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Friday, 14 February 2014

10 major nitrogen industrial applications | nitrogen industrial production methods

Nitrogen is a chemical element and it can be represented as N and atomic number of 7. In normal conditions nitrogen is a colorless, odorless and tasteless gas. Nitrogen makes up around 78 per cent in our surrounding atmosphere. Nitrogen is one of the primary nutrients critical for the survival of all living organisms. Although nitrogen is very abundant in the atmosphere, it is largely inaccessible in elemental form to most organisms.

Nitrogen is also present in other forms. When people think of nitrogen, they immediately associate it with the air in the environment. Nitrogen not only part of atmosphere but also part of the food they eat every day. Since its discovery, scientists have learned a lot about it and today with technology development nitrogen is commercially available in large amounts, various forms. The most common types are nitrous oxide and super coolant liquid nitrogen. Nitrous oxide is one of the nitrogen compound commonly known as laughing gas.

Liquid nitrogen is nitrogen in a liquid state at an extremely low temperature. It is produced industrially by fractional distillation of liquid air. Liquid nitrogen is a colorless clear liquid. Liquid nitrogen is a compact and readily transported source of nitrogen gas without pressurization. Liquid nitrogen has also become popular in the preparation of cocktails because it can be used to quickly chill glasses or freeze ingredients.

Liquid nitrogen can be applied for freezing and transport of food products, cryopreservation of biological samples, and coolant for superconductors, vacuum pumps, also used in cryotherapy to remove skin abnormalities, shielding materials from oxygen exposure, cooling materials for easier machining or fracturing.

This element is the lightest in the nitrogen group. Nitrogen can join up with other elements. The bonds are very effective because nitrogen’s outermost electron shell has few electrons. That is the reason why it is sometimes used as a buffer gas. Nitrogen is present as one of the building blocks or constituent of amino acids, proteins, nucleic acids, chlorophyll and other biomolecules.

Nitrogen is one of the primary nutrients critical for the survival of all living organisms. Although nitrogen is very abundant in the atmosphere as dinitrogen gas (N2), it is largely inaccessible in this form to most organisms, making nitrogen a scarce resource and often limiting primary productivity in many ecosystems. Only when nitrogen is converted from dinitrogen gas into ammonia (NH3) does it become available to primary producers, such as plants.

Nitrogen is a fascinating element with many unique properties and uses related to fertilizer, dynamite, medical anesthetic and even car racing. Read interesting facts about the nitrogen atom, liquid nitrogen, nitrous oxide, nitric acid, nitroglycerin and much more.

Nitrogen is present in all living things, including the human body and plants. Nitrogen gas is used in food storage to keep packaged or bulk foods fresh. It is also used in the making of electronic parts, for industrial purposes and has many other useful applications. Nitrogen gas is often used as an alternative to carbon dioxide for storing beer in pressurized kegs.

Titan, the largest moon of Saturn, has an atmosphere nearly entirely made of nitrogen. It is the only moon in our solar system known to have a dense atmosphere. Nitrogen is in a liquid state when at a very low temperature. Liquid nitrogen boils at 77 kelvin (−196 °C, −321 °F). It is easily transported and has many useful applications including storing items at cold temperatures, in the field of cryogenics, as a computer coolant, removing warts and much more.

Nitrogen role in health care and diseases

Decompression sickness involves nitrogen bubbles forming in the bloodstream and other important areas of the body when people depressurize too quickly from scuba diving. Similar situations can occur for astronauts and those working in unpressurized aircraft. Nitrous oxide (N2O) is used in hospitals and dental clinics as an anesthetic. Nitrous oxideis also used in motor racing to increase the power of engine and speed of the vehicle. Nitrous oxide is a considerable greenhouse gas and air pollutant. By weight is has nearly 300 times more impact than carbon dioxide.

Nitroglycerin is a liquid used to create explosives such as dynamite. It is often used in the demolition and construction industries as well as by the military. Nitric acid (HNO3) is a strong acid often used in the production of fertilizers. Ammonia (NH3) is another nitrogen compound commonly used in fertilizers.

Rainfall adds about 10 pounds of nitrogen to the soil per acre per year. The nitrogen oxides and ammonium that are washed to earth are formed during electrical storms, by internal combustion engines and through oxidation by sunlight. Some scientists also believe that some of the gaseous products that result from the transformation of nitrogen fertilizers may cause a depletion of the ozone (O3) layer around the earth. The extent of this possible damage has not been substantiated.

