What is litharge and what are its uses?


GRAVITA
Litharge
Beside of medicine, it is still used for manufacturing white lead paint, lead soap, cosolvent in metallurgy, paint driers, ceramic materials, rubber vulcanization accelerators, pesticides, and so on. Medicinally it is usually used externally. And pharmacological studies have confirmed that it could kill skin fungus, reduce inflammation, protect ulcer surface, reduce mucus secretion, etc. Actually its health benefits on fading dark spots has been discovered for so long – Tang Ben Cao (Tang Materia Medica) says that it can be used as scar removing creams and the Shen Nong Ben Cao Jing Shu (Commentary on ‘Shen Nong’s Classic of the Materia Medica) claims that it is good at healing metal-inflicted wound and removing acne scars from face. Accordingly, today many ancient beauty recipes still exist. For instance, the formula of Yu Rong San (fair face powder) alone, there are a few different versions. So to speak, it is one of the best dark spots removers you can find these days.


 Modern pharmacological actions of lead oxide

1. In vitro 2% litharge cream inhibits Trichophyton, Trichophyton violaceum, Trichophyton rubrum and some spore bacteria;
2. In vitro 4% litharge cream shows inhibition on Epidermophyton floccosum, trichophyton gypseum, Trichophyton schoenleinii and its Mongolia variant, and so on;
3. Its water extract (1:3) in vitro has different degrees of inhibition on a variety of skin fungi;
4. For external use it can reduce inflammation;
5. 1:3 infusion in vitro shows inhibition on skin fungi like Trichophyton violaceum and spore bacteria.

Selected litharge formulas on herbal remedies

According to Quan Guo Zhong Cao Yao Hui Bian (National Collection of Chinese Herbal Drugs), it is salty and acrid in flavor and neutral and poisonous in nature. Prime functions include eliminating dampness, killing parasites, and healing sores. And primary litharge uses and indications are eczema, scabies, ringworm, armpit odor, and non-healing burst sores. It is usually used externally only in the forms of powder or paste.


1. Tuo Seng Wan from Liang Peng Hui Ji (Close Friends’ Collection). It is combined with Huang La (beeswax), Ku Fan (dried alum), Xiong Huang (realgar), etc. to treat ruptured scrofula, early phase of carbuncle all over the body, stubborn ecthyma, anal fistula, etc.

2. Tuo Seng San from Dong Tian Ao Zhi (Profound Essence of the Heaven). It is formulated with Qing Fen (calomel), Shi Gao (Gypsum), and alum to cure athlete’s foot.

3. Shen Xiao Wan from Yu Ju Shi Xuan Qi Fang (odd-ingredient prescriptions chosen by lay Buddhist Yu). It is made into pills to consumptive thirst.

4. Tuo Seng San from Pu Ji Fang (Prescriptions of Universal Relief). It is put together with Pu Huang (cattail pollen), Huang Bai (Amur Cork Tree), and Gan Cao (Licorice Root) for the treatment of tongue and mouth sores.

5. Yu Rong San from Qian Jin Yao Fang (Thousand Golden Essential Prescriptions). It is used along with Bai Fu Zi (Typhonium Rhizome), Mu Li (Oyster Shell), Fu Ling (Poria), and Chuan Xiong (Szechuan Lovage Root) for moistening face and removing acne scars from face.

Litharge side effects and contraindications
Litharge is poisonous and oral administration is allowed only under the supervision of a physician. Long term use of it can result in lead poisoning. So, caution should be taken when taking it orally and overdose should be avoided by all means. In addition, it shouldn’t be used in the weak, pregnant women, and children.
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What is lead powder and its Applications/Uses?


GRAVITA
Lead Powder

Lead powder is often produced by dispersing melted lead. Drops of molten lead are atomized using a jet of high temperature gas. The lead can be introduced into the gas stream in the same direction as the gas flow, by use of an annular nozzle, or the molten lead can be dripped into a perpendicular stream of gas. The first method produces finer lead powder and is therefore more useful in certain applications such as lead bases anti-friction lubricants.
In a typical manufacturing process the lead is melted in a crucible, the liquid metal flows out of an hole, of precise dimensions, in the bottom of the crucible and more molten metal is added to maintain a constant level – this will ensure a constant rate of flow through the hole in the bottom of the crucible. The metal flows into a gas jet that has been heated to about 200oC and is dispersed into small particles up to a few microns in size.
Lead powder can also be produced by electrolysis, though this is not that important a method. Thermolysis, using oleic acid produces very small particles that are suitable for lubricants.
Lead oxide; also know as litharge lead or Lead Monoxide is another form of lead that is produced as a red or yellow crystalline powder. Litharge is produced by contacting molten lead with air. Lead Monoxide is obtained as a crystallized or amorphous power.

