scholarly journals Particle Size Effects on Selectivity in Confined Bed Comminution

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 342
Author(s):  
Holger Lieberwirth ◽  
Lisa Kühnel
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Effects ◽  
Experimental Investigations ◽  
Ore Processing ◽  
Tumbling Mills ◽  
Particle Bed ◽  
Vertical Roller

Confined bed comminution in high-pressure grinding rollers (HPGRs) and vertical roller mills (VRMs) was previously used preferably for grinding comparably homogeneous materials such as coal or clinker. Meanwhile, it started to complement or even replace tumbling mills in ore beneficiation with ore and gangue particles of rather different breakage behaviors. The selectivity in the comminution of a mixture of particles with different strengths but similar particle size distribution (PSD) of the constituents in a particle bed was investigated earlier. The strength of a material is, however, also a function of particle size. Finer particles tend to be more competent than coarser ones of the same material. In industrial ore processing using confined bed comminution, this effect cannot be neglected but even be exploited to increase efficiency. This paper presents research results on this topic based on experimental investigations with model materials and with natural particles, which were stressed in a piston–die press. It appeared that the comminution result substantially depends on the material characteristics, the composition of the mixture and the PSD of the constituents. Conclusions will be drawn for the future applications of selective comminution in mineral processing.

Modelling the Effect of Processing Parameters of Continuous Flow High Pressure Throttling System and Microfluidizer on Particle Size Distribution of Soymilk

2013 ◽  
Vol 9 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Litha Sivanandan ◽  
Romeo T. Toledo ◽  
Rakesh K. Singh
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Temperature Rise ◽  
Continuous Flow ◽  
Volume Fraction ◽  
Emulsion Stability ◽  
Processing Parameters ◽  
Flow Rates

AbstractTexture, appearance, and emulsion stability of soymilk are affected by the size and distribution of suspended particles. To produce soymilk which contains all solids in the soy, whole dehulled beans were used in the study. A microfluidizer with throttling valve attachment was used to study the influence of various pressure levels on the particle size distribution of soymilk. Soymilk was processed with a continuous flow high pressure throttling (CFHPT) system to study the effects of different pressures and flow rates in the temperature rise and particle size distribution of soymilk. The results showed that there existed a significant effect of flow rate through the CFHPT on the particle size suspended in soymilk. Temperature rise was proportional to increase in pressure of the CFHPT system. Significant decrease in particle size of soymilk was obtained by increasing pressure for both CFHPT and microfluidizer. Empirical models were established between the pressure applied, volume fraction of particle size, and particle size diameter obtained for soymilk in each system.

Approach for correcting particle size distribution measured by optical particle counter in high-pressure gas pipes

2018 ◽  
Vol 57 (13) ◽  
pp. 3497 ◽  
Author(s):  
Lifeng Lu ◽  
Xiaolin Wu ◽  
Zhongli Ji ◽  
Zhiyi Xiong ◽  
Mingxing Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Counter ◽  
Optical Particle Counter

scholarly journals Moment Dynamics of Zirconia Particle Formation for Optimizing Particle Size Distribution

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 333
Author(s):  
Wolfgang Halter ◽  
Rahel Eisele ◽  
Dirk Rothenstein ◽  
Joachim Bill ◽  
Frank Allgöwer
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Process Parameters ◽  
Formation Process ◽  
Particle Growth ◽  
Particle Formation ◽  
Zirconia Particle ◽  
Experimental Investigations ◽  
Particle Agglomeration

We study the particle formation process of Zirconia ( ZrO 2 )-based material. With a model-based description of the particle formation process we aim for identifying the main growth mechanisms for different process parameters. After the introduction of a population balance based mathematical model, we derive the moment dynamics of the particle size distribution and compare the model to experimental data. From the fitted model we conclude that growth by molecular addition of Zr-tetramers or Zr-oligomers to growing particles as well as size-independent particle agglomeration takes place. For the purpose of depositing zirconia-based material (ZrbM) on a substrate, we determine the optimal process parameters such that the mineralization solution contains preferably a large number of nanoscaled particles leading to a fast and effective deposition on the substrate. Besides the deposition of homogeneous films, this also enables mineralization of nanostructured templates in a bioinspired mineralization process. The developed model is also transferable to other mineralization systems where particle growth occurs through addition of small molecular species or particle agglomeration. This offers the possibility for a fast determination of process parameters leading to an efficient film formation without carrying out extensive experimental investigations.

scholarly journals An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores

Minerals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 483 ◽  
Author(s):  
Hernan Anticoi ◽  
Eduard Guasch ◽  
Sarbast Ahmad Hamid ◽  
Josep Oliva ◽  
Pura Alfonso ◽  
...  
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Distribution Function ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Single Particle ◽  
Pressing Force ◽  
Product Particle ◽  
Compression Condition ◽  
Roll Crusher

An improved approach is presented to model the product particle size distribution resulting from grinding in high-pressure roll crusher with the aim to be used in standard high-pressure grinding rolls (HPGR). This approach uses different breakage distribution function parameter values for a single particle compression condition and a bed compression condition. Two materials were used for the experiments; altered Ta-bearing granite and a calc-silicate tungsten ore. A set of experiments was performed with constant operative conditions, while varying a selected condition to study the influence of the equipment set-up on the model. The material was comminuted using a previously determined specific pressing force, varying the feed particle size, roll speed and the static gap. A fourth group of experiments were performed varying the specific pressing force. Experimental results show the high performance of the comminution in a high-pressure environment. The static gap was the key in order to control the product particle size. A mathematical approach to predict the product particle size distribution is presented and it showed a good fit when compared to experimental data. This is the case when a narrow particle size fraction feed is used, but the fit became remarkably good with a multi-size feed distribution. However, when varying the specific pressing force in the case of the calc-silicate material, the results were not completely accurate. The hypothesis of simultaneous single particle compression and bed compression for different size ranges and with different parameters of the distribution function was probed and reinforced by various simulations that exchanged bed compression parameters over the single particle compression distribution function, and vice versa.

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