A Study On Ultra Fine Grinding Of Silica And Talc In Opposed Fluidized Bed Jet Mill [TJ1345. S187 2008 f rb].

Fine grinding is normally carried out in energy intensive grinding mills such as jet mill. Besides size reduction, jet mill also induced mechanochemical effect on the ground product. Proses pengisaran halus biasanya dilakukan di dalam pengisar intensif tenaga seperti pengisar jet. Selain daripada pengurangan saiz, pengisar jet juga meghasilkan kesan mekanokimia terhadap partikel yang dikisar

Properties of Calcium Carbonate/Mica and Calcium Farbonate/Talc Filled Polypropylene Composites

Mineral fillers namely talc, calcium carbonate, mica, glass and carbon fibres are common fillers used in plastic industry that can alter thermoplastic properties. With the incorporation of fillers, significant outcome can be observed especially in the mechanical properties of polymer composites produced apart from its rigidity and resistance to temperature. Properties of single and hybrid fillers filled polypropylene (PP) composites were studied in this research work. Mineral fillers such as talc, mica and calcium carbonate (CaCO3) were incorporated into PP composites. Realising the advantage of each mineral filler and the effect of hybrid fillers, CaCO3/Talc (CC/T) and CaCO3/Mica (CC/M) at 40 wt% were investigated. Generally, the results demonstrated that CC/M has higher tensile modulus than CC/T and both hybrids composites did not give significant effect on the tensile strength. Thermogravimetric analysis (TGA) results revealed that CC/M increased thermal stability of PP composites when compared to CC/T. Flammability testing on PP hybrid composites was carried out where lower burning rate indicates better flammability. From the results, it shows that CC/M system have better flammability compared to CC/T system

Development Of Nanocrysta Lite Cati03 Via High Intensity Grinding Using Value Added Local Raw Materials.

Mechanochemical synthesis of calcium titanate, CaTi03 was carried out in planetary mill by varying the milling time and mill rotational speed at three levels. CaC03 and Ti02 (anatase) was used as starting materials

Changes in the structure of talc by continuous jet milling in relation to imposed specific kinetic energy

Ultra fine talc is used in many industries such as paper, paints, polymers, cosmetics and pharmaceutical. Emerging demand with stringent specification from these industries has marked jet mill as one of the essential grinding mill to produce ultra fine talc. Ultra fine grinding testwork of talc was carried out in opposed fluidized bed jet mill by varying the feed rate, classifier rotational speed and grinding pressure at three levels. In this jet mill, grinding and classification took place simultaneously. The ground products were characterized in terms of particle size distribution and mechanochemical effect via X-ray diffraction. The ground product exhibited poly-modal distribution and the minimum size obtained was 4.28 µm at 4 kg/h, 13000 rpm and 4 bar. Besides size reduction in micron range, mechanochemical effect was exhibited by the product ground in jet mill as jet mill is classified as high-energy mill. Reduction in peak intensity and peak base broadening was observed which indicates fine grinding process in jet mill induced mechanochemical effect. Furthermore preferential distortion of (00l) planes was observed as well. The degree of crystallinity of ground sample, which ranged from 26.5% to 85.3% reduces as the specific kinetic energy increase and its reduction gradient varies according to the classifier rotational speed. The crystallite size and lattice strain of talc ranged from 147.69 nm to 353.72 nm and 0.08 to 0.2 respectively

Study Of The Clinker Characteristics And Grindability During Cement Production.

The quality of cement product is dependent on a number of factors such as the quality of the raw material, the chemical changes during burning and cooling stages and the fineness of the grinding. Mineralogical and chemical studies on clinker will provide information about clinker characteristics and about conditions occurring at various stages of the manufacturing process

Sustainable Mineral Development through Value Adding Of Local Industrial Minerals for Manufacturing Industries

