MIP LESSON 1

• Unit operation is a basic step in a process that involves physical change or chemical transformation during the process.
• Manufacturing may be defined as the sequential application of technical unit operations to increase or convert raw material, or materials, to a high-value added component or device.
• Types of unit operations include Mechanical Operations, Fluid-flow operations, Heat-transfer operations, and Mass-transfer operations.
• Mechanical operations include Transportation, Screening, Size Reduction, Filtration, Clarification, Mixing.
• Mechanical operations equipment includes Sieves, Fluidization apparatus, Plate filter press, High temperature high pressure filter press, Solids handling study bench, Sigma mixer, Roll crusher, Basket centrifuge, Froth flotation unit, Ball mill, Belt conveyor, Bucket conveyor.
• Material balance states that matter can neither be created nor destroyed.
• Energy balance is used to determine the amount of energy required to carry out an operation.
• Ideal contact is important to know how much the material being processed is in contact for any length of time under specified conditions, such as conditions of temperature, pressure, etc.
• Rates of an operation refer to the equilibrium that must be attained for further change can take place and the process stops, however the process tends to keep going.
• Solid-to-solid separation properties of solids include Density and Bulk Density.
• Density is expressed by the symbol ρ and is defined as the mass per unit volume.
• Bulk density, also known as "Apparent Density", is the total mass per unit total volume.
• Trommel screens are frames made of cylindrical, conical, or prismatic frames surrounded by woven wires or punch plate screens that acts as the screening surface, usually open at both ends at a slight angle to initiate material flow.
• Lower slope angles in a bana na screen result in reduced material flow rates but higher efficiency screening of near-sized materials.
• Oversize particles are discharged through centrifugal force generated by the gyratory vibration into the outer end of the screen.
• Compound trommels are concentric trommels with the same shaft, different screen aperture size.
• Vibrating screens have high capacity and efficiency.
• Gyratory screens consist of a series of decks with its own discharge spout (up to four decks).
• Undersize particles are discharged through gravity at the bottom of the screen.
• Bana na screens are a recent innovation in the 21st century with the key feature of changing slope sections (declinations) to increase material flow.
• Steeper slope sections in a bana na screen result in high material flow rates and rapid fines removal.
• Stages in a bana na screen include: feed inlet, screening area, and discharge outlet.
• The meanings of vibration in vibrating screens are: CAM-operated vibrating screens use centrifugal vibration, eccentric shaft vibration, or both.
• Trommel screens can be arranged in a single trommel with different screen opening sizes, in series where the first one has the largest screen aperture size so that the undersize products become the feed of the next trommel, and so on, or in series where the first one has the smallest screen aperture size so that the oversize materials become the feed for the next trommel, and so on.
• Applications of screening include mining and mineral processing, food industry, chemical industry, plastics and recycling, pharmaceuticals.
• Vibrating screens are widely used screen equipment and are the standard equipment for screening coarse, medium, and fine materials.
• Feret’s diameter is the mean distance between two parallel tangents to the projected particle diameter.
• Screen aperture is the clear size between the individual wires of the screen.
• Screening or sieving is a mechanical operation used in separating large particles into specific size fractions.
• Purposes of screening include removing the coarse particles for further size reduction, removing the fine particles from crusher feeds to save power by preventing over-grinding, grading the crushed products into commercial sizes, and performing a step for subsequent processes.
• Mechanical separation techniques include centrifugal separations, chromatography, electrostatic separation, elutriation, filtration, floatation, flocculation, fractional freezing, jigging, magnetic separation, precipitation, scrubbing, sedimentation, sieving, sorting, tabling.
• Soil in reality, contains moisture (20% water).
• Brittleness/Frailty is a property of a material to be easily broken by impact, for example: the brittleness of coal is ideal when gravity crushing coal for stokers.
• Terminologies used in screening include particle, dimension of a particle, Martin’s diameter, Feret’s diameter, screen aperture, mesh, screen interval.
• Porosity is the amount of available spaces known as void spaces of a raw material in which water or air (or other materials) can fill up with.
• Depending on soil compaction, contains air on void spaces.
• In some cases, the bulk density of a specific material is not equal to the actual density of the raw material.
• Nonporous materials have a density equal to its true density, for example: diamond, block of pure aluminium.
• Mesh is the number of screen apertures per unit length, with the larger the mesh number, the finer the screen.
• Hardness is the resistance of materials to indentation and scratching.