Applications

Oil and gas exploration, Radiological Medical protective clothing, Industrial X-ray shielding, Golf club manufacturing, Anti-friction products.
Powered lead, powdered Babbitt and lead oxide have been used in lubricating grease, to reduce or eliminate wear. Lead powder is also used as the basis for some corrosion resistant paints. Lead oxides are used in producing fine “crystal glass” and “flint glass” of a high index of refraction for achromatic lenses.

Powdered Lead in Golf clubs
Custom golf club makers use powdered lead to balance and weight the clubs. There is typically a cavity int head, accessible through a small hole sealed with a screw. Swing weight can be adjusted by removing this screw, adding a measured amount of powdered lead and replacing and securing the screw with epoxy.



Lead protective clothing

Lead powder incorporated into plastics is used to form sheets of Lead loaded plastic. This is used to make radiation protective clothing and aprons for the medical, scientific and nuclear industries. Lead loaded plastic is also used to make sound insulating barriers.



Lead powder in weapons
In the law enforcement shotgun rounds containing powdered lead are called breaching rounds. They are used on door hinges and handles to gain entry. Generally used by drug, warrant and swat teams. Powdered lead is used to minimize harm to individuals.


Weighted-knuckle gloves, also called sap gloves, are a type of weapon used in hand to hand combat. They consist of a pair of ordinary looking gloves usually made of leather or a synthetic material, with powdered lead sewn into a special pouch covering the knuckles, fingers and the back of the hand. They are primarily used by security professions and private citizens for self-defense.

Lead Powder in the electronics industry
Highly densified, polycrystalline photoconductors can be made by hot-pressing powdered lead monoxide. Such photoconductors will exhibit increased absorption of radiation, increased signal-to-noise ratios, and improved spatial frequency responses.



Lead Powder is also used for the preparation of pressed and bonded sputtering targets and in Chemical Vapor Deposition (CVD) systems.




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What is Red Lead And its Applications/Uses?


GRAVITA
Red Lead (Pb304 or 2PbO, PbO2) is soft orange and red colored powder. It is a useful ingredient for the storage battery, glass & ceramic industry and it occupies an important place in the Paint Industry for its rust inhibiting character. It is virtually insoluble in water and alcohol. However, it is soluble in the hydrochloric acid present in the stomach, therefore it is toxic when ingested. It dissolves in hydrochloric acid, glacial acetic acid, and a diluted mixture of nitric acid and hydrogen peroxide.
Red Lead

RED LEAD
Red Lead is used to a certain extent in the ceramics and glass, paints and pigments and explosives industries. Waldies Griffin brand Red Lead Non-Setting is a highly superior quality product and is the market leader.
Waldies also produces Red Lead Ordinary conforming to IS :57-1989 Type A and B. This formula corresponds to a PbO2 content significantly lower than 34.0% dependent upon the particular application in which they are to be used.
The material specifications of both Red Lead Ordinary & Red Lead Nonsetting are available in the datasheets attached above.

What is Red Lead Ordinary?
Red Lead Ordinary appears in a vibrant orange to red brick colored pigment which had a chemical property to be able to get dissolved in acetic acid and completely insoluble in water and ethanol. The leading red lead manufacturer in India employs reverberatory furnace to manufacture it by heating lead monoxide at 500°C in the presence of air.
Red lead ordinary has a relatively lower specific gravity, water and acid absorption rate (mg/gm) than red lead setting.  It is mostly used in ballistic modifiers for propellants of high-energy, ceramic glazes, in rubber adhesives and also in foam coatings used in X-rays as a radiation shield.

Applications

  • ·        Storage battery: Red lead is used in the production of positive plates/tubular plates.
  • ·        Paints: In ready mixed priming paints to be used within 24 hours of mixing.
  • ·        Paint Industry: Red lead is the most highly rated primer for the protection of ferrous metal surfaces for its rust inhibiting characters.
  • ·        Glass and Ceramics:In lead glass, glazes and other ceramics materials red lead is most widely used after litharge.
  • ·        Rubber and plastics: Red lead acts basically as an activator and vulcanizing agent as well as an inorganic colouring agent for natural and synthetic rubber and plastics.