Malaysia is endowed with plenty of industrial minerals such as silica, limestone, mica and kaolin. Besides that, the vibrant growth of manufacturing industries needs these minerals as their raw materials in their manufacturing processes and these industries are setting stringent specification for the raw materials used in their processes. Availability of local mineral resources and vibrant growth of the manufacturing industries has creates a vital needs to develop and value add the local mineral resources through development of advance mineral processing techniques in order to create win-win situation between the mineral industry and manufacturing industries. This study will focus on value adding of the local industrial minerals through fine grinding process to produce high performance mineral fillers for plastic industry. This technology is considered green as it consume less energy and produce minimal pollutants compare to the current processes. Besides cost reduction, the performance of the plastic products has been enhanced in terms of mechanical and thermal properties by incorporating these high quality mineral fillers which makes these high quality products affordable for the bottom billions. Sustainable development of these mineral resources is essential as these mineral resources are nonrenewable.</p

Extending the application of JKFBC for gravity induced stirred mills feed ore characterisation

Although stirred mills have been used widely in the mineral processing concentrators for fine grinding purposes, till date a standard ore characterisation test is not available for this technology. Advanced process modelling requires ore hardness index and ore specific breakage functions for accurate predictive capability. The Julius Kruttschnitt Mineral Research Centre (JKMRC) has pioneered the initiative to develop a practical ore characterisation test for the fine particles (within stirred mill regime). The JKFBC (JK fine-particle breakage characteriser) was used to develop an index that represents the ore hardness of the stirred mill feed. The index is called Stirred mill index (SM). This index measures the particles hardness and generate a generic tn-family curve (to establish energy base breakage function). Four types of materials were chosen for the test work i.e. Au-Cu ore, limestone, Fe ore and Au ore. The JKFBC test works were carried out by varying the applied vertical load, mill rotational speed and number of revolutions to achieve various levels of energies. The energy regimes chosen in this test work were within the typical operational conditions of the industrial scale gravity induced stirred mills. The test was modified from the original Shi's test methodology by reducing the thickness of the particles bed in the mill and specific energy consumption. The volume of the material in the mill is kept constant to avoid the particle density effect. A new t function that incorporates the size effect was used to describe the breakage in the JKFBC. Ore hardness of the fine particles (between 1180 and 53 μm) was quantified through SM. A preliminary tn-t family curves was developed that responds based on the hardness of the samples - SM and energy. Further work in extending this procedure with other types of ores are essential for a more robust model parameters. This preliminary development has enabled a more predictive stirred mill process model development that incorporates the ore characteristics in the selection function

Assessment of hydrocyclone operation in gravity induced stirred mill circuit

The performance data of hydrocyclones in circuits containing a gravity induced mill (hereafter referred to as a stirred mill) were evaluated to understand their performance in the circuits and the current operational practices. There are many studies conducted to understand and evaluate the hydrocyclone performances in the semi-autogenous mill (SAG) and ball mill circuits. The literature on hydrocyclone operation in stirred milling circuits is still limited. A database consisting of various hydrocyclone sizes, operating conditions, classification duties, and commodities was developed based on extensive circuit surveys. The database was used to evaluate the hydrocyclone performance. Among the key operational issues observed were poor circuit control strategies, improper hydrocyclone sizing and operation in the roping condition. Analysis of long-term operational data indicated that hydrocyclone feed solid density is an essential operating variable that needs to be controlled to maintain the cut size. An increase in hydrocyclone feed density leads to an increase in cut size. Almost 50% of the hydrocyclones (in the database) were operating in the roping condition. Besides the hydrocyclone feed solid density, high amounts of fine particles (−25 μm) in the hydrocyclone feed also caused the roping condition. Further research is required to operate the hydrocyclone in a spraying condition when the feed has high solid-density and a high content of fines. Plitt’s cut size model was fitted to the data set to evaluate its capability to be used in the stirred mill’s hydrocyclone. The analysis shows the Plitt’s model can predict the cut size when the hydrocyclone is in spraying mode. This result indicates that Plitt’s model can be used for the regrind duty hydrocyclones. An empirical model was developed relating the hydrocyclone feed density and the Plitt onset roping hydrocyclone underflow density. This model can be used to predict the roping condition. Finally, the impact of hydrocyclone performance on circuit performance was compared through the size specific energy of the mill. High size specific energy values were observed when the hydrocyclone is operating in the roping condition. These findings are based on the real operating condition, and it shows the importance of operating the hydrocyclone optimally to achieve overall circuit efficiency