Papers by Keyword: Grindability

Abstract: The carbonate components effect of raw materials - chalk and limestone on the clinker properties has been determined. Studies have been carried out on the raw mix these components partial replacement with the Oskol electrometallurgical plant slag in the amount of 10 and 20%. The maximum decrease in the carbonate component amount was 10%. The grinding clinker individual stages, characterized by the material destruction certain processes have been analyzed. It has been established that by reducing the chalk content in the raw mix and replacing it with the Oskol electrometallurgical plant slag, the clinker grindability is improved. The duration of grinding of such clinker is reduced by 22%. A decrease in the limestone amount in the raw mix and an increase in the Oskol electrometallurgical plant slag content does not affect the synthesized clinkers grindability.

Abstract: End-of-life tyres and elastomer products are recognised by European Union as important valuable resource for circular economy. Current work introduces an analysis of devulcanised crumb rubber comminution technique by means of semi-industrial disintegrator DESI-15. For the estimation of grindability, the main kinematic parameter in the processing of materials was given the specific energy of treatment E_s in kWh/t. Grindability of devulcanised crumb rubber aggregates as a function of particle size of the specific energy of treatment was analysed. Classified devulcanised crumb rubber will be used as a component of composite materials for oil spills remediation and for design of composite materials for civil engineering applications.

Abstract: This article presents the results of the bottom ash from Circulating fluidized Bed Combustion (CFBC). Ashes were modified by grinding in their physical parameters. For this treatment was used the tumbling ball mill at CTU in Prague. In this case were used bottom ashes from Ledvice power plant. Samples of bottom ash were milled in specific amounts and grinding times. The modified samples were tested for the effect of amount of bottom ash in the mill and grinding time on its granulometry. For this testing was used laser diffraction method with particle size analyzer. Milling seems to be great way to get material with better physical and mechanical properties. The reason for this experiment was to better understand behaviour of bottom ash during grinding and made fine filler with specific features for composite building material with high strength.

Abstract: This article presents the results of fly ash from Circulating fluidized Bed Combustion (CFBC) and high temperature fly ash (defined in EN 450-1) with modified physical parameters by grinding. For this treatment was used the mechanical mill. In this case were used two fly ashes. The first sample was from Tisová power plant (CFBC fly ash) and the second one from Počerady power plant (high temperature fly ash). The modified samples were tested for the effect of grinding time on its grindability and granulometry. For testing of samples was used laser diffraction with particle size analyzer and the grindability was determined. The reason for this step was found more stable and better material which achieves better physical and mechanical properties. The first step is mechanical treatment of fly ash’s granule.

Abstract: In this study, the surface grinding was performed at different feed rates and depth of cuts. Grindability of engineering thermoplastics and metals was evaluated. Further, important process parameters influencing surface quality were determined using analysis of variance (ANOVA). Experimental results compared two significantly different groups of materials in order to emphasize common variables. Finally, further research directions were presented to seek for functional relation between process parameters and grindability.

Abstract: The relationship between grindability of blast-hole cuttings, strength parameters and bit wear rate were investigated. In order to achieve this, drill cuttings were collected from twenty blast-holes drilled in a quarry. The samples were tested in the laboratory for Silica content using X-Ray Fluorescence (XRF) spectrometer. Also, the length of button worn on the surface of bit was measured at regular interval with aid of digital vernier caliper on the field as drilling operation progresses to determine wear rate. Sieve analysis was used to determine the size distribution of the blast hole cuttings in the laboratory using sieve shaker while grindability was determined using the ball mill, by grinding for certain number of revolutions. The result obtained show that the weight of drill cuttings retained on 850μm decreases while weight retained on 75μm increases as wear rate increases. Grindability was correlated with wear rate and weight retained at 75μm sieve, the value of multiple coefficients of correlation is 0.126 and 0.064 respectively, this show that there is no relationship between grindability, wear rate and weight of cuttings retained on 75μm. The result of correlation of wear rate and weight retained at 75μm shows that strong relationship exist between them and the value of multiple coefficient of correlation is 0.892.

Abstract: A new comprehensive evaluation method for grindability of ceramic materials is advanced. The mechanical property parameters of ceramic materials are selected as influencing factors for grindability, the interval sample matrices are established, the interval grey relational coefficient matrices are calculated and the factors weights determined by the eigenvectors. The important degree sequence of influencing factors and comprehensive evaluation value of grindability for ceramic materials are obtained. Seven typical engineering ceramic materials are analyzed using the method, the objective and comprehensive results are gained.

Abstract: A Stiff Air Layer, Formed around a Rotating Grinding Wheel, Tends to Restrict Grinding Fluid Penetrate Deep inside the Grinding Zone. for this, much Fluid Is Wasted, and Thermal Defects in Grinding May Not Be Controlled. in the Present Experimental Work, a Flood Cooling System with Pneumatic Barrier Is Used for Delivering Grinding Fluid. the Pneumatic Barrier Breaks the Stiff Air Layer, and Therefore, Grinding Fluid Reaches Grinding Zone. an Exotic Nickel Base Alloy, Inconel 600, Is Taken for Surface Grinding Experiments Using an Infeed of 30 µm under Different Environmental Conditions. the Effect of Different Experimental Conditions Is Investigated in Respect of Grinding Force, Chip Formation, Surface Quality and Wheel Condition. the Experimental Result Shows that Grinding Forces and Wheel Wear Are Remarkably Reduced, and Favourable Chips and Good Surface Quality Are Obtained with the Use of Flood Cooling along with Pneumatic Barrier Setup Compared to other Environmental Conditions.

Abstract: The current paper deals with characterization of TiC−NiMo cermet powders produced by mechanical milling technology. TiC-based cermets scrap was processed by semi-industrial and laboratory disintegrator milling system. Chemical composition, shape and size of produced powders were analyzed. To estimate the properties of recycled cermet powders the sieving analysis, and angularity studies were conducted. The grindability was estimated using specific energy parameter (Es). Considering that viewpoint, the study is focused on angularity studies as the shape of spray powder has considerable influence on spraying efficiency, the quality and reliability of the coating. To describe the angularity of milled powders, spike parameter – quadratic fit (SPQ) was used and experiments for determination of SPQ sensitivity and precision to characterize particles angularity were performed. Uncertainty of measurements demonstrated trustworthiness of results. The standard deviation of SPQ regardless of milling cycles is the same. For use of produced powders as reinforcements in sprayed coatings the technological parameters of powders were studied. Perspective future use of powders as reinforcements in composite coatings as well as abrasives in tooling were demonstrated.

Abstract: The scale of influence of the single crystal sapphire crystallographic plane orientation and grinding conditions on the material removal rate, surface finish and the state of sub-surface layer have been studied under Low-Temperature Precision Grinding (LPG). The schemes of forming partial spherical heads for human hip joints endoprostheses are considered and elaborated. The possible versions of forming the spherical heads of endoprosthesis based on the novelties in kinematics and the mode of material removal are discussed.