Tag Archives: AVS magnetic mill

Activation of Catalysts for Carbon Nanomaterial Production

The most important stage of preparing heterogeneous catalysts for carbon nanomaterial (CNM) is their activation, which is understood as a complex of physical influence on the catalytic material, which allows to significantly increase the efficiency of nanostructure synthesis.

This can be achieved by researching mechanical (dispersion) and physical (electromagnetic and ultrasonic) activation methods.

One of the most important factors defining catalyst efficiency is its granulometric composition. It is known that reduction of the particle size (less than 3 nanometers) causes capsulation inside nanotubes, while increasing it above 25 nanometers leads to uneven size distribution and defects in nanotubes. This is due to the fact the using large catalyst particles (25 to 100 nanometers) prevents carbon scattering from the surfaces where hydrocarbon decay occurs to the surfaces where carbon is deposited; as a consequence, no CNM growth occurs on such particles. Therefore, it is important to define reasonable catalyst particle size, as well as dispersion and classification methods.

Note that dispersion of catalyst microparticles causes both the reduction of size and the changes in the microstructure, e.g. destruction and reduction of pore depth, increasing the boundary of nano-seeds, where graphitized carbon is deposited.

Catalyst was activated in a drum mill and an electromagnetic vortex layer device (AVS). The distinguishing characteristic of the vortex layer in electromagnetic units is the multitude of high frequency and strength shocks, as well as friction, which not only break solid particles, but significantly activate their surfaces due to the deformation of their crystalline lattice. Enormous energy is concentrated in a volume of this process, which direct influence on the material. The influence is so high that it changes the structure as deeply as the atom’s valency shells. The process causes deep changes in the structure of the material.

Mean energy conducted to a volume of the vortex layer reaches 103 kW/m3. This is several orders of magnitude higher than in vibration mills, for instance. Besides, the energy is localized in certain areas, e.g. in the locations where the ferromagnetic particles collide, where mean power reaches even higher.

The electromagnetic vortex layer unit consisted of a process section and a control section, connected by oil tubes and a power cable. The process section consisted of a support, an enclosure, an induction coil for the rotating electromagnetic field, and a detachable operating chamber.

The catalyst activation process was performed with 1…1.5 mm by 10…15 mm PVC encapsulated ferromagnetic particles.

The chamber was loaded with 0.120 kg of the catalyst and 0.060 kg of ferromagnetic particles; retention time varied from 5 to 60 seconds. The granulometric composition of the Ni/MgO catalyst after the dispersion was done by fractionating sieve analysis. The catalyst after activation was separated into fractions and used for CNM synthesis under a unified method of testing various catalyst samples.

The results of the experiment show that the optimal duration time for the finest grinding constitutes 10 seconds, with initial catalyst particle size of 500 micron.

The observed increase of catalyst particle size after 10 or more seconds of dispersion is apparently due to the fact that with time the particles accumulate sufficient energy for spontaneous aggregation.

The analysis of the influence of the catalyst size composition on the mean output of CNM leads to the conclusion: the output increases in inverse proportion to catalyst particle size. This is due to the increased active surface of the catalyst. The experiments demonstrated that the actual method of catalyst dispersion has no significant influence on nanomaterial output.

GlobeCore extends invitation to the International Construction & Utility Equipment Exposition-2019

GlobeCore invites all businesses and parties interested in the implementation of innovative technologies to the International Construction & Utility Equipment Exposition.

This event is biannual, and this year will be hosted by Kentucky Exposition Center, Louisville, Kentucky on 1-3 October. The exhibition focuses, among other things, on electric power transmission and distribution, wastewater treatment, natural gas supply etc.

GlobeCore will be represented in the first two categories by the CMM-G designed to change oil in wind turbine gearboxes and the AVS vortex layer device. You can see these machines and speak with our specialists at booth 2240.

The CMM-G simplifies and accelerates oil change in wind turbines. To protect the new oil from instantly becoming contaminated with impurities left in the gearbox after draining the oil oil, the machine also washes the gearbox with special flushing oil. As for the vortex layer device, it increases the efficiency of the existing wastewater purification systems, reducing process duration and chemical consumption.

Looking forward to meeting you at International Construction & Utility Equipment Exposition-2019!

Industrial Wastewater Treatment

The volume of toxic waste has been growing in recent years, and the environment cannot cope on its own.

Large amounts of contaminants enter the environment with wastewater, including toxic ions of heavy metals. Reagents are used to purify wastewater and decontaminate concentrated solutions (electrolytes etc), neutralizing them and causing sedimentation of heavy metals with an alkaline agent. This method does not allow to achieve the required purity of the water, while generating solid insoluble waste, which is difficult to recycle.

To address the large number of issues related to resource saving and environmental protection from wastewater contamination, is the development of new technologies using compact wastewater treatment systems. In this case the complete treatment of wastewater containing heavy metals is more efficient. Instrument, chemical, engineering and other industries generate a lot of wastewater with heavy metal compounds.

The specific peculiarities of the vortex layer are well suited for treatment of wastewater containing hexavalent chrome and other heavy metals, which allows to significantly reduce the consumption of reagents, improve purification and make the process continuous.

Ferromagnetic particles inside the chamber of the AVS magnetic mill perform intensive stirring of reagents in the chamber. The impacts and friction pulverizes the materials to colloidal particle size. The resulting colloid metal is good reduction agent. At the same time, hydrogen forms due to electrolysis of water in the vortex layer. Both factors have significant impact on hexavalent chrome and other metal reduction. This ability allows to significantly reduce the amount of iron sulfide for chrome reduction and completely reduce chrome by the colloid metal and hydrogen alone.

The process in the AVS magnetic nano-mill lasts only a fraction of second, making the process continuous.

Intensive mixing of reagents and the influence of electromagnetic fields, as well as dispersion of the compounds makes the formed metal hydroxides more finely dispersed than the product of mechanical agitation mixers.

Mechanical devices require large footprint and significant invesment. The duration of the cyclic process while using this method is 30 to 120 minutes.

On the contrary, the AVS magnetic mill unit to remove chrome from wastewater by chemical reduction in alkaline media is equipped only with tanks for iron sulfide and lime milk with portioning pumps, one AVS mill and a filter or a waste collection vessel.