Crop residues decompose in the soil to form soil organic matter. This organic matter contains about 5 percent nitrogen. An acre-foot of soil having 2 percent organic matter would contain about 3,500 pounds of nitrogen. Generally, about 1 to 3 percent of this organic nitrogen is converted per year by microorganisms to a form of nitrogen that plants can use.

Commercial fertilizer nitrogen comes in three basic forms

  • Gaseous nitrogen
  • Liquid nitrogen
  • Dry nitrogen

All forms are equally effective when properly applied. Once applied, fertilizer nitrogen is subject to the same transformations as other sources of nitrogen.

Nitrogen Transformations

Nitrogen exists in a number of chemical forms and undergoes chemical and biological reactions.

Organic nitrogen to ammonium nitrogen

Organic nitrogen comprises over 95 percent of the nitrogen found in soil. This form of nitrogen cannot be used by plants but is gradually transformed by soil microorganisms to ammonium (NH4+). Ammonium is not leached to a great extent. Since NH4+ is a positively charged ion, it is attracted to and held by the negatively charged soil clay. Ammonium is available to plants.

Ammonium nitrogen to nitrate nitrogen (nitrification)

In warm, well-drained soil, ammonium transforms rapidly to nitrate (NO3-). Nitrate is the principle form of nitrogen used by plants. It leaches easily, since it is a negatively charged ion (anion) and is not attracted to soil clay. The nitrate form of nitrogen is a major concern in pollution.

Nitrate or ammonium nitrogen to organic nitrogen (immobilization)

Soil microorganisms use nitrate and ammonium nitrogen when decomposing plant residues. The addition of 20 to 70 pounds of nitrogen per ton of these residues is needed to prevent this transformation. After the residues are decomposed, the microbial population begins to die back and processes 1 and 2 take place.

Nitrate nitrogen to gaseous nitrogen (denitrification)

When soil does not have sufficient air, microorganisms use the oxygen from NO3- in place of that in the air and rapidly convert NO3- to nitrogen oxide and nitrogen gases (N2). These gases escape to the atmosphere and are not available to plants. This transformation can occur within two or three days in poorly aerated soil and can result in large loses of nitrate-type fertilizers.

Ammonium nitrogen to ammonia gas (ammonia volatilization)

Soils that have a high pH can lose large amounts of NH4+ by conversion to NH3 gas. To minimize these losses, incorporate solid ammonium-type fertilizers, urea and anhydrous ammonia below the surface of a moist soil.

Applications of nitrogen

This element is present in virtually all pharmacological drugs. In the form of nitrous oxide it is used as an anesthetic. Cryopreservation also uses the gas to conserve egg, blood, sperm and other biological specimens. The CPUs in computers use the gas to keep them from heating up. X-ray detectors also rely on this element.

The element is used in controlling pollution. It is effective in getting rid of unstable organic compounds in liquids. Many industries use it to destroy toxic liquids and vapors in industrial tools. As nitrogen dioxide, the element is vital in the industrial sector. It also serves as an oxidation reaction catalyst. Apart from being an oxidizing agent, it can also be used as a flour bleaching agent and rocket fuel.

It has found several uses in the industrial sector, of which a few important uses are explained below.

Light Bulbs

Nitrogen is often used in making light bulbs. It serves as an inexpensive substitute for argon in incandescent light bulbs.

Packaged Foods

Nitrogen is used to preserve the freshness of packaged foods. Nitrogen can prevent the oxidation of food, and thus delay rancidity and other forms of oxidative damage.

Fertilizers

Nitrogen is one of the most important ingredients in fertilizers, to increase soil fertility. It is used to make other fertilizers like ammonia and urea, which are used to promote plant growth and increase yield.

Reactive compounds production

 It can produce a range of unstable and highly reactive compounds, like nitrogen triiodide,ammonium nitratetrinitrotoluene (TNT), nitric acid, and nitroglycerin.

Electronic Parts

Nitrogen is used for making transistors, integrated circuits, and diodes.

Stainless Steel

Nitrogen is often used in manufacturing stainless steel, electroplating processes in order to make it stronger and more resistant to corrosion.

High Voltage Equipment

Dried and pressurized nitrogen gas is used as a dielectric gas for high voltage equipment. Nitrogen is also used as a pressurizing gas to propel liquids through pipelines.

Nitrogen is also used for pollution control, especially for eliminating volatile organic compounds from liquids. It can help remove harmful vapors and liquids from industrial equipment as well.

Pharmaceuticals

Nitrogen is a constituent of almost every major class of drugs, including antibiotics. In the form of nitrous oxide, nitrogen is used as a pharmaceutical anesthetic agent.

