Slaked lime

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Slaked lime

Postby chiggerbit » Fri Apr 25, 2008 12:35 am

Posting this Wiki link quickly. Will come back to it later:

Calcium hydroxide, traditionally called slaked lime, hydrated lime, or pickling lime, is a chemical compound with the chemical formula Ca(OH)2. It is a colourless crystal or white powder, and is obtained when calcium oxide (called lime or quicklime) is mixed, or "slaked" with water. It can also be precipitated by mixing an aqueous solution of calcium chloride and an aqueous solution of sodium hydroxide. The name of the natural mineral is portlandite.

When heated to 512°C, the partial pressure of water in equilibrium with calcium hydroxide reaches 101 kPa and decomposes into calcium oxide and water.[1] A suspension of fine calcium hydroxide particles in water is called milk of lime. The solution is called lime water and is a medium strength base that reacts violently with acids and attacks many metals in presence of water. It turns milky if carbon dioxide is passed through, due to precipitation of calcium carbonate....

....Because of its strong basic properties, calcium hydroxide has many and varied uses:

A flocculant, in water and sewage treatment and improvement of acid soils
An ingredient in whitewash, mortar, and plaster
An alkali used as a lye substitute in no-lye hair relaxers
A chemical depilatory agent found in Nair
An ingredient in baby formula milk
A chemical reagent
In the reef aquarium hobby for adding bio-available calcium in solution for calcium-using animals such as algae, snails, hard tube worms, and Corals (often referred to as Kalkwasser mix)
In the tanning industry for neutralization of extra acid
In the petroleum refining industry for the manufacture of additives to oils (salicatic, sulphatic, fenatic)
In the chemical industry for manufacture of calcium stearate
In the food industry for processing water (for alcoholic and soft drinks)
For clearing a brine of carbonates of calcium and magnesium in the manufacture of salt for food and pharmacopoeia
In Native American and Latin American cooking, calcium hydroxide is called "cal". Corn cooked with cal becomes nixtamal which significantly increases its nutrition value, and is also considered tastier and easier to digest.
In chewing Betel nut or coca leaves, calcium hydroxide is usually chewed alongside to keep the alkaloid stimulants chemically available for absorption by the body
Similarly, Native Americans traditionally chewed tobacco leaves with calcium hydroxide derived from burnt shells to enhance the effects
A filler
In the petrochemical industry for manufacturing solid oil of various marks
In the manufacture of brake pads
In the manufacture of ebonite
For preparation of dry mixes for painting and decorating
In manufacturing mixes for pesticides
In manufacturing a drug called "Polikar" for fighting decay (due to fungus) of fruits and vegetables during storage
In Dentistry, it is used as dressing in paste form used for anti-microbial effect during a dental root canal procedure. Calcium hydroxide is known to have a strong anti-microbial effect and is a bone-regeneration stimulant.[2]

[edit] Health risks
An overexposure to calcium hydroxide can have life threatening effects:

Difficulty in breathing[citation needed]
Internal bleeding[citation needed]
Hypotension[citation needed]
Skeletal muscle paralysis, interference with actin-myosin system.
An increase in blood pH, which is damaging to the internal organs.[citation needed]
Calcium Hydroxide is also a cancer suspect agent
.[citation needed]...
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Postby chiggerbit » Fri Apr 25, 2008 12:53 am

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Postby chiggerbit » Fri Apr 25, 2008 1:06 am

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Postby chiggerbit » Mon Apr 28, 2008 1:13 pm

Ok, the reason I was searching on slaked lime was becuse I found directions for storing eggs for long periods of time in a very old cookbook of mine, and the directions involved slaked lime. I could take pics of the directions, but I found this on the web:

Home Preseration Of Eggs

The housewife who desires to run her household on an economical basis will not depend entirely on eggs that are commercially stored, but will take advantage of one of the many methods by which eggs may be successfully kept in the home. By being prudent in this matter, she will be prepared to supply her family with this commodity at times when the market price is high.

