briefly explain how alumina is produced from bauxite?
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bauxite is first turned into pure alumina(AL203) by baeyer's process.then aluminium is obtained from alumina by electrolysis. but melting point(2348k) of alumina is very high . so it is mixed with molten cryolite and florspar . this mixture i sput into a tank containing graphite lining(cathode). carbon rods(anode) are dipped into the mixture.molten aluminium is collected at the cathode.oxygen is evolved at the anode. this oxygen combines with the crbon in the carbon rod and forms carbon di oxide. hence the crbon rods need to be replaced frequently.
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Cement is composed of five types of minerals such as  limestone, shale, silica, pyrite and gypsum.  Limestone were grounded from the impact crusher (mostly 1 cubic meter size) to as big as half the coconut shell, then it is will again passed through a jaw crusher from this size, it will be like 3/4". After this the lime stone will pass through the ball mill(a rotating drum consist of different sizes of ball metals) with other ingredients.  The product will be like a face powder.  \n(For Semi-dry process)\nThis face powder like shall go through a tilted rotating pan, where a tricle of water will make a sphere size as size as a marble. This sphere size mixture shall pass through the calcining stage(this is removing the moisture in it).  After the calcining stage, it will pass through a rotating kiln  at a temperature of about 2,700 degrees celcius.  This temperature is enough to burn and turn red your mixture(similar to volcanic lava).  The product of these is like charcoal and what you call clinker.  It will pass through the last process to make it cement.  Another ball mill(mostly this is called the finished mill) and with the same texture(face powder like) and mixed this with gypsum then you got portland cement.\nNow are you ready to turn the soil into like a volcanic lava?
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OK, here goes---no chemical formulas--look that up in your chemistry book.\n\nLead is mined.  The ore comes out of the mine as a Lead Oxide.  Chunks of ore range from about the size of a loaf of bread on down.  Ore goes through jaw crushers to reduce in size.  Golfball size ore goes through a rod mill. (Large revolving drum full of steel rods)  Comes out pea sized.  Ore goes into a ball mill. (Large revolving drum full of steel balls)  Comes out the size and consistency of talcum powder)   The ore/water mixture is called a slurry.  The slurry comes out of the ball mill and goes into flotation chambers where a mixture of water and foaming agents are being agitated.  The lead particles in the slurry attach themselves to the bubbles created by the foaming agent.  They rise to the top of the tank where the foam is scraped off by paddles.  Waste rock called tailings is pumped in a slurry form to a disposal site.  The lead bubble foam is transported to a dryer.  The dryer removes excess water and leaves the final product of the mine and mill--lead concentrate.  (lead oxide)\n\nThe concentrate is hauled to the smelter.  If it was put into the furnace in its current state it would go right up the chimney---the lead is the consistency of talcum powder.  In order to melt the lead, we have to hold it in place long enough to melt so that it doesn't all just blow out the chimney.  This is done by a process called sintering.  Lead concentrate is added to crushed limestone, coke and other chemical reagents.  It is then run through the sintering machine.  The sintering machine roasts the mixture for 20 minutes and when the sinter comes out the end of the machine it resembles the klinkers that you'll see come out of an old coal fired furnace.  The roasting process causes all the ingredients to mold together into a solid chunk---called sinter.  The sinter comes out of the machine in huge chunks---as big as a car---and is run through a crusher to break it up into manageable size--about the size of a basketball on down.  The sinter goes into a storage bin.\n\nNow, its time for the furnace.  The sinter is mixed with more powdered limestone, iron ore, coke, coke breeze, lead scraps from spills.  This mixture is fed into a top feed furnace.  As the mixture falls down into the bottom of the furnace it encounters the fire.  Pure oxygen is pumped into the furnace, feeding the fire.  The coke and coke breeze burn creating enormous amounts of heat.  The sinter holds the lead in place long enough for it to melt and flow into the bottom of the furnace.  The sinter is then consumed by the fire as its remaining ingredients are partially cooked coke.  When the bottom of the furnace fills up with molten lead, it is tapped by the furnaceman.  The furnaceman will drain off a huge kettle full of molten lead.  Once the kettle is full the furnaceman will shut off the flow.  An overhead crane picks up the kettle and takes it over to the refinery area.\n\nA lot of sulfur containing compounds are generated as by-products of the smelting process.  At one plant I worked at they had an acid plant on site.  By scrubbing the furnace's exhaust gasses, they removed most of the SO2 from the exhaust.  The SO2 was then sent to the acid plant where a chemical reaction took place and the SO2 was changed to sulfuric acid---H2SO4.  The acid plant would produce a rail car full of 98% pure sufuric acid every day.\n\nThe scrubbed exhaust gasses went into another scrubbing device called the 'baghouse'.  This was a huge four story building about the size of a city block.  Every floor had dozens of rooms on it.  Each room was filled with bags that stretched from the ceiling of the room to the floor.  This bags were made of cloth---they were filter bags.  The exhaust gasses passed through these bags and the most minute particles were filtered out. The remaining exhaust gasses went up the chimney.\n\nWhoa--that brought back memories!  Believe me, you haven't lived t
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The ground. Bauxite is mined and the aluminum separated from it using a electro-chemical process.
