Application of Magnetic and Ultrasonic Methods for Determining Parameters of Ferromagnetic Components in Iron Ore Slurry Flows

The article considers the method for controlling the ferromagnetic component content in slurry flow by ultrasonic and magnetic measurements. One of the basic factors determining the efficiency of magnetic separators at iron ore concentration plants is the quality of distribution of the ground ore into the product containing the ferromagnetic component and the waste rock. Due to the fact that in most cases, magnetic separators extract minerals with strongly magnetic properties, it is essential to find the magnetic component content in the input ore and products of its distribution in order to improve control over the technological process. Currently, low accuracy and reliability make existing means of operative control over the ferromagnetic component content in the slurry flow inefficient. Density of slurry is one of the primary disturbing factors affecting the accuracy of measurements, and this fact determines the necessity of measuring this parameter while controlling the ferromagnetic component content. Combined methods of measurements are a promising trend in designing sensors of useful component content in the slurry flow. The article describes the method for controlling the ferromagnetic component content in slurry flow by ultrasonic and magnetic measurements.

Optimization of the centrifugal slurry pump through the splitter blades position

Optimal transfer of two-phase solid-liquid flow (slurry flow) has long been a major industrial challenge. Slurry pumps are among the most common types of centrifugal pumps used to deal with this transfer issue. The approach of improving slurry pumps and consequently increasing the efficiency of a flow transmission system requires overcoming the effects of slurry flow such as the reduction in head, efficiency, and wear. This study attempts to investigate the changes in the pump head by modifying the slip factor distribution in the impeller channel. For this purpose, the effect of splitter blades on slip factor distribution to improve the pump head was investigated using numerical simulation tools and validated based on experimental test data. Next, an optimization process was used to determine the characteristics of the splitter (i.e., length, number, and environmental position of the splitter) based on a combination of experimental design methods, surface response, and genetic algorithm. The optimization results indicate that the splitters were in a relative circumferential position of 67.2% to the suction surface of the main blade. Also, the optimal number and length of splitter blades were 6 and 62.8% of the length of the main blades, respectively. Because of adding splitter blades and the reduction in the flow passage, the best efficiency point (BEP) of the slurry pump moved toward lower flow rates. The result of splitter optimization was the increase in pump head from 29.7 m to 31.7 m and the upkeep of efficiency in the initial values.

Study on Nanoparticle Agglomeration During Chemical Mechanical Polishing (CMP) Performance

The materials used in base fluids and nanoparticles are varied. One- and two-step manufacturing processes are used to create stable and highly conductive nanofluids. Both methods for making nanoparticle suspensions suffer from nanoparticle agglomeration, which is a major problem in any technique that uses nanopowders. As a result, the key to substantial surface finishing at planarization treatments and increase in the thermal characteristics of nanofluids is the production and suspension of almost non-agglomerated or monodispersed nanoparticles in liquids. This unfavorable aggregation is a major problem in nanopowder technology. Primary material constituents agglomerate rapidly overcoming the stable situation, and nanoparticle agglomerates set out in liquids, making it difficult to create nanofluids using two-step techniques. This research looks at the link between nanoparticle agglomeration during slurry flow and Material Removal Rate (MRR) during chemical mechanical polishing (CMP). The reciprocal relationship between MRR and the shear force exerted by the slurry flow was qualitatively elucidated by the researchers for the theoretical investigation. However, the present manipulation is focused on quantifying the shear stress exerted by nanoparticles floating in the slurry. As a result, the MRR-aggregation model is established based on the relationship between MRR and shear force. The experiment is being carried out to support this idea. The experimental results of aggregation and shear forces have been conducted by some recent studies. However, the extension to the real CMP is very promising for accomplishing a precise style of the removal mechanism and surface finishing criterion as well.

Numerical Modelling of Heat Transfer in Fine Dispersive Slurry Flow

Slurry flows commonly appear in the transport of minerals from a mine to the processing site or from the deep ocean to the surface level. The process of heat transfer in solid–liquid flow is especially important for the long pipeline distance. The paper is focused on the numerical modelling and simulation of heat transfer in a fine dispersive slurry, which exhibits yield stress and damping of turbulence. The Bingham rheological model and the apparent viscosity concept were applied. The physical model was formulated and then the mathematical model, which constitutes conservative equations based on the time average approach for mass, momentum, and internal energy. The slurry flow in a pipeline is turbulent and fully developed hydrodynamically and thermally. The closure problem was solved by taking into account the Boussinesque hypothesis and a suitable turbulence model, which includes the influence of the yield shear stress on the wall damping function. The objective of the paper is to develop a new correlation of the Nusselt number for turbulent flow of fine dispersive slurry that exhibits yield stress and damping of turbulence. Simulations were performed for turbulent slurry flow, for solid volume concentrations 10%, 20%, 30%, and for water. The mathematical model for heat transfer of the carrier liquid flow has been validated. The study confirmed that the slurry velocity profiles are substantially different from those of the carrier liquid and have a significant effect on the heat transfer process. The highest rate of decrease in the Nusselt number is for low solid concentrations, while for C > 10% the decrease in the Nusselt number is gradual. A new correlation for the Nusselt number is proposed, which includes the Reynolds and Prandtl numbers, the dimensionless yield shear stress, and solid concentration. The new Nusselt number is in good agreement with the numerical predictions and the highest relative error was obtained for C = 10% and Nu = 44.3 and is equal to −12%. Results of the simulations are discussed. Conclusions and recommendations for further research are formulated.