As many as twenty household methods have been tried out for the preserving of eggs, but each one is based on the theory that decay is hindered when the shell is covered with some substance that renders it air-tight and prevents evaporation or the entrance of bacteria and mold. Among the methods that have met with the most success are burying eggs in oats, bran, or salt; rubbing them with fat; dipping them in melted paraffin; covering them with varnish or shellac; and putting them down in lime water or in a solution of water glass.

No matter which of these methods is adopted, however, it will be well to note that only eggs laid in April, May, or June should be used for storage purposes, as these are the best ones laid during the year; also, that the eggs should always be packed with the small end down, because the yolk will not settle toward the small end so readily as toward the large end or the side.

Of these various ways of preserving eggs in the home, probably the oldest method is that of packing the eggs in oats, bran, or salt. This method is fairly effective, but the eggs preserved by it do not keep so long as eggs preserved by other methods, nor is their quality so good. Preserving eggs by completely covering the shells with fat, vaseline, paraffin, varnish, or other substance that will exclude the air but not impart flavor to the eggs, proves a more satisfactory method so far as the eggs are concerned, but it requires more time and handling. To assist in their preservation, eggs are sometimes immersed in boiling water for 12 to 15 seconds. This process, which causes the white to harden slightly just inside of the shell, keeps the eggs fairly well, but it is rather difficult to accomplish, as the least overcooking renders the egg unfit for use as a raw egg.

As a result of many trials, it has been found that putting eggs down in the various solutions that are used for this purpose is the most effective way of preserving them under home conditions, provided, of course, the solutions in which the eggs are immersed do not flavor the eggs. Therefore, to assist the housewife, detailed directions for using lime water and water glass for this purpose are here given.

PRESERVATION WITH LIMEWATER.--To prepare limewater for the preservation of eggs, dissolve 1 pound or 1 pint of salt and 1 quart of finely slaked lime in 3 gallons of water, stir the solution at frequent intervals for a day or two, and then allow the liquid to settle. Place the eggs in tall stone crocks or kegs with their pointed ends turned down, filling the receptacles to within a few inches of the top. Pour the clear limewater over the eggs so arranged, allowing it to rise an inch or two above the top layer. Then stand the vessel in a cool place where the temperature will not exceed 50 degrees Fahrenheit. Eggs so treated will keep for at least 6 or 8 months. The only objection to this plan is that the eggs preserved by it sometimes acquire a slight lime taste.

PRESERVATION WITH WATER GLASS.--Putting eggs down in a solution of water glass is without doubt the most satisfactory method of storing them in the home. So effective does this method prove that the housewife who has a convenient and proper storage room should not fail to take advantage of this way of laying up a supply of eggs.

The commercial form of water glass is usually a mixture of potassium and sodium silicate, which, besides being cheaper than that which is chemically pure, is the kind that is preferred for the purpose of preserving eggs. A good quality of it either in a sirup-like solution or in the form of a powder retails in drug or grocery stores for about 10 cents a pound. To make a solution of the desired strength to preserve eggs satisfactorily, dissolve 1 part of water glass in 7 parts of warm water that has first been boiled to drive off bacteria, mold, spores, etc. One quart of water glass will make sufficient solution to cover about 12 dozen eggs. With the solution thoroughly mixed, it is ready to pour over the eggs.

In selecting eggs for the purpose of storing, be careful to choose only those which are clean, fresh, and perfectly sound, and, if possible, infertile. It is advisable not to wash them before they are put into the preservative, for they will keep better if their bloom is not removed. Place the eggs in receptacles in the manner explained for preserving eggs in limewater, and over them pour the water-glass solution until they are all covered. If the eggs so prepared are stored in a cool place, they will keep as long as those preserved in limewater; besides, there will be no danger of their acquiring any foreign flavor.
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Postby chiggerbit » Mon Apr 28, 2008 1:50 pm

Water Glass. What an interesting compound. It always fascinates me that what the old-timers took for granted most of us have no clue about today. Where can this stuff even be purchased today? It used to be available at the local drug stores, hardware stores, even grocery stores. Wiki mentions this about water glass:

Sodium silicate, also known as water glass or liquid glass, available in aqueous solution and in solid form, is a compound used in cements, passive fire protection, refractories, textile and lumber processing....