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The solid product is calcium carbonate, which is chalk :)\n\nHere's the balanced reaction if you're interested:\nCaCl2 (aq) + Na2CO3 (aq) ----> 2 NaCl(aq) + CaCO 3(s)
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Probably some of the aluminum caught fire in the fireball from the burning hydrogen.  If so, the reaction would be:\n\n4 Al +  3 O2 =====> 2 Al2O3
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Al2(SO4)3 ==> Al2O3 + 3SO3
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2 HNO3(aq) + Sr(OH)2(aq) --> Sr(NO3)2 (aq) + 2 H2O\n\n2 H3PO4(aq) + 3 Ba(OH)2(aq) --> Ba3(PO4)2 (cr)* + 6 H2O\n\n* Barium Phosphate will precipiate out of an aqueous solution in this reaction
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Aluminum DOES rust; it just isn't like iron rust. Aluminum oxide (chemical formula Al2O3) forms a thin film on the outside of the aluminum. \n\nSome people say, figuratively, that we have never really seen aluminum, because the oxide coating forms so quickly; (I have to disagree with what someone else wrote above) you can't scratch aluminum and then see the true color before the oxide covers it.\n\nAl2O3 is chemically the same as sapphire, it is very hard and strong. Once the coating has formed on the surface, it protects the rest of the aluminum in the bulk of the piece, so it doesnt corrode away. The coating is very thin, though-- only one molecule thick-- so we don't notice it and it doesn't really add any structural strength to the aluminum. \n\nBy contrast, iron rust is very weak. It crumbles and falls apart very easily; it can't even support its own weight. So it breaks off the surface of the iron and leaves fresh iron exposed to rust. That is why bridges and girders fall alart if they are not painted or protected from the elements. But aluminum protects itself.
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Melt the whole mixture and do an electrolysis. Would be quite expensive a process, but might be the only possibility e. g. on the moon in order to produce oxigen. Melting heat might come from sun and electricity from solar panels.\n\nI understood in principle such a reaction is done to make aluminium from bauxite. But in this case the producers immediately use up the oxigen through burning carbon electrodes in order to win the melting heat.
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The aluminum starts out in a flat ribbon form.  From this ribbon, a circular disk is punched out.  This disk is drawn out into a cylindrical can through several processes. Once the can is drawn, then the top is trimmed for a smooth, level edge.\n\nThe cans are then cleaned, washed and dried before they are filled with product (such as soda/pop).  Almost immediately after the can is filled, a lid top (with the mechanism that you use to open the can) is put on and then crimped to the lower section of the can by a machine called a seamer.
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the ores of aluminium are\n1>bauxite\n2>gibsite\n3> cryolite\n4>diaspore \nand so on......................................
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understanding the reaction meachanism \neffect of catalysts etc....\ndetermining the amounts needed
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The Manufacturing\nProcess\nQuarrying limestone\n\n    * 1 Approximately 95 percent of the limestone produced in the United States is quarried. After a sufficient reserve (twenty-five years' worth is recommended) has been prospected, the land that covers the deposit is removed with bulldozers and scrapers. If the chalk is close to the surface, an open shelf quarry method can be used; however, this is very rare. Usually an open pit quarry method is used instead. In this method, holes are drilled into the rock, explosives are placed inside, and the rock is blown apart. Depending on the nature of the deposit, a pit can be enlarged laterally or vertically.\n\nPulverizing the chalk\n\n    * 2 Once comparatively large chunks of limestone have been quarried, they need to be transported to crushing machines, where they are pulverized to meet the demands of the chalk industry. The first step is primary crushing. Various crushers exist, but the principle is the same: all compress the stone with jaws or a cone, or shatter it through impact. Secondary crushing is accomplished by smaller crushers that work at higher speeds, producing pebbles which are then ground and pulverized.\n    * 3 The next phase, wet grinding, washes away impurities. It is used to make the fine grade of limestone necessary to make chalk suitable for writing purposes. Wet grinding is carried out in ball mills—rotating steel drums with steel balls inside that pulverize the chalk until it is very fine.\n\nAfter grinding, the chalk particles are sifted over vibrating screens to separate the finer particles. The particles are then mixed with water, extruded through a die of the proper size, and cut to the proper length. Finally, the chalk is cured in an oven for four days.\nAfter grinding, the chalk particles are sifted over vibrating screens to separate the finer particles. The particles are then mixed with water, extruded through a die of the proper size, and cut to the proper length. Finally, the chalk is cured in an oven for four days.