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What is Lead Sheet And Its Applications/Uses?


GRAVITA

Lead sheets can be easily bent, shaped and formed for use in many applications. Commonly used medical radiation construction projects, sheet lead can be built into walls, doors and frames to protect medical personnel from gamma rays. It can also be used to stop radiation leakage from cut-outs and penetrations in lead-lined walls.
Sheet lead is also very effective for waterproofing, soundproofing, and isolating/dampening mechanical vibration. It is highly resistant to environmental and chemical corrosion, and so can be used in nearly any indoor or outdoor application. Lead sheeting is exceptionally versatile and easy to work with, allowing it to be bent, shaped, and cut to suit all applications, with no special tools required.

Lead Sheet
We offer a wide range of lead sheeting from 1/32 inch to 1 inch thicknesses to meet the demands of any application. Walls, doors, window frames, and more can have lead sheet built into, or added to, them for effective shielding protection.
Sheet lead is also used in our lead lined drywall and lead lined plywood. These products offer the same shielding protection as stand alone lead sheets, with far greater structural strength.
Radiation Protection Products uses only the purest lead available for our sheeting. Absolutely no refining takes place at our facility, making us one of the cleanest, most environmentally friendly radiation shielding providers in the industry, while providing you with the highest quality sheet lead available.

Four Applications Using Lead Sheet

Roofing/Flashing – Lead sheet offers flexibility and longevity. Unlike other materials, a sheet of lead can be securely dressed around penetrations and joints. In fact, this is the only material that provides adequate protection in these areas from water damage. Lead also handles temperature fluctuations; it is malleable, preventing cracks; and it will outlast other materials by up to ten times.



Soundproofing – Noise is a major challenge for many industries. Recent studies have found that high level noises from machinery and industrial equipment create stress for employees and can lead to permanent hearing damage. Accidents can occur if workers are unable to hear warning signals due to excessive noise. With lead sheets, sound waves are either absorbed, dampened, or blocked. For optimal results, the lead must have the appropriate weight per square foot of barrier. For blocking out sound over a wider range, the lead should be limp, or soft, as opposed to rigid.



Radiation Shielding – Lead sheet is commonly used to shield healthcare workers from radiation. For instance, during medical or dental x-rays, lead lined walls and leaded glass create a barrier between the x-ray machine and the x-ray technician for protection against radiation.


Waterproofing – In the building industry, underground construction of retail shops, storage facilities, parking garages, subways, tunnels and other structures enable the efficient use of below ground space. For these structures, an effective waterproofing solution is mandatory. High quality sheet lead serves as an impermeable moisture barrier against groundwater infiltration, a major factor impacting building longevity.



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What Are Lead Alloys And Its Applications/Uses?


GRAVITA

Lead Base Alloys
Lead Alloys
Because lead is very soft and ductile, it is normally used Commercially as lead alloys. Antimony, tin, arsenic, and calcium are the most common alloying elements. Antimony generally is used to give greater hardness and strength, as in storage battery grids, sheet, pipe, and castings. Antimony contents of lead-antimony alloys can range from 0.5 to 25%, but they are usually 2 to 5%.
Lead-calcium alloys have replaced lead-antimony alloys in a number of applications, in particular, storage battery grids and casting applications. These alloys contain 0.03 to 0.15% Ca. More recently, aluminum has been added to calcium-lead and calcium-tin-lead alloys as a stabilizer for calcium. Adding tin to lead or lead alloys increases hardness and strength, but lead-tin alloys are more commonly used for their good melting, casting, and wetting properties, as in type metals and solders. Tin gives the alloy the ability to wet and bond with metals such as steel and copper; unalloyed lead has poor wetting characteristics. Tin combined with lead and bismuth or cadmium forms the principal ingredient of many low-melting alloys.
Arsenical lead (UNS L50310) is used for cable sheathing. Arsenic is often used to harden lead-antimony alloys and is essential to the production of round dropped shot.

Applications

The most significant applications of lead and lead alloys are lead-acid storage batteries (in the grid plates, posts, and connector straps), ammunition, cable sheathing, and building construction materials (such as sheet, pipe, solder, and wool for caulking). Other important applications include counterweights, battery clamps and other cast products such as: bearings, ballast, gaskets, type metal, terneplate, and foil. Lead in various forms and combinations is finding increased application as a material for controlling sound and mechanical vibrations. Also, in many forms it is important as shielding against x-rays and, in the nuclear industry, gamma rays. In addition, lead is used as an alloying element in steel and in copper alloys to improve machinability and other characteristics, and it is used in fusible (low-melting) alloys for fire sprinkler systems.