....Sodium carbonate and silicon dioxide react when molten to form sodium silicate and carbon dioxide.

Sodium silicate is a white solid that is soluble in water, producing an alkaline solution. There are many kinds of this compound, including sodium orthosilicate, Na4SiO4; sodium metasilicate, Na2SiO3; sodium polysilicate, (Na2SiO3)n; sodium pyrosilicate, Na6Si2O7, and others. All are glassy, colourless and dissolve in water.

Sodium silicate is stable in neutral and alkaline solutions. In acidic solutions, the silicate ion reacts with hydrogen ions to form silicic acid, which when heated and roasted forms silica gel, a hard, glassy substance.

Sodium silicate is used, along with magnesium silicate, in muffler repair and fitting paste. When dissolved in water, both sodium silicate, and magnesium silicate form a thick paste that is easy to apply. When the exhaust system of an internal combustion engine heats up to its operating temperature, the heat drives out all of the excess water from the paste. The silicate compounds that are left over have glass-like properties, making a somewhat permanent, brittle repair.

Automotive repair

Sodium silicate can be used to seal leaks at the head gasket. A common use is when an alloy cylinder head motor is left sitting for extended periods or the coolant is not changed at proper intervals, electrolysis can "eat out" sections of the head causing the gasket to fail.

Rather than pull the head, a jar of "liquid glass" is poured into the radiator and allowed to circulate. The Waterglass is injected via the radiator water into the hotspot at the motor. This technique works because at 210 - 220 °F the sodium silicate loses water molecules to form a very powerful sealant that will not re-melt below 1500 °F. This approach is often used by disreputable used-car salespersons to disguise a leaking head gasket.

A sodium silicate repair of a leaking head gasket can hold for up to two years and even longer in some cases. The effect will be almost instant, and steam from the radiator water will stop coming out the exhaust within minutes of application. This repair only works with water to cylinder or water to Air applications and where the sodium silicate reaches the "conversion" temperature of 210 - 220 °F.

[edit] Cement uses
Sodium silicate has been widely used as a general purpose cement, but especially for applications involving cementing objects exposed to heat or fire. For example, sodium silicate has been provided in home first-aid kits and used in medical practice as a glue for holding human skin together at surface cuts. It has also been used as a general purpose paper cement.

One common example of its use as a paper cement was for producing paper cartridges for black powder revolvers produced by Colt's Manufacturing Company during the period from 1851 until 1873, especially during the American Civil War. Sodium silicate was used to seal combustible nitrated paper together to form a conical paper cartridge to hold the black powder, as well as to cement the lead ball or conical bullet into the open end of the paper cartridge. Such sodium silicate cemented paper cartridges were inserted into the cylinders of revolvers, thereby speeding the reloading of cap and ball black powder revolvers. This use largely ended with the introduction of Colt revolvers employing brass-cased cartridges starting in 1873.

When used as a paper cement, the tendency is for the sodium silicate joint eventually to crack within a few years, at which point it no longer holds the paper surfaces cemented together.

[edit] Food preservation
Sodium silicate was also used as an egg preservation agent in the early 20th Century with large success. When fresh eggs are immersed in it, bacteria which cause the eggs to spoil are kept out and water is kept in. Eggs can be kept fresh using this method for up to nine months. When boiling eggs preserved this way, it is well advised to pin-prick the egg to allow steam to escape because the shell is no longer porous.

An article in The Mother Earth News offers actual test results for this and other methods of preservation. LINK

[edit] Timber treatment
The use of sodium silicate as a timber treatment for pressure-treated wood actually began some time in the 19th century. It is suggested that that more costly "silicate of potash" (potassium silicate) may also be used, in "Handy Farm Devices and How to Make Them" by Rolfe Cobleigh, published in 1910. Since 1998 scientists have researched methods for rendering sodium silicate insoluble once the lumber has been treated with it. With or without the additional process, treating wood with sodium silicate preserves wood from insects and possesses some flame-retardant properties.

[edit] Concrete and general masonry treatment
Concrete treated with a sodium silicate solution helps to significantly reduce porosity in most masonry products such as concrete, stucco, plasters. A chemical reaction occurs with the excess Ca(OH)2 in the concrete that permanently binds the silicates with the surface making them far more wearable and water repellent. It is generally advised to apply only after initial cure has taken place (7 days or so depending on conditions). These coatings are known as silicate mineral paint.

[edit] Passive fire protection ("PFP")
Sodium silicates are inherently intumescent. They come in prill (solid beads) form, as well as the liquid, water glass. The solid sheet form (Palusol) must be waterproofed to ensure longterm passive fire protection. Standard, solid, bead form sodium silicates have been used as aggregate within silicone rubber to manufacture plastic pipe firestop devices. The silicone rubber was insufficient waterproofing to preserve the intumescing function and the products had to be recalled, which is problematic for firestops that are concealed behind drywall in buildings. Pastes for caulking purposes are likewise unstable even for very short periods of time. This too has resulted in recalls and even litigation. Only 3M's "Expantrol" version, which has an external heat treatment that helps to seal the outer surface, as part of its process standard, has achieved sufficient longevity to qualify for DIBt [1] approvals for use in firestopping. Not unlike other intumescents, sodium silicate, both in bead form and in liquid form are inherently endothermic, due to liquid water in the water glass and hydrates in the prill form. The absence of mandatory ageing tests, whereby PFP systems are made to undergo system performance tests after the ageing and humidity exposures are at the root of the continued availability in North America in PFP products that can become inoperable within weeks of installation. Indiscriminate use of sodium silicates without proper waterproofing measures are contributors to the malaise. When sodium silicates are adequately protected, they function extremely well and reliably over long periods of time. Evidence of this can be seen in the many DIBt approvals for plastic pipe firestop devices using Palusol, which use waterproofed sodium silicate sheets.

[edit] Refractory use
Water glass is a useful binder of solids, such as vermiculite and perlite. When blended with the aforementioned lightweight aggregates, water glass can be used to make hard, high-temperature insulation boards used for refractories, passive fire protection and high temperature insulations, such as moulded pipe insulation applications. When mixed with finely divided mineral powders, such as vermiculite dust (which is common scrap from the exfoliation process), one can produce high temperature adhesives. The intumescence disappears in the presence of finely divided mineral dust, whereby the waterglass becomes a mere matrix. Waterglass is inexpensive and abundantly available, which makes its use popular in many refractory applications.

[edit] Water Treatment
Water glass is used as a water treatment in waste water treatment plants. Waterglass will bind to heavier molecules and drag them out of the water.

[edit] Magic Crystals
Water glass was used in the magic crystal garden toys from the 1980's. When waterglass was combined with a selection of different metals in solution, the waterglass would cause the metals to precipitate. Each metal would precipitate separately causing a different color stalagmite.

An early mention of crystals of metallic salts forming a "chemical garden" in sodium silicate is found in the 1946 Modern Mechanix magazine [2]. This results in very colorful gardens -- much more than shown in the illustrations. Use caution with the metal salts if you do this, some are dangerous to people and animals if swallowed.
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Postby chiggerbit » Mon Apr 28, 2008 1:55 pm

This reminds me that my now-ex son-in-law, who was from Tunisia, told me that one of the most popular Western tv shows over there was the old MacGyver show:

"....The series revolved around Angus MacGyver (known to his friends as MacGyver or "Mac") who favors brain over brawn in order to solve desperate problems. MacGyver's main asset is his practical application of scientific knowledge and inventive use of common items—along with his ever-present Swiss Army knife and duct tape. The clever solutions MacGyver implemented to seemingly intractable problems—often in life-or-death situations requiring him to improvise complex devices in a matter of minutes—were a major attraction of the show, which was praised for generating interest in the applied sciences, and particularly engineering[1] as well as providing entertaining story lines. All of MacGyver's exploits on the show were ostensibly vetted to be based on real scientific principles (even though, the creators acknowledged, in real life one would have to be extraordinarily lucky for most of MacGyver's ideas to succeed). In the few cases where MacGyver used household chemicals to create poisons, explosives or other things deemed too dangerous to be accurately described for public consumption, details were intentionally altered or left vague.

The use of ordinary household items to jury rig devices shows an influence from The A-Team (though MacGyver eschewed firearms). The idea has entered United States popular culture; such constructions are referred to as "MacGyverisms" (a term first used in episode 3 of season 2, "Twice Stung")....."
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Postby RomanyX » Fri Aug 01, 2008 4:41 am

chiggerbit wrote:Water Glass. What an interesting compound. It always fascinates me that what the old-timers took for granted most of us have no clue about today. Where can this stuff even be purchased today?

If you're in the US, you can try this place.

I've seen it on eBay from time to time, as well.
Oh Perfect Masters,
They thrive on disasters;
They all look so harmless
'Til they find their way up there...
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Postby chiggerbit » Sat Aug 02, 2008 12:06 pm

What an interesting site, Romany!

On the "W" page:

Wood Meal

Extremely fine, light-tan flour, much-much finer than sawdust

Used as a soil extender, as filler in a plastic resin matrix, animal feed filler, oil and water solidification, toilet seats, decking, marina products, and automotive components. Some other interesting uses of wood meal include cleaning of furs where it is a mild abrasive and oil absorbent, it is also an abrasive in soaps - especially those used by mechanics, and relatively coarse wood meal is used in silverware cleaners. Other uses include doorknobs, ornaments, and molded furniture parts.
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Postby chiggerbit » Mon Apr 27, 2009 11:35 pm

For Release: June 30, 2008

FTC Challenges Carlyle Partners’ Purchase of INEOS’s Sodium Silicate Businesses
Companies Required to Sell Carlyle’s Sodium Silicate Plant in Utica, Illinois

The Federal Trade Commission today issued a complaint charging that Carlyle Partners IV, L.P.’s (Carlyle) proposed acquisition of the world-wide sodium silicate and silicas business of INEOS Group Limited (INEOS) would be anticompetitive and in violation of the antitrust laws. Carlyle owns PQ Corporation (PQ), and the transaction as proposed would therefore combine PQ – the largest sodium silicate producer and seller in the highly concentrated Midwest region of the United States – with INEOS, its third-largest competitor.

To remedy the alleged anticompetitive effects of the transaction, the companies have entered into a consent agreement with the Commission that requires them to sell PQ’s sodium silicate plant and businesses in Utica, Illinois, to an FTC-approved buyer. The order also requires the companies to license all of the intellectual property related to sodium silicate product at the Utica plant.

“The consent agreement underscores that even when the to-be-acquired firm is relatively small, the Commission has concerns when the market is highly concentrated and characterized by an absence of strong competition,” said Jeffrey Schmidt, Director of the FTC’s Bureau of Competition.

The Relevant Product Market

Both PQ and INEOS participate in the sodium silicate market world-wide, and PQ is the largest sodium silicate producer in the United States. Sodium silicate has a variety of direct uses and also is used in the production of downstream silicate derivatives, also known as silicas. It is typically sold in an aqueous solution that is 65 percent water; sodium silicate markets exhibit strong regional characteristics because of high transportation costs relative to the value of the product. Because there are no close chemical substitutes for sodium silicate, the FTC contends that other products do not constrain its pricing.

The Commission’s Complaint

According to the Commission’s complaint, the proposed acquisition would be anticompetitive and violate Section 5 of the FTC Act and Section 7 of the Clayton Act as amended, in that it would combine the largest firm in the Midwest U.S. sodium silicate market, PQ, with the third-largest firm in that market, INEOS. Currently PQ has 50 percent of the market and INEOS has 12 percent of the market. The FTC contends that in addition to reducing direct competition between the two companies, the proposed acquisition could lead to coordination among competing firms in the sodium silicate market.

The Midwest market for sodium silicate already is conducive to such coordination due to several structural features, including the facts that sodium silicate is a homogenous product, pricing information is readily available, and competitors recognize that the market is essentially a duopoly in which the top two firms, PQ and Occidental, operate interdependently. Based on concentration levels and competitive concerns, the complaint states that the acquisition could make coordinated interaction between the competing firms more likely, leading to higher prices for sodium silicate. Finally, the complaint alleges that entry into the relevant market would not be timely, likely, or sufficient to deter the acquisition’s anticompetitive impacts.

Terms of the Consent Order

The Commission’s consent order is designed to remedy the alleged anticompetitive effects of the acquisition. The order requires Carlyle to divest PQ’s sodium silicate plant in Utica, Illinois, to Oak Hill Acquisition Company, LLC (Oak Hill), or another FTC-approved buyer if Oak Hill is later found to be an unacceptable acquirer, within five days of acquiring INEOS. Oak Hill is a new firm created for the purpose of acquiring the Utica plant. However, its principal owner has been involved in many industrial investments over the past 25 years in the chemical, software, telecom, construction, real estate, and energy areas.

The consent order contains several other terms to ensure that the sale of the Utica plant to Oak Hill is successful and that competition continues within the market. For example, in addition to allowing the Commission to require Carlyle to find another buyer if Oak Hill is found to be unacceptable, it requires Carlyle and INEOS to make available to any buyer the necessary personnel, assistance, and training to enable it to successfully operate the Utica plant for two years after its sale.

In addition, the companies must enter into an employee services agreement covering certain union employees at the Utica plant to ensure that they can keep their jobs after the sale. Next, the order allows the FTC to appoint an interim monitor to ensure that the companies comply with their obligations following the divestiture, as well as a divestiture trustee if PQ fails to comply fully with the terms of the order. Finally, the order requires the companies to notify the FTC of any change in their corporate structures that may affect compliance with its terms. The order will expire in 10 years.

The Commission vote to accept the complaint and proposed consent order was 4-0. The FTC will publish an announcement regarding the agreement in the Federal Register shortly.

The agreement will be subject to public comment for 30 days, beginning today and continuing through July 29, 2008, after which the Commission will decide whether to make it final. Comments should be addressed to the FTC, Office of the Secretary, Room H-135, 600 Pennsylvania Avenue, N.W., Washington, D.C. 20580. The FTC is requesting that any comment filed in paper form near the end of the public comment period be sent by courier or overnight service, if possible, because U.S. postal mail in the Washington area and at the Commission is subject to delay due to heightened security precautions. Comments also can be filed electronically using the Commission’s Web site.

NOTE: A consent agreement is for settlement purposes only and does not constitute an admission of a law violation. When the Commission issues a consent order on a final basis, it carries the force of law with respect to future actions. Each violation of such an order may result in a civil penalty of $11,000.

Copies of the Commission’s complaint, consent order, and analysis to aid public comment are available from the FTC's web site at and the FTC's Consumer Response Center, Room 130, 600 Pennsylvania Avenue, N.W., Washington, D.C. 20580. The FTC’s Bureau of Competition works with the Bureau of Economics to investigate alleged anticompetitive business practices and, when appropriate, recommends that the Commission take law enforcement action. To inform the Bureau about particular business practices, call 202-326-3300, send an e-mail to, or write to the Office of Policy and Coordination, Room 394, Bureau of Competition, Federal Trade Commission, 600 Pennsylvania Ave, N.W., Washington, DC 20580. To learn more about the Bureau of Competition, read “Competition Counts” at
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