Lime Making

Lime manufacturing is one of the oldest processes known to man, having been carried out since prehistoric times. The remains of fossils, according to geologists, formed the limestone bed thousands of 

Lime was and still is used in soil stabilization, road building, chemical manufacture, the tanning process, and the purification of water, whitewashing buildings, treating animal hides and leather, and for plaster and mortar. The US National Lime Association tends to think that lime is the versatile chemical.  

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Treatment of Industrial Wastes. The alkaline nature and inexpensive price of lime make it ideal for treatment of acid waste Hquors (6), including waste pickle Hquids from steel plants, wastes from metal plating operations, eg, chrome and copper plating, acid wastes from chemical and explosives plants, and acid mine wastewaters. 

For while all bodies are composed of the four elements, that is, of heat, moisture, earth and air, yet there are mixtures according to natural temperament which make up the natures of all the different animals of the world, each after its kind. Therefore, if one of these elements, heat, becomes predominant in any body whatsoever, it destroys and dissolves all the others with its violence.. . Again, The reason why lime makes a solid structure on being combined with water and sand seems to be this that rocks like all other substances are composed of the four elements. Those which contain a larger proportion of air are soft, of water, are tough from the moisture, of earth, hard, of fire more brittle. Therefore, if limestone without being burned is merely pounded up small and then mixed with... 

The sedimentation, or settling, of suspended matter takes place in large tanks and is accelerated by the addition of lime, CaO, and aluminum sulfate, A12(S04)3. The lime makes the water slightly basic, which precipitates the added Al3+ ions as aluminum hydroxide ... 

The use of sulfur dioxide in addition to lime makes a better clarification. In this method (sulfitation process), lime is added as usual, but then sulfur dioxide from a sulfur burner is bubbled through the juice. The precipitate is settled as in the ordinary clarification process. The bleaching effect of sulfur makes a lighter-colored sugar. The extra cost of sulfitation, increased sealing in heaters and evaporators, and higher ash in raw sugars are reasons for the discontinuance of this process. 

In Southeast Asia, the betel nut, which in fact is the seed of the betel palm (Areca catechu), is commonly used for its mildly narcotic effect. The betel nut is chewed with a leaf of a local pepper plant and this in combination with a bit of lime makes the mouth and saliva red. With constant use, the teeth of betel addicts turn black. It has been estimated that a tenth of the world population chews betel nuts. 

Strychnine is prepared from the seeds by grinding them to a paste with slaked lime and water. The paste is dried and mixed with a suitable organic solvent (formerly benzene was used, but now less harmful solvents are substituted, e.g. chloroform). The slaked lime makes the mixture alkaline and under these conditions the strychnine dissolves readily in organic (i.e. oily) but not water-based solvents. The particulate debris is then removed by filtration and the liquid shaken with dilute sulphuric acid. This neutralises the effects of the lime and when the organic solvent and acid layers separate (cf. oil and vinegar salad dressing) the strychnine is dissolved in the latter. The organic solvent is decanted from the strychnine solution which is rendered alkaline by the addition of either ammonia or sodium hydroxide. This drastically reduces the... 

Some of the processes discussed include lime making, cement making, carbothermic reduction kilns, and lightweight aggregate kilns. 

Coagulation based on aluminum or iron salts, with possible lime make up (coprecipitant) so as to densify the floe, and an anionic polyelectrolyte make up (flocculating agent). 

There is interest in lime sludge classification in both wastewater and potable water treatment plants. If the magnesium hydroxide content of a lime sludge can be suitably reduced, the residual calcium carbonate can be recalcined to calcium oxide. Too much magnesium hydroxide will prevent the slaking of the lime. The restrictions and rising cost of disposal of spent lime makes recovery and recycling attractive. 

A great many measurements were made of the changes of bulk in the operations of slaking lime, making mortars, c., and the results, as might be expected, varied with the qualities of the lime. The following condensation of the results may be useful. 

An additional useful test is to distil the acid or its sodium salt with soda lime. Heat 0.5 g. of the acid or its sodium salt with 0 2 g. of soda lime in an ignition tube to make certain that there is no explosion. Then grind together 0-5 g. of the acid with 3 g. of soda hme, place the mixture in a Pyrex test-tube and cover it with an equal bulk of soda hme. Fit a wide dehvery tube dipping into an empty test-tube. Clamp the tube near the mouth. Heat the soda lime first and then the mixture gradually to a dull-red heat. Examine the product this may consist of aromatic hydrocarbons or derivatives, e.g., phenol from sahcyUc acid, anisole from anisic acid, toluene from toluic acid, etc. 

Platinum is a beautiful silvery-white metal, when pure, and is malleable and ductile. It has a coefficient of expansion almost equal to that of soda-lime-silica glass, and is therefore used to make sealed electrodes in glass systems. The metal does not oxidize in air at any temperature, but is corroded by halogens, cyanides, sulfur, and caustic alkalis. 

Lemon and Lime Juice. Lemons and Persian limes can be extracted using the same PMC and AMC extractors described above. The juice can be concentrated in a TASTE evaporator, an APV Crepaco, Inc. evaporator, or other types of evaporators (13). Although lime juice, and especially lemon juice, are widely used as condiments on food, the bulk of concentrated juice is used to make frozen concentrated lemonade and limeade. Prozen... 

Splitting. In most modem large tanneries that make upholstery leather, and in some that make shoe uppers leather, the hides are spHt in the lime condition. In splitting the hides are cut to the desired thickness with a horizontal belt knife. The hides are fed into the machine grain up. The clearance between the grain and the blade is maintained by a series of narrow rollers supported by a mbber roUer underneath the spacing roUers. The grain layer is then cut to the thickness desired to an accuracy of about 0.1 mm. 

Puilding lime may be quick or hydrated lime, but usually coimotes the latter, where the physical characteristics make it suitable for ordinary or special stmctural purposes (see Building materials, survey). 

Finishing lime is a refined hydrated lime, milled to make it suitable for plastering, particularly the finish coat. Putty derived from this hydrate possesses unusually high plasticity. 

The manufacture of hydrated lime proceeds by the slow addition of water to cmshed or ground quicklime in a premixing chamber or a vessel known as a hydrator, both of which mix and agitate the lime and water. The amount of water added is critical. Too much water makes it impossible, or too cosdy, to produce the desired dry form too Httle water leaves hydration incomplete, causing degraded quaUty, namely, chemical instabiUty and stmctural unsoundness. 

Petroleum. Apart from its use ia petrochemicals manufacture, there are a number of small, scattered uses of lime ia petroleum (qv) production. These are ia making red lime (drilling) muds, calcium-based lubricating grease, neutralization of organic sulfur compounds and waste acid effluents, water treatment ia water flooding (secondary oil recovery), and use of lime and pozzolans for cementing very deep oil wells. 

Naphthalenesulfonic Acid. The sulfonation of naphthalene with excess 96 wt % sulfuric acid at < 80°C gives > 85 wt % 1-naphthalenesulfonic acid (a-acid) the balance is mainly the 2-isomer (P-acid). An older German commercial process is based on the reaction of naphthalene with 96 wt % sulfuric acid at 20—50°C (13). The product can be used unpurifted to make dyestuff intermediates by nitration or can be sulfonated further. The sodium salt of 1-naphthalenesulfonic acid is required, for example, for the conversion of 1-naphthalenol (1-naphthol) by caustic fusion. In this case, the excess sulfuric acid first is separated by the addition of lime and is filtered to remove the insoluble calcium sulfate the filtrate is treated with sodium carbonate to precipitate calcium carbonate and leave the sodium l-naphthalenesulfonate/7J(9-/4-J7 in solution. The dry salt then is recovered, typically, by spray-drying the solution. 

Paint is one of the most common and widely used materials in home and building constmction and decoration (see Building materials). Its broad use comes from its abiHty to provide not only improved appearance and decoration but also protection of a substrate to which it is appHed. Evidence of the historical uses of paint goes back over 25,000 years to cave paintings found in Europe. The Bible describes pitch being used to coat and protect Noah s Ark. Over 10,000 years ago in the Middle East, various minerals and metals such as lime, siHca, copper and iron oxides, and chalk were mixed and reacted to produce many colors. Resins from plant sap and casein were also used. Over 2000 years ago in Asia, resins refined from insect secretions and sap from trees were used to make clear lacquers and varnishes (2). 

The reaction is completed after 6—8 h at 95°C volatiles, water, and some free phenol are removed by vacuum stripping up to 140—170°C. For resins requiring phenol in only trace amounts, such as epoxy hardeners, steam distillation or steam stripping may be used. Both water and free phenol affect the cure and final resin properties, which are monitored in routine quaHty control testing by gc. OxaHc acid (1—2 parts per 100 parts phenol) does not require neutralization because it decomposes to CO, CO2, and water furthermore, it produces milder reactions and low color. Sulfuric and sulfonic acids are strong catalysts and require neutralization with lime 0.1 parts of sulfuric acid per 100 parts of phenol are used. A continuous process for novolak resin production has been described (31,32). An alternative process for making novolaks without acid catalysis has also been reported (33), which uses a... 

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