Oxygen history, evolution, production, industrial uses steel production, rocket propellants, medicine

Oxygen is a tasteless gas. Oxygen has no smell or color. It comprises 22 per cent of the air. Oxygen is found in the human body, the Sun, oceans and the atmosphere. Oxygen is part of the air people use to breathe. Human exposure to atmospheres containing 12 per cent or less oxygen will bring about unconsciousness without warning. It is also part of the stellar life cycle.

Oxygen is shipped as a non liquefied gas at pressures of 2000 psig (138 bar) or above, also as a cryogenic liquid at pressures and temperatures below 200 psig (13.8 bar) and -2320F (-146.50C). Oxygen is produced at air separation plants by liquefaction of atmospheric air and separation of the oxygen by fractionation. Very small quantities are produced by the electrolysis of water.

Oxygen also acts as a ligand for transition metals, forming metal-O2 bonds with the iridium atom in Vaska's complex, with the platinum in PtF6. Oxygen combines with iron and present at center of the heme group of hemoglobin

About one-half of the earth's crust is made up of chemical compounds containing oxygen, and a fifth of our atmosphere is occupied by oxygen gas. The human body is about two-thirds oxygen. Although oxygen has been present since the beginning of scientific investigation, it wasn't discovered and recognized as a separate element until 1774 when Joseph Priestley of England. Joseph Priestley isolated oxygen by heating mercuric oxide in an inverted test tube with the focused rays of the sun.

Oxides are generated when oxygen joins with other elements. It is part of hydroxides and various acids. Oxygen can be cooled under boiling point. It will turn light blue. This color is retained even when in a solid state.

In 1895, Karl Paul Gottfried von Linde of Germany and William Hampson of England independently developed a process for lowering the temperature of air until it liquefied. By carefully distillation of the liquid air, the various component gases could be boiled off one at a time and captured. This process quickly became the principal source of high quality oxygen, nitrogen, and argon.

The first use of liquid rocket propellants came in 1923 when Robert Goddard of the United States developed a rocket engine using gasoline as the fuel and liquid oxygen as the oxidizer. In 1926, he successfully flew a small liquid-fueled rocket a distance of 184 ft (56 m) at a speed of about 60 mph (97 kph).

After World War II, new technologies brought significant improvements to the air separation process used to produce oxygen. Production volumes and purity levels increased while costs decreased. In 1991, over 470 billion cubic feet (13.4 billion cubic meters) of oxygen were produced in the United States, making it the second-largest-volume industrial gas in use.

Worldwide the five largest oxygen-producing areas are Western Europe, Russia (formerly the USSR), the United States, Eastern Europe, and Japan.

French scientist Antoine Lavoisier, with the basics of Joseph Priestley experiments, experimented further and determined that it was one of the two main components of air. Lavoisier coined the term to new gas as oxygen using the Greek words oxys, meaning sour or acid, and genes, refers to producing or forming.

Approximately 100 million tons of O2 is extracted from the air annually for industrial purposes. The steel industry is the major consumer of oxygen for its major process. In steel industry the process of smelting iron ore into steel requires high pressure injection of oxygen into the molten steel to remove impurities from the steel. In the steelmaking industry huge quantities of O2 are blown through the impure molten ore, where it burns off any impurities that are present (particularly carbon). About 1 tone of O2 is required for every tone of finished steel.

Oxygen is required to produce energy in industrial processes, generators and ships. It is also used in airplanes and cars. As liquid oxygen, it burns spacecraft fuel. This produces the thrust needed in space.

Astronauts’ spacesuits have close to pure oxygen. Oxygen is needed by all living organisms. Through a process known as aerobic respiration, energy from food is generated. This allows humans and animals to perform their daily activities.

Oxygen comprises a fifth of air volume, two-thirds of the human body and 87 per cent water. In its natural form it is all over the atmosphere. Commercial preparation involves fractional distillation of air and liquefaction and water electrolysis. Oxygen can be used to make compounds with all elements minus inert gasses. Oxygen may be dissolved.

In 1901, compressed oxygen gas was burned with acetylene gas in the first demonstration of oxy-acetylene welding. This technique became a common industrial method of welding and cutting metals.

Raw Materials

Oxygen can be produced from a number of materials, using several different methods. The most common natural method is photo-synthesis, in which plants use sunlight convert carbon dioxide in the air into oxygen. This offsets the respiration process, in which animals convert oxygen in the air back into carbon dioxide.

The most common commercial method for producing oxygen is the separation of air using either a cryogenic distillation process or a vacuum swing adsorption process. Nitrogen and argon are also produced by separating them from air.

