Correlation Between Granule Strength and Green Strength at Compaction of Cemented Carbide Powder Materials

The correlation between granule strength and green strength of hard metal powders is examined. The approach is based on experiments and numerics. In the latter case, a Design of Experiment software is used. The granule strength of the powder (particle) is determined by GFP-measurements (“Granularfestigkeits-Prüfsystem”). During this test, a single particle is pressed from one side until breakage. The corresponding measurements of the green strength are done using three-point bend (3PB) testing. The experimental results show that the pressing agent has a strong influence on the behavior of both quantities. The statistical evaluation shows that the relation between the two strength properties is very close to linear with coefficient of determination R2 taking on the value 0.97. This of course indicates that it is possible to get information about one of the properties for a similar set of materials by experimentally determining the other one. This is of substantial practical importance as for one thing it can limit the amount of testing required. Even though the present investigation is pertinent to hard metal powders, the results could be of value for many other types of powder materials.

PRODUCTION OF LIME-AMMONIUM NITRATE BASED ON CHALK, NITRATE AND AMMONIUM SULFATE

The article studies the process of obtaining carbonate-ammonium nitrate (CAN) based on the mixing of melt ammonium nitrate (NH4NO3) with chalk (СаСО3) and ammonium sulfate (NH4)2SO4). For the granulation of nitrate-sulfate-carbonate melt the prilling method is applied using a granulation tower. Determined the composition and properties of new types of fertilizers. It is shown that with the ratio NH4NO3 : СаСО3 : (NH4)2SO4 = 100 : 24 : 1 the product contains 28,03% N, SO3 – 0,50%, 10% СаО and has a granule strength of 6,03 MPa, which is much higher than the strength of pure NH4NO3 granules (1,32 MPa). Porosity and absorption of pure AN granules is 22,0% and 4,82 g. With an increase in the proportion of chalk and ammonium sulfate to the NH4NO3 : СаСО3 : (NH4)2SO4 = 100 : 24 : 1 ratio, the porosity and absorbency of the LAN granules is 6,11% and 2,57g, respectively. It was revealed that the use of the (NH4)2SO4, СаСО3 additive in the NH4NO3 melt at a mass ratio of NH4NO3 : СаСО3 : (NH4)2SO4 = from 100 : 2 : 0,5 to 100 : 58 : 2 allows to increase the strength and temperature of the onset of decomposition of the nitrate granules by 2-6,7 and 1-1,3 times and reduce the porosity by 2,7-4,8 2 times.

Physico-chemical properties lime-ammonium nitrate based on chalk, nitrate and ammonium sulphate

For the granulation of nitrate-sulfate-carbonate melt, the prilling method is applied using a granulation tower. The composition and properties of new types of fertilizers were studied. It is shown that with the ratio NH4NO3: СаСО3: (NH4)2SO4 = 100: 24: 1 the product contains 28,03% - N, 0,50% - SO3, 10% - СаО and has a granule strength of 6.03 MPa, which is much higher than the strength of pure NH4NO3 granules (1.32 MPa). The absorption of pure AN granules is 4.82 g. With an increase in the proportion of chalk and ammonium sulfate to the NH4NO3: СаСО3: (NH4)2SO4 = 100: 24: 1 ratio, the absorbency of the LAN granules is 2.57g.

The Opportunities of Sustainable Biomass Ashes and Poultry Manure Recycling for Granulated Fertilizers

A need for the disposal of poultry manure and the reduction of its impact on the environment encourages the search for cleaner and more efficient ways to utilize and recycle production waste. It is known that granulated ash and manure are the most effective alternatives for ash and manure recycling, as compared to the unprocessed product. This paper presents an investigation of ash and poultry manure recycling for granulated fertilizers. Accepted standard experimental methods were used. The physical and mechanical characteristics of the granules, elemental composition ratio, and the process of compression of the raw material mill were determined experimentally. This research shows that, when a higher ash concentration was determined, the initial bulk density was larger and the density and pressure in the granulation process increases faster. The content of ash in the raw material increased granule strength; however, when increasing the ash mass in the raw material from 25% to 50%, energy consumption increased from 6.59 kJ·kg−1 to 17.72 kJ·kg−1. The process of compression of the raw material mill was obtained in two stages. In the first stage of compression, the mass density varied from 3–11 kg·m−3 and the pressure varied from 1.25–8.27 MPa. In the second pressure stage, the mass deformation was elastic and the pressure process was described by indicator functions.

Influence of Wood Flour Additive on Porous Structure and Strength Properties of Moulded Alumina

The moulded Al2O3 materials prepared by mixing of thermochemically activated aluminum trihydroxide (TCA ATH) with wood flour were proposed to be used as promising porous catalyst support for various processes. A series of Al2O3 supports with different wood flour loading (0, 2 and 5 %wt.) were studied by SEM, low-temperature N2 sorption, XRD, granule strength and water-absorbing capacity. It was shown that supports were characterized by porous structure with mesopore sizes of 2-20 nm and specific surface area of 159-186 m2/g. The increase of the amount of wood flour leads to increase of the share of pore volume with wider than 10 nm and the decrease of the strength of alumina granules. Thus, optimization of preparation conditions allows obtaining alumina materials with desired porous structure.