Milk of lime

Brine Preparation. Sodium chloride solutions are occasionally available naturally but they are more often obtained by solution mining of salt deposits. Raw, near-saturated brines containing low concentrations of impurities such as magnesium and calcium salts, are purified to prevent scaling of processing equipment and contamination of the product. Some brines also contain significant amounts of sulfates (see Chemicals FROMBRINe). Brine is usually purified by a lime—soda treatment where the magnesium is precipitated with milk of lime (Ca(OH)2) and the calcium precipitated with soda ash. After separation from the precipitated impurities, the brine is sent to the ammonia absorbers. 

This carbon dioxide-free solution is usually treated in an external, weU-agitated liming tank called a "prelimer." Then the ammonium chloride reacts with milk of lime and the resultant ammonia gas is vented back to the distiller. Hot calcium chloride solution, containing residual ammonia in the form of ammonium hydroxide, flows back to a lower section of the distiller. Low pressure steam sweeps practically all of the ammonia out of the limed solution. The final solution, known as "distiller waste," contains calcium chloride, unreacted sodium chloride, and excess lime. It is diluted by the condensed steam and the water in which the lime was conveyed to the reaction. Distiller waste also contains inert soHds brought in with the lime. In some plants, calcium chloride [10045-52-4], CaCl, is recovered from part of this solution. Close control of the distillation process is requited in order to thoroughly strip carbon dioxide, avoid waste of lime, and achieve nearly complete ammonia recovery. The hot (56°C) mixture of wet ammonia and carbon dioxide leaving the top of the distiller is cooled to remove water vapor before being sent back to the ammonia absorber. 

Milk-of-lime is a dilute lime hydrate in aqueous suspension which has the consistency of milk. 

Recovering ammonia as a by-product from other processes accounted for less than 1% of the total U.S. ammonia production in 1987. The principal source of by-product ammonia is from the coking of coal. In the coking operation, about 15—20% of the nitrogen present in the coal is Hberated as ammonia and is recovered from the coke oven gas as ammonium sulfate, ammonia Hquor, and ammonium phosphates. The recovery product depends on the scmbbing medium employed, sulfuric acid, milk of lime, and phosphoric acid, respectively. Ammonium sulfate recovery by the so-called semidirect process, is most widely employed. 

In the semidirect process, (Fig. 23) the taw coke oven gas is cooled to condense tar and ammonia Hquor. The heavy layer, tar phase, is pumped to storage and the aqueous layer containing free and fixed ammonia is subsequendy processed in a stiH operation. Free ammonia is that which is in a form which readily dissociates by heat. Fixed ammonia is in a form which requites the presence of an alkaH, such as milk of lime, to effect the ammonia release. 

The Hquor is then treated with calcium hydroxide (milk of lime) which reacts with the fixed salts, mosdy ammonium chloride, to Hberate ammonia. The Hquor is regenerated in a steam stripping operation. 

Phosphatation. Phosphoric acid to give a concentration up to 400 mg/kg as P2O5 and calcium hydroxide as milk of lime or sugar solution of... 

Precipitated Calcium Carbonate. Precipitated calcium carbonate can be produced by several methods but only the carbonation process is commercially used in the United States. Limestone is calcined in a kiln to obtain carbon dioxide and quicklime. The quicklime is mixed with water to produce a milk-of-lime. Dry hydrated lime can also be used as a feedstock. Carbon dioxide gas is bubbled through the milk-of-lime in a reactor known as a carbonator. Gassing continues until the calcium hydroxide has been converted to the carbonate. The end point can be monitored chemically or by pH measurements. Reaction conditions determine the type of crystal, the size of particles, and the size distribution produced. 

Fig. 2. Diagram of a typical chlorohydrin reactor for manufacture of propylene oxide. M.O.L. = milk of lime. To convert kPa to mm Hg, multiply by 7.5.

Sulfide Ores ores. In the Zairian ores, cobalt sulfide as carroUite is mixed with chalcopyrite and chalcocite [21112-20-9]. For processing, the ore is finely ground and the sulfides are separated by flotation (qv) using frothers. The resulting products are leached with dilute sulfuric acid to give a copper—cobalt concentrate that is then used as a charge in an electrolytic cell to remove the copper. Because the electrolyte becomes enriched with cobalt, solution from the copper circuit is added to maintain a desirable copper concentration level. After several more steps to remove copper, iron, and aluminum, the solution is treated with milk of lime to precipitate the cobalt as the hydroxide. 

Quicklime, CaO, has a density range of approximately 55 to 75 Ib/cu ft, and a molecular weight of 56.08. A slurry for feeding, called milk of lime, can be prepared with up to 45 percent solids. Lime is only slightly soluble, and both lime dust and slurries are caustic in nature. A saturated solution of lime has a pH of about 12.4. 

Milk-of-lime transfer pumps should be of the open impeller centrifugal type. Pumps having an iron body and impeller with bronze trim are suitable for this purpose. Rubber-lined pumps with rubber-covered impellers are also frequently used. Makeup tanks are usually provided ahead of centrifugal pumps to ensure a flooded suction at all times. Plating out of lime is minimized by the use of soft water in the makeup tank and slurry recirculation. Turbine pumps and eductors should be avoided in transferring milk of lime because of scaling problems. 

The lime feeding system may be controlled by an instrumentation system integrating both plant flow and pH of the wastewater after lime addition. However, it should be recognized that pH probes require daily maintenance in this application to monitor the pH accurately. Deposits tend to build up on the probe and necessitate frequent maintenance. The low pH lime treatment systems (pH 9.5 to 10.0) can be more readily adapted to this method of control than high-lime treatment systems (pH 11.0 or greater) because less maintenance of the pH equipment is required. In a close-loop pH-flow control system, milk of lime is prepared on a batch basis and... 

Calcium carbonate is manufactured by bubbling carbon dioxide through milk of lime suspension in a carbonator , according to... 

Ultimately, pollution can only be avoided by complete removal of SO2 from the effluent gases, but this council of perfection is both technologically and economically unattainable. Many processes are available to reduce the SO2 concentration to very low figures, but the vast scale of power generation and domestic heating by coal and oil still results in substantial emission. SO2 can be removed by scrubbing with a slurry of milk of lime , CafOH) . Alternatively, partial reduction to H2S using natural gas (CH4), naphtlia or coal, followed by catalytic conversion to elemental sulfur by the Claus process can be used ... 

It is possible, however, that camphene hydrochloride is not a uniform body, but that some of the terpene suffers some rearrangement in the molecule by the action of hydrochloric acid, and that the hydrochloride consists of a mixture of a-camphene hydrochloride and /8-camphene hydrochloride there is, however, no evidence to suggest that camphene itwlf is a mixture of two terpenes, so that the two camphenes are not known to exist. Aschan obtained an alcohol, camphene hydrate, by acting on camphene hydrochloride with milk of lime, a reagent which does not produce molecular rearrangement in the terpene nucleus. 

In the same way bornyl and isobornyl chlorides react with milk of lime. But, whereas bornyl chloride gives an almost quantitative yield of... 

If milk of lime be used as the regenerating reagent, a different sesquiterpene results, which has the following characters —... 

Orangesamenol, n. orange-seed oil. orangieren, v.t. Calico) treat with milk of lime. Ord, abbrev. of Ordnung. 

The lime application and settling process treatment consists of adding a milk of lime slurry to the wastewater to precipitate the hydroxide of the heavy metals and reduce dissolved sulfate concentrations through the formation of gypsum. Sufficient lime is needed to adjust the pH to between 10 and 11.5. Also, settling may have to be aided by adding small quantities of organic polyelectrolytes. 

Preparation of Inulin. Comminute the tubers or roots in a food chopper or similar appliance and express the juice with a tincture press, using, if necessary, a small portion of water to complete the extraction. Heat the juice to 60-70° and add milk of lime to about pH 8. Filter and adjust the pH to 7 with oxalic acid. Heat to 70-80°, add activated carbon and filter. Allow the filtrate to stand quiescent overnight, during which time the inulin separates in the form of small spheroids. The yield may be increased by freezing the solution and allowing it to thaw at a low temperature. Filter and wash the inulin with abundant quantities of cold water. 

Hydrated hydraulic limes, 15 55 Hydrated lime(s), 15 28, 61 aquaculture application, 3 207 high surface area, 15 55 production of milk of lime from, 15 56 quality control for, 15 70 reactions, 15 45... 

A severe thrips infestation occurred in 1953 in cacao plantations in the Comal-calco area of the state of Tabasco, Mexico. The trees suffered a nearly total defoliation. Control was reported to have been obtained by applications of aqueous solutions of Deenate 75W (DDT 75%) according to the formula Deenate 150 gram, Spreader Sticker 15 cc., and water 100 liters. Bordeaux mixture and milk of lime have also been reported as giving good control in some localities. 

Mara pigments inorg chem A group of five pigments produced when milk of lime is added to a ferrous sulfate solution, and the precipitate is calcined color is controlled by calcination temperature to give yellow, orange, brown, red, or violet. marz. pig-msns ... 

Quinine Sulphate. 90-100 g of cinchona bark is ground up with 250 cc of milk of lime. Evaporate to dryness on water bath, cool, and powder. Shake this powdered residue with 200 cc of chloroform and allow to stand in a flask for 12 hours. Filter and wash with chloroform. 

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