Oxygen can also be produced as the result of a chemical reaction in which oxygen is freed from a chemical compound and becomes a gas. This method is used to generate limited quantities of oxygen for life support on submarines, aircraft, and spacecraft.

Hydrogen and oxygen can be generated by passing an electric current through water and collecting the two gases as they bubble off. Hydrogen forms at the negative terminal and oxygen at the positive terminal. This method is called electrolysis and produces very pure hydrogen and oxygen. It uses a large amount of electrical energy, however, and is not economical for large-volume production.

Most commercial oxygen is produced using a variation of the cryogenic distillation process originally developed in 1895. This process produces oxygen that is 99+% pure. More recently, the more energy-efficient vacuum swing adsorption process has been used for a limited number of applications that do not require oxygen with more than 90-93 per cent purity.

Here are the steps used to produce commercial-grade oxygen from air using the cryogenic distillation process.

Oxygen Toxicity

This condition takes place when someone breathes excessive pure oxygen. The gas is essential for living, but only up to a point. Humans can only breathe 21 percent oxygen. The other elements are composed of nitrogen and other elements. When too much oxygen is inhaled, humans will experience difficulty breathing. Other symptoms will manifest. These include inflammation of the airways, nausea and tunnel vision.

Toxicity can be due to elevated oxygen levels or other causes. High pressure, short duration exposure can lead to central nervous system damage. Long term exposure may cause ocular or pulmonary problems. Central nervous system oxygen toxicity is usually experienced by divers. Those who spend time at high altitudes are also susceptible. Toxicity can occur when a diver goes in deep enough. This is because the diver takes in more oxygen than usual.

Symptoms include twitching, dizziness and nausea. In extreme cases, seizures or death occur. However, toxicity can take place if oxygen is higher than 21 per cent in normal atmospheric pressure and at 50 per cent, toxicity will occur.

Materials of Construction

Gaseous oxygen is noncorrosive and may be contained in systems constructed of any common metal. Stainless steel, bronze and brass are the preferred material for all metal components coming in contact with oxygen. At the temperatures of liquid oxygen, ordinary carbon steels and most alloy steels lose their ductility and are therefore considered unsatisfactory for liquid oxygen service. Carbon Steel cannot be adequately cleaned for oxygen service.

In healthcare institutions like hospitals, oxygen supplies are kept in stock. These are provided to patients who have difficulty breathing. This breathing apparatus is also used by astronauts walking in space, scuba divers and mountaineers. Oxygen gas is used to destroy bacteria. The same oxygen gas is used to treat victims of carbon monoxide poisoning.

Oxygen gas is used in water treatment and chemical combustion. Scientific researchers use the oxygen-18 and oxygen-16 isotopes in fossils to determine Earth’s climate millennia ago. This gas is also used in polyester polymers and antifreeze production. These polymers are used to create fabrics and plastics. You will also find oxygen tanks in aircraft and submerge vessels.

Oxygen is essential for life and it takes part in processes of combustion, its biological functions in respiration make it important.

Oxygen is sparingly soluble in water, but the small quantity of dissolved oxygen in is essential to the life of fish.

Oxygen Uses

The uses of oxygen are varied. Oxygen is used in puland paper manufacturing, ceramic creation, glass making and petroleum processing. It is also part of pharmaceuticals, metal refining and other elements.

Oxygen is used extensively in medicine, high altitude flying, deep-sea diving and a power source in the space programs. Industrial applications include utilization with acetylene, propane, hydrogen and other fuel gases for such purposes as metal cutting, welding, hardening and scarfing.

One of its major uses is in production of synthesis gas which is used to make gasoline, methanol and ammonia. It is also used in production of nitric acid, ethylene and other compounds.

Oxygen gas is used with hydrogen or coal gas in blowpipes and with acetylene in the oxy-acetylene torch for welding and cutting metals.

Oxygen gas is also used in a number of industrial processes.

Medicinally, oxygen gas is used in the treatment of pneumonia and gas poisoning, and it is used as an anesthetic when mixed with nitrous oxide, ether vapour, etc.

Carbon Dioxide is often mixed with the oxygen as this stimulates breathing, and this mixture is also used in cases of poisoning and collapse for restoring respiration.

Liquid oxygen mixed with powdered charcoal has been used as an explosive.

Oxygen is important for all combustion process, such as the burning of the hydrocarbon fuels such as oil, coal, petrol, natural gas which heat our homes and power our cars.

Fires need O2 to burn, and removal of O2, by for example smothering or spraying with CO2, is one way to extinguish fires.

Welding, using oxy-acetