Design of the Particle Size Composition of an Alumina Powder Matrix for Maximum Flowability and Minimum Water Content

2006 ◽  
Vol 530-531 ◽  
pp. 425-430 ◽  
Author(s):  
Abílio P. Silva ◽  
Ana M. Segadães ◽  
Tessaleno C. Devezas
Keyword(s):  
Particle Size ◽  
Water Content ◽  
Raw Materials ◽  
Size Composition ◽  
Statistical Modelling ◽  
Linear Shrinkage ◽  
Response Surfaces ◽  
Alumina Powder ◽  
Particle Size Composition ◽  
The Matrix

In this work, commercial alumina fine powders were used as raw materials, namely two tabular alumina fractions (–500 mesh and –230 mesh) and a reactive alumina. Statistical modelling and the Response Surface Methodology (Statistica, Mixtures Designs and Triangular Surfaces module) were applied to three-component mixtures and used to calculate the various property-composition surfaces. To that aim, the various mixtures were prepared, cast, dried, fired and characterised. The particle size distribution modulus, q, was determined for all mixtures using the software LISA. The various response surfaces were then combined, so that the water content in the mixture could be minimised and the matrix flowability maximised. The properties of the resulting test-bricks (linear shrinkage, mechanical strength, apparent density and porosity) were also modelled and response surfaces were obtained. Combined results enabled the definition of an optimised particle size composition range, which guarantees the presence of a low water flow-bed that enables the aggregate self-flow.

Statistical Modelling of the Particle Size Composition of an Alumina Matrix for No-Cement Self-Flowing Refractory Castables

2006 ◽  
Vol 514-516 ◽  
pp. 604-608 ◽  
Author(s):  
Abílio P. Silva ◽  
Ana M. Segadães ◽  
Tessaleno C. Devezas
Keyword(s):  
Particle Size ◽  
Water Content ◽  
Raw Materials ◽  
Size Composition ◽  
Statistical Modelling ◽  
Matrix Composition ◽  
Mechanical Resistance ◽  
Particle Size Composition ◽  
Refractory Castables ◽  
System Properties

In the processing of any particulate system (including refractory castables), the finer sized particle fraction (matrix or filler) is mostly responsible for the final system properties. Alumina fine powders were used in this work as raw materials, namely two tabular alumina fractions (–500 mesh and –230 mesh) and a commercial reactive alumina. Statistical modelling and the Response Surface Methodology (Statistica, Mixtures Designs and Triangular Surfaces module) were used to optimise the particle size composition of the three-component mixtures leading to matrix maximum flowability. The mixing methodology, aimed at minimising the water content, was kept constant. No-cement alumina castables produced with the various fine size powder mixtures, were used to prepare test-pieces. After drying and sintering, their mechanical resistance (MoR), density, porosity, water absorption, thermal shock behaviour and microstructure were evaluated. The results obtained evidenced the relevance of variables such as the water content per unit specific surface area, needed to reach the self-flow “turning point”, and validated the statistical optimisation method used. Moreover those results showed the existence of a matrix composition range, which favours the formation of a flow-bed that enables the aggregate self-flow.

scholarly journals The effect of liquid pig manure on the wheat yield, content and balance of nutrients in light-gray forest soil with light particle-size composition

2019 ◽  
Vol 20 (5) ◽  
pp. 456-466
Author(s):  
V. I. Titova ◽  
L. D. Varlamova ◽  
R. N. Rybin ◽  
T. V. Andronova
Keyword(s):  
Particle Size ◽  
Spring Wheat ◽  
Wheat Yield ◽  
Size Composition ◽  
Light Particle ◽  
Pig Manure ◽  
Wheat Crop ◽  
Dry Matter Content ◽  
Particle Size Composition ◽  
Positive Balance

The research has been carried out under production conditions on light gray forest soils with light particle-size composition at an area of 550 hectares where liquid pig manure (LPM) of a large pig breeding complex is annually used as an organic fertilizer at doses of 60 and 90 t/ha. The average characteristics of LPM are as follows: dry matter content is 9.5%, pH 7.7 units, nitrogen 0.22%, phosphorus 0.11%, and potassium 0.12%. The cultivated grain crops were presented by winter and spring wheat varieties, Moskovskaya 39 and Esther, respectively. It has been established that at the dose of 60 t/ha LPM for two years of research at an average a mean wheat yield was 3.0-3.75 t/ha, and at the dose of 90 t/ha - up to 4.75 t/ha. The return on investments for fertilizers in the “winter wheat → spring wheat” crop rotation link at the dose of 60 t/ha of LPM was 5.41 kg of grain per 1 kg of active substance of manure, at the dose of 90 t/ha - 4.57 kg / kg. A positive balance of nutritional elements developed on all fields, but it was better balanced when the dose of LPM was 60 t/ha and the yield was 3.0 t/ha of grain annually, or when the LPM dose was 90 t/ha and the yield of wheat was 4.75 t/ha. In this case, the estimated potassi-um supply of soil occurs at a lower rate than that of nitrogen and phosphorus. The application of 120 t of LPM during two years in total on loamy sand and of 180 t/ha on light loamy soil provided an increase in the content of mobile phosphorus compounds by 5-22 mg/kg, and potassium - by 11-30 mg/kg with a variation coefficient of 28-57% and 21-49%, respectively.

scholarly journals Determination of soil grain size composition by measuring apparent weight of float submerged in suspension

2017 ◽  
Vol 31 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Jarosław Kaszubkiewicz ◽  
Witold Wilczewski ◽  
Tibor József Novák ◽  
Przemysław Woźniczka ◽  
Krzysztof Faliński ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Composition ◽  
Digital Transmission ◽  
Weight Changes ◽  
Laser Method ◽  
Particle Size Composition ◽  
Apparent Weight ◽  
High Level ◽  
The Stokes Equation

AbstractTexture is one of the most significant physical properties of soils. Over the years, several methods of its measuring were developed. The paper presents a method for determining the particle size composition of soils, based on the separation of particles in the sedimentation process. Density of suspension is determined on the basis of apparent weight changes of a float submerged in it. The weight of the float suspended on a thin line, at a given depth in the suspension, is measured with a sensitive piezoelectric dynamometer. The Stokes equation is used to calculate the content of soil fractions with equivalent diameters in the range of 0.001 to 0.1 mm. Digital transmission of results from the dynamometer, the temperature sensor and measurements of the distance defining the depth of immersion of the float to the computer enable calculations of particle size composition to be performed automatically. This paper presents the results of measurements of the particle size composition of artificially generated mixtures of ‘silt’ and ‘clay’. The results are compared with results obtained with other methods (including the laser method). A high level of repeatability of the results and satisfactory compatibility in relation to the reference pipette method are noted.

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