat energy storage material (LHSM). This paper describes the concept, its basic material components and the main experimental results which were obtained during several seasons of testing.

A modification of the electroresistivity probe technique of Neal and Bankoff was made allowing its use in liquid-liquid dispersions with drops in the range of 0.2–2 mm diameter. Modifications of hardware and on-line microcomputer signal processing permit the sensor length to be considered, as negligible with respect to the drop size. The principle of operation, the hardware and the validation of the method by independent photographic measurements are presented in this paper. The method has the advantage that hold-up, average drop size and interfacial area can be obtained on-line from a single sensor. The experiments were carried in a 34 in. diameter Sulzer motionless mixer with 15 elements. Both stainless steel 316 (SS316) and Teflon-coated mixing elements were used. The measurements and the data processing were carried out using an Apple microcomputer which was connected on-line to the system through an A/D interface. A fast assembler program was written to achieve high resolution in the signal processing. Steady-state data were obtained by photography and were used to validate the method. The photographic study also allowed the distribution of size in the drop population to be observed. In general, the distribution is Gaussian and the variance of the distribution decreases as the velocity increases. It was found that at low velocities there is a large difference in the average drop diameter in the two kinds of mixer. This suggests that the surface of the mixing elements has an important role in the processes of drop break-up and coalescence.

Phase inversion in liquid-liquid systems flowing in a motionless mixer was studied using the modified electroresistivity method published in Part I of this series (Sembira A., Merchuk J.C. and Wolf D., Chem. Engng Sci. 1986 41 445). The pairs of liquids used were: (a) water-kerosene, (b) water-CCl 4 and (c) water-(kerosene + CCl 4 ). Sulzer SMV-4 mixing elements made of stainless steel (SS316) and identical elements coated with a film of Teflon were used. On the basis of the experimental results, it can be concluded that (a) the metastable or ambivalent zone is very narrow; (b) at low flow rates the nature of the surface of the mixing elements has a strong influence on the phase inversion phenomenon; (c) at high flow rates the nature of the surfaces has a weak influence and the inversion occurs when the volume fraction of the dispersed phase is close to 0.5. A predictive model based on free energy consideration is derived. The model describes the results reported satisfactorily.

A computer simulation program for a central solar domestic heat water (DHW) system has been developed and validated by comparing it with the actual performance data obtained from a real-life system. A computer simulation language, CSMP, was used for the simultaneous solution of the differential equations describing the system. The program was developed from basic principles and defined parameters. It was utilized to study the dynamic behavior of the system and to perform parametric studies to determine the effects of various system parameters on its performance.

A number of years of data on the global irradiation incident on a horizontal surface in Beer Sheva, Israel (lat. = 31°15′N, long. = 34°48′E, elevation ∼ 240 m) have been correlated. It is apparent from these data that this locale possesses a relatively high abundance of sunshine. The average cumulative annual irradiation is 6722MJ/m2 and the average daily irradiation is 18.43 MJ/m2. The percentage frequency of days possessing irradiation rates greater than 20 MJ/m2 is 46 per cent, whereas that possessing less than 10 MJ/m2d is 11.9 per cent. The percentage frequency of cloudy days (KT < 0.34) is low, 7.5 per cent, whereas that for clear days (KT > 0.65) is 29.2 per cent.

A novel approach for calculating the monthly average daily fraction of diffuse radiation has been developed. It is based upon the use of concurrent total solar radiation measurements for both a tilted surface and a horizontal surface. It divides the data into two categories, clear and cloudy day, on an hourly basis. The clear day data is analyzed by means of both Liu and Jordan's and Page's empirical equations. The cloudy day data is analyzed by Liu and Jordan's equation for determining the insolation ratio on a tilted to a horizontal surface. A monthly average value for the diffuse fraction is then determined by calculating a weighted average of the clear and cloudy day values.