\n\nDehydrating gypsum\n\n    * 4 Gypsum, like limestone, is also quarried and pulverized. The major difference in processing gypsum is that it must be dehydrated to form calcium sulfate, the major component of colored chalk. This is done in a kettle, a large combustion chamber in which the gypsum is heated to between 244 and 253 degrees Fahrenheit (116-121 degrees Celsius). It is allowed to boil until it has been reduced by twelve to fifteen percent, at which point its water content will have been reduced from 20.9 percent to between 5 and 6 percent. To further reduce the water, the gypsum is reheated to about 402 degrees Fahrenheit (204 degrees Celsius), at which point it is removed from the kettle. By now, almost all of the water has evaporated, leaving calcium sulfate.\n\nSifting, cleaning, and shipping\nthe chalk\n\n    * 5 The particles of chalk or calcium sulfate are now conveyed to vibrating screens that sift out the finer material. The ensuing fine chalk is then washed, dried, packed in bags, and shipped to the manufacturer. Upon receiving chalk or calcium sulfate, the chalk factory usually grinds the materials again to render them smooth and uniformly fine.\n\nMaking white classroom chalk\n\n    * 6 To make white classroom chalk, the manufacturer adds water to form a thick slurry with the consistency of clay. The slurry is then placed into and extruded from a die—an orifice of the desired long, thin shape. Cut into lengths of approximately 24.43 inches (62 centimeters), the sticks are next placed on a sheet that contains places for five such sticks. The sheet is then placed in an oven, where the chalk cures for four days at 188 degrees Fahrenheit (85 degrees Celsius). After it has cured, the sticks are cut into 80 millimeters lengths.\n\nMaking colored classroom chalk\n\n    * 7 Pigments (dry, natural, colored materials) are mixed in with the calcium carbonate while both are dry (the procedure is similar to sifting flo
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Here's how u can do it:\n\n(Step 1): Take an asbestos sheet of any diameter you like depending upon the size u want to make.\n\n(Step 2): Take a long jar and build a mountain with modelling clay with a hollow(but not very deep) pit.\n\n(Step 3): Leave it in the sun for drying.\n\n(Step 4): Get Ammonium Dichromate (NH4)2Cr2O7 from a chemical shop.\n\n(Step 5): Place a small amount of Ammonium Dichromate into the pit and drop a lighted camphor in the pit. You will see that Ammonium Dichromate increases in its volume, sparks are evolved and a green coloured lava flows out of the pit.\nThis is Chromium Oxide and the reaction can be represented like this:\n(NH4)2Cr2O7 --> Cr2O3 + 4 H2O + N2\n\nNote: Ammonium Dichromate and camphor are both toxic chemicals. Have a teacher around you to help u and keep a bucket of water near u.
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Making of Fertilizers:\nBasically, fertilizers are made from ammonia..I will take you through four stages that are basically followed in order to make ammonia..mind it that I am talking about artificial fertilizers not natural ones like cow dung which is not man-made...Alright then,\n\nSTAGE 1: Haber Process\n\nThis is a reversible reaction and an exothermic reaction thats used to make Nitrogen and Hydrogen under low temperatures (about 750 degrees celcius) and high pressures (about 30 atmospheres with a catalyst of nickel)..The reaction for this equation is:\n\nN2 + 3H2 <---> 2NH3  (-92kJmol -1)\nNitrogen + Hydrogen <---> Ammonia\n\nNow we have got our ammoina..which is the raw material in the production of fertilizers..Lets move on to the 2nd step...\n\nSTAGE 2: Ammonia being converted into Nitrogen Monoxide..\n\nIn this stage, we are going to let ammonia (which we got from the Haber process) react with oxygen to form nitrogen monoxide and water..\nFor this reaction to take place..we need to apply heat and catalyst (not so sure of which catalyst). We need to apply 230 degrees celcius of heat for heating air and ammonia). So, here's the reaction equation for that:\n\n4NH3(g)  +  5O2(g)  --->  4NO(g)  +  6H20(l)\n\nWe've got our Nitrogen monoxide now..so let's move on..\n\n\nSTAGE 3: Converting Nitrogen Monoxide into Nitric Acid\n\nIn this reaction we are going to react Nitrogen Monoxide with Oxygen and Steam to obtain Nitric Acid like this:\n\n4NO(g) + 3O2(g) + 2H2O(g) ---> 4NO3(aq)\n\nSTAGE 4: Converting this Nitric Acid into Ammonium Nitrate\n\nSo, Now nitric acid is going to be reacted with Ammonia (from Haber Process again..) in an addition reaction. Ammonium Nitrate in this case, will be our fertilizer..So, this is the final stage.. <Phweks!!> Here we go:\n\nNH2(g)  +  HNO3(aq)  --->  NH4NO3(aq)\nAmmonia gas + Nitric Acid ---> Ammonium Nitrate!!!\n\n\nUses:\nThe ions these fertilizers contain enrichen the soil very much..Ions like the nitrates and phosphates are absorbed by the plants through osmosis from the soil..These ions then help the plant in various stuff like synthesising the chlorophyll molecule..some like nitrates are converted into plant proteins...\n\nOk, I guess I have exhausted everything I know about fertilizers...\n\nI really hope it was of some help for u...   :)
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The presence of titanium oxide in corundum turns it into blue sapphire. The presence of chromium turns it into red ruby. \n\nPure corundum is a translucent brown rock.