Pyrophyllite: An Economic Mineral for Different Industrial Applications

Pyrophyllite (Al2Si4O10(OH)2) is a phyllosilicate often associated with quartz, mica, kaolinite, epidote, and rutile minerals. In its pure state, pyrophyllite exhibits unique properties such as low thermal and electrical conductivity, high refractive behavior, low expansion coefficient, chemical inertness, and high resistance to corrosion by molten metals and gases. These properties make it desirable in different industries such as refractory; ceramic, fiberglass, and cosmetic industries; as filler in the paper, plastic, paint, and pesticide industries; as soil conditioner in the fertilizer industry; and as a dusting agent in the rubber and roofing industries. Pyrophyllite can also serve as an economical alternative in many industrial applications to different minerals as kaolinite, talc, and feldspar. To increase its market value, pyrophyllite must have high alumina (Al2O3) content, remain free of any impurities, and possess as much whiteness as possible. This paper presented a review of pyrophyllite’s industrial applications, its important exploitable properties, and the specifications required for its use in industry. It also presents the most effective and economical techniques for enriching low-grade pyrophyllite ores to make them suitable for various industrial applications.

Oxygen Sensors for Industrial Application

The present work aimed to study a family of solid ceramic electrolytes based on magnesium oxide doped zirconium oxide, usually identified as Mg-PSZ (zirconia partially stabilized with magnesia), used in the manufacture of oxygen sensors for molten metals. A set of electrolytes was prepared by mechanical (milling) and thermal (sintering) processing, varying the composition in magnesia and the cooling rate from the sintering temperature. These two parameters are essential in terms of phase composition and microstructure of Mg-PSZ, determining the behavior of these materials. The structural and microstructural characterization was done by means of X-ray diffraction (XRD). The electrical properties were analyzed by impedance spectroscopy in air. In general, the results obtained from various concentrations of dopant, different cooling rates and the same sintering step condition showed an increased conductivity for samples with predominance of high temperature stable phases (tetragonal and cubic).

Mixing, Mass Transfer, and Numerical Models

We want to eliminate dissolved impurities to another phase: slag, gas, solid, or a molten metal that has limited solubility in the main metal. The various phases may be in the form of droplets, bubbles, particles, or walls. The contact areas with metal should be large. The aim in reactor design and operation is to achieve relatively high velocities and small dimensions. Relations for mass transfer are also included since the behaviour of systems with molten metals may be different from that usually treated in chemical engineering. In the field of turbulence the Prandtl eddy length is important for describing removal to walls. Hydrogen in aluminium and the pick-up of hydrogen in aluminium from water vapour is studied in some detail, measured, and modelled. It is taken into account that hydrogen gas is two-atomic. The approach concerning aluminium may be applied to a range of metals.

Removal of Dissolved Impurities from Molten Metals

Impurities are transferred out at the boundary of the liquid. Velocities normal to the boundary are small. Therefore, for efficient removal contact areas and times should be large. Transfer depends on the chemical and physical properties of the liquid and the phase that captures the impurities at the boundary. This phase may be a liquid, gas (vacuum) or solid. Properties can be described in terms of equilibrium and empirical mass transfer coefficients. Vacuum may be applied to remove volatile elements. Refining can be carried out by partial solidification or fractional crystallisation, using the segregation that occurs during freezing of an alloy. Finally, an element can be added to form a reactive compound followed by removal of the compound by sedimentation or filtration.

Thermodynamics and Transport Properties

The fundamentals of thermodynamics are reviewed, focusing on the chemistry of high-temperature metals, oxides (slags), and salts. Thermochemical data are provided for important molten metals: the free energies of solution of alloy elements, and interaction coefficients. Standard free energies of reactions are also provided, so the reader may calculate important chemical equilibria. Example calculations are provided for the deoxidation of steel. The removal of sulfur and phosphorus are also described. The second half of the chapter considers fundamental aspects of important physical properties: viscosity, surface tension, diffusion, and thermal and electrical conductivity.

Removal of Inclusions from Melts

Inclusion origins and the methods for determining the content of inclusions in a melt are described. Removal of inclusions by flotation/settling is demonstrated. The method for removing inclusions from molten metals by bubbling is described in detail with attachment mechanism to bubbles. Use of microbubbles are included. Filtration capture mechanisms of inclusions, cake and deep bed mode, are derived. A model for removal of inclusions by ceramic foam filters is introduced. Re-entrainment of inclusions are examined. In addition the use of rotational and electromagnetic forces to remove inclusions is explained. The number size distribution of inclusions is taken into account, both the change in the distribution function and the growth of inclusions with time. In the end the interaction of dissolved elements and inclusions is described.

Determination of Corrosion Resistance Properties of Al-Sio2 Composite Material

The Al-Sio2 Composite work are widely used in engineering application in automotive industry in india and other countries. The Al-Sio2 composite has been mainly used on high corrosion resistance material. The material used as a high thermal application also. Example boiler shield and engine shield also. The main performance of Al-Sio2 material used in a corrosion resistance properties. Because the aluminum composite material when goes to the heat treatment application. The material was meeting in corrosion. In this way engineering industry was affected. So we are currently focused the work corrosion resistance application. In this work we have used for the Al-Sio2 material was reinforced in aluminum 6061 material. The material was developed by stir casting method. The method the stirrer was run by 2000 RPM. And the material was molten by 550 degree temperature. That time the Al-Sio2 powder was dropped by the molten metals. Hence the composite now formed by Al-Sio2 composite material. After that we have checked by the SEM fractures and XRD measurement and other material properties also and also fracture surface of the materials. Finally we have concluded the result of work also.

IMPROVEMENT OF RESCUE OPERATION WHEN POSTING GRINDING BALLS INTO A DIGGER

A characteristic feature of modern industries is the steady growth of mechanization and automation of production processes. The economic and social significance of mechanization is manifested in a wide range of measures aimed at replacing manual labor with machines and mechanisms, the transition to higher levels of mechanization, and ultimately to the highest degree of mechanization of automation. The combined development of science and technology significantly affects both complex and partial (non-complex) mechanization of production processes, generating an increase in the number of parts. A significant place in the technology of manufacturing parts is the casting process. About half of the parts are made of molten metals and other materials. One of the common methods is die casting. Shells (molds) of metal or cast iron molds, for free (gravitational) filling with liquid metal, are used repeatedly. Detachable and non-removable (solid) molds are used. The opening surface of the detachable mold can be horizontal, vertical, or combined. The subject of the study is a mold, which consists of two half-shapes with a vertical opening surface and pins of mutual centering of the shells. A wide range of enterprises: mining and processing plants, cement plants, construction plants, energy generating companies, etc. use the products of casting in the mold grinding layers. All types and sizes of grinding layers are intended for grinding of raw materials. Due to various technical reasons, during casting, a metal film is formed near the grinding balls, which fills the entire surface of the opening of the detachable mold. The operation of removing the lattice from the grinding layers is necessary to reproduce the geometric shape, quality requirements and considerations of industrial aesthetics of the product. Performing such an additional operation requires the collective work of employees with the use of physical force and appropriate tools. Existing technology with the use of metalwork tools leads to a deterioration in the appearance of the layers, and sometimes to damage the products. The essence of improving the lattice operation is to use a specially designed device for this operation, which in turn creates the conditions for mechanization of the production of grinding balls.

Methane Cracking for Hydrogen Production: A Review of Catalytic and Molten Media Pyrolysis

Currently, hydrogen is mainly generated by steam methane reforming, with significant CO2 emissions, thus exacerbating the greenhouse effect. This environmental concern promotes methane cracking, which represents one of the most promising alternatives for hydrogen production with theoretical zero CO/CO2 emissions. Methane cracking has been intensively investigated using metallic and carbonaceous catalysts. Recently, research has focused on methane pyrolysis in molten metals/salts to prevent both reactor coking and rapid catalyst deactivation frequently encountered in conventional pyrolysis. Another expected advantage is the heat transfer improvement due to the high heat capacity of molten media. Apart from the reaction itself that produces hydrogen and solid carbon, the energy source used in this endothermic process can also contribute to reducing environmental impacts. While most researchers used nonrenewable sources based on fossil fuel combustion or electrical heating, concentrated solar energy has not been thoroughly investigated, to date, for pyrolysis in molten media. However, it could be a promising innovative pathway to further improve hydrogen production sustainability from methane cracking. After recalling the basics of conventional catalytic methane cracking and the developed solar cracking reactors, this review delves into the most significant results of the state-of-the-art methane pyrolysis in melts (molten metals and salts) to show the advantages and the perspectives of this new path, as well as the carbon products’ characteristics and the main factors governing methane conversion.