Battery Grids. The largest use of lead is in the manufacture of lead-acid storage batteries. These batteries consist of a series of grid plates made from either cast or wrought calcium lead or antimonial lead that is pasted with a mixture of lead oxides and immersed in sulfuric acid.

Battery Grids

Type metals, a class of metals used in the printing industry, generally consist of lead-antimony and tin alloys. Small amounts of copper are added to increase hardness for some applications.

Cable Sheathing. Lead sheathing extruded around electrical power and communication cables gives the most durable protection against moisture and corrosion damage, and provides mechanical protection of the insulation. Chemical lead, 1% antimonial lead, and arsenical lead are most commonly employed for this purpose.

Lead Cable Sheath

Sheet. Lead sheet is a construction material of major importance in chemical and related industries because lead resists attack by a wide range of chemicals. Lead sheet is also used in building construction for roofing and flashing, shower pans, flooring, x-ray and gamma-ray protection, and vibration damping and soundproofing. Sheet for use in chemical industries and building construction is made from either pure lead or 6% antimonial lead. Calcium-lead and calcium-lead-tin alloys are also suitable for many of these applications.

Lead Sheet

Pipe. Seamless pipe made from lead and lead alloys is readily fabricated by extrusion. Because of its corrosion resistance and flexibility, lead pipes finds many uses in the chemical industry and in plumbing and water distribution system. Pipe for these applications is made from either chemical lead or 6% antimonial lead.

Lead Pipe

Solders in the tin-lead system are the most widely used of all joining materials. The low melting range of tin-lead solders makes them ideal for joining most metals by convenient heating methods with little or no damage to heat-sensitive parts. Tin-lead solder alloys can be obtained with melting temperatures as low as 182 °C and as high as 315 °C. Except for the pure metals and the eutectic solder with 63% Sn and 37% Pb, all tin-lead solder alloys melt within a temperature range that varies according to the alloy composition.

Solders

Lead-base bearing alloys, which are called lead-base babbitt metals, vary widely in composition but can be categorized into two groups:

  •      Alloys of lead, tin, antimony, and, in many instances, arsenic
  •      Alloys of lead, calcium, tin, and one or more of the alkaline earth metals
Lead-Base Bearing Alloys
Ammunition. Large quantities of lead are used in ammunition for both military and sporting purposes. Alloys used for shot contain up to 8% Sb and 2% As; those used for bullet cores contain up to 2% Sb.

Ammunition

Terne Coatings. Long terne steel sheet is carbon steel sheet that has been continuously coated by various hot dip processes with terne metal (lead with 3 to 15% Sn). Its excellent solderability and special corrosion resistance make the product well-suited for this application.

Trene Coating

Lead foil, generally known as composition metal foil, is usually made by rolling a sandwich of lead between two sheets of tin, producing a tight union of the metals.

Lead Foil

Fusible Alloys. Lead alloyed with tin, bismuth, cadmium, indium, or other elements, either alone or in combination, forms alloys with particularly low melting points. Some of these alloys, which melt at temperatures even lower than the boiling point of water, are referred to as fusible alloys.

Fusible Alloys

Anodes made of lead alloys are used in the electrowinning and plating of metals such as manganese, copper, nickel, and zinc. Rolled lead-calcium-tin and lead-silver alloys are the preferred anode materials in these applications, because of their high resistance to corrosion in the sulfuric acid used in electrolytic solutions. Lead anodes also have high resistance to corrosion by seawater, making them economical to use in systems for the cathodic protection of ships and offshore rigs.

Anodes

Below is listed the Unified Numbering System (UNS) designations for various pure lead grades and lead-base alloys.
Pure leads L50000 - L50099
Lead - silver alloys L50100 - L50199
Lead - arsenic alloys L50300 - L50399
Lead - barium alloys L50500 - L50599
Lead - calcium alloys L50700 - L50899
Lead - cadmium alloys L50900 - L50999
Lead - copper alloys L51100 - L51199
Lead - indium alloys L51500 - L51599
Lead - lithium alloys L51700 - L51799
Lead - antimony alloys L52500 - L53799
Lead - tin alloys L54000 - L55099
Lead - strontium alloys L55200 - L55299


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