ADSORPTION OF OBSOLETE SLUDGE, PEAT, BUCKWHEAT HUSKS AND COMPOSITIONS FROM THEM

The problem of accumulation of obsolete silt deposits at aeration stations is relevant for the whole territory of Ukraine. This can lead to environmental hazards. Therefore, the task of processing silt deposits with the creation of granules based on them with the addition of peat and buckwheat husks. Van Bamelen's tensometric (static) method was used to determine the equilibrium humidity of the experimental samples depending on the relative humidity . As a result of researches kinetic curves of adsorption over obsolete silt deposits, peat, buckwheat husk and the three-component composition created on their basis are received. Kinetic adsorption curves indicate a slow process. The adsorption curves of the three-component composition have the character of curves of obsolete sludge, which have a non-uniform character. The obtained equilibrium humidity does not exceed the standard humidity for fuel pellets. The adsorption isotrams of the three-component composition and its components are determined, from which the equations of experimental and linearized isotrams are obtained. The analysis of experimental isotherms allows to relate them relatively to the isotherms of adsorption IV, which are observed in inorganic oxides and in other porous bodies. For the first time, the adsorption properties of three-component compositions based on peat, sludge and buckwheat husk were studied. The obtained equilibrium humidity of the compositions does not exceed the standard humidity for fuel pellets (is 20%) and is 6 - 7%. Therefore, they can be used for combustion in biomass boilers. The resulting ash can be used for the production of bricks, cement and other building materials. During storage of composite granules in order to prevent loss of their technological properties, it is recommended to maintain humidity at the level of 60 - 70%.

Reliability and Durability Enhancement of Large-area Mullite-cordierite Composite Substrates for Semiconductor Probe Card

Spherical mullite (M)-cordierite (C) composite granules were prepared by spray drying the fine starting powders obtained from attrition milling to produce sintered mullite-cordierite composite pellets with a dense structure. The effects of attrition milling on the morphology, size and size distribution of the formed composite granules were investigated. The results showed that the milled starting powders formed the spherical granules with homogeneous size distribution. The composition ratio (M:C = 100:0, M:C = 90:10, M:C = 70:30, M:C = 50:50, M:C = 30:70, M:C = 0:100) and sintering temperature (1300–1450℃) were optimized to fabricate the sintered mullite-cordierite composite pellets with low thermal expansion coefficients (TECs) and excellent mechanical properties. Samples of 70 wt% mullite-30 wt% cordierite sintered at 1350℃ exhibited excellent bulk density, porosity, TEC, and flexural strength. Based on these results, a large-area mullite-cordierite composite substrate was fabricated for application in semiconductor probe card. The changes in sheet resistance and flexural strength were measured to study the influence of the environmental tests, including high temperature storage test, damp heat test, and thermal shock test, on the large-area substrate. A low rate of change in sheet resistance and flexural strength was observed. After the environmental tests, the sheet resistance and flexural strength were confirmed to be within 10% of their values prior to the tests. These results show that the fabricated mullite-cordierite composite exhibits high reliability and durability and is a suitable for semiconductor probe cards.

Porous Composite Granules with Potential Function of Bone Substitute and Simvastatin Releasing System: A Preliminary Study

In this work, 3D porous granules based on Zn and Se-containing calcium phosphates (CaPs) were fabricated using a droplet-extrusion technique. The composite beads varied in composition and contained two different natural polymers: sodium alginate (SA) and gelatin (GEL). To analyse and compare their physicochemical properties, such as porosity and morphology, different techniques were applied, including scanning electron microscopy (SEM), sorption of N2 and mercury porosimetry. Prior to the fabrication of the granules, the properties of CaPs materials, (the bioceramic base of the beads), selenium (IV)-substituted hydroxyapatite (Se-HA) and zinc-substituted dicalcium phosphate dihydrate (Zn-DCPD), were also investigated. The results of cell viability assessment showed that Se-HA powder was non-toxic to human osteoblasts (hFOB 1.19) and simultaneously exhibited high toxicity to tumour cells (Saos-2). Once the cytotoxicity assay was completed, Se-HA and Zn-DCPD were used to prepare 3D materials. The prepared porous granules were used as matrices to deliver simvastatin to bones. Simvastatin was applied in either the lipophilic form or hydrophilic form. The release kinetics of simvastatin from granules of different composition was then assessed and compared.

Fabrication of transparent spinel by the reactive spark plasma sintering of spray-dried Magnesia-Alumina nanocomposite without sintering aid

In this project, magnesia-alumina composite granules were prepared using spray drying method. Next, the synthesized powder was sintered at 1400°C for 15 min under 100 MPa pressure through spark plasma sintering without using any sintering aid. The effect of two sintering temperatures of 1400 °C and 1500 °C was explored on the phase formation, density, fracture toughness, and optical transmission within visible and IR ranges. SEM results indicated that the magnesia-alumina composite granules had spherical morphology with the mean particle size of 21 micrometers. The XRD pattern showed that after the spark plasma sintering stage at 1400 °C and 1500 °C, the spinel phase of magnesium aluminate was obtained as in situ. The disc sintered at 1400 °C had greater maximum transmission compared to the samples sintered at 1500 °C (47% vs. ~70%) within the middle IR region because of lower porosity of the sample. The magnesium aluminate spinel sintered at 1400 °C had a density 99.98% of the theoretical density, hardness 18 GPa, and fracture toughness 1.6 MPam1/2.

On the structure and properties of functional coatings from composite powders of the aluminum – silicon nitride system reinforced with a SiALON type phase

The work studies development process of a composite powder of the aluminum – silicon nitride system and sprayed coatings using the mechanism of the formation of composite granules and the distribution of a hardening phase of the Sialon type in them. Various modes of powder composite mechanosynthesis are studied. The results of determining the hardness, chemical composition and distribution of elements in the resulting coating are given.

The Study of the Preliminary Forming Process of the Highly-Homogeneous Mixture Consisting of the Aluminum Powder – CNT in the Production Technology of Composite Materials

The issue of the nanocomposites’ synthesis using of aluminum matrixes, reinforced with carbon nanotubes, with high physical and mechanical performance capabilities, as related to achieving of the homogeneous dispersion of carbon nanotubes in the composite’s aluminum matrix has been considered. Basics of the preparation technology have been developed and requirements for parameters of the so-called «normalized» mixture (highly-homogeneous in terms of volume of the dry mixture «aluminum powder – single-walled carbon nanotubes), intended for the efficient synthesis of composite granules by the mechanical alloying have been determined.

Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite Granule Composts from Hazardous Sludges and Industrial Waste Slurries

There is a great concern about surface water pollution with high level mercury, lead (Pb) over 10 mg/l, 30 mg/l to the fishing lakes and streams in Şırnak Province even contaminating fresh water fishing and poisonening of human by merury and lead in thr region. The chromium over 50 mg/l from industrial seepages was disposed to lakes and streams in our country. There is a great green concern prompting land in order to control acidic mine waters so that the research study controlled and avoided hazardous metal limits of residual stream contaminants of heavy metals by sorption local clay and zeolite compost. The contamination rate changes to those based on seepage concentrations and wetness. The stream amendments, such as shale char carbonized from Şırnak asphaltite containing 52–60% shale activated by acid washing under microwave radiation as geo material composted for waste water treatment should control contaminated effluents concentration. The field studies to evaluate the stability of heavy metal concentrations and salts were scarce. The initial objective of this study was to determine the effects of seepage flow to surface and groundwater from the industrial discharge. In this study, important investigations have been made on composite granules production with Şırnak shale char and zeolite feed in order to activated in microwave oven 2 M HCl dissolution. The compost sorbent for high level heavy metal sorption in laboratory water packed bed column adsorption compost system. However, the results of filled packed bed zeolite yield high metal transfer to compost. Due to the complex chemistry of shale pores, and high porosity, heat conduction improved in the microwave sorption depended on granule size decreased. The other heavy metal sorption distribution was changed in the activation dependent on the microwave heating power.

CREATION OF GRANULAR COMPOSITE MATERIALS WITH MULTILAYER STRUCTURE

Granular products are widely used in many industries for the production of catalysts in oil refining and organic synthesis, drugs, food products, fertilizer production, etc. The main advantages of granular products are ease of operation and storage. Depending on the morphological structure, the granules obtained as a result of the technological process are divided into one-component, single-layer, composite-coated granule, multilayer granule, frame granule, and combinations thereof. In this paper, we consider, as an example, the technological basis of granulation of aqueous solutions of ammonium sulfate with impurities of humates, calcium carbonate and other substances with the formation of multilayer composite granules in a fluidized bed granulator. The processes of dehydration and mass crystallization during granulation, namely the influence of the drying rate and impurities on the kinetics of the evaporation process of the dispersed heterogeneous solution on solid particles have been studied. In the process of mass crystallization, when the saturation concentration is reached by removing the solvent, the processes of nucleation and crystal growth occur with the formation of a crystalline framework of ammonium sulfate crystals between, which impurities of organic matter and other components are evenly distributed in the volume of the formed micro layer. It was confirmed that the obtained granules of the composite granular fertilizer have a composite multilayer structure with a uniform distribution of suspended particles in the volume of the granule. Bibl. 14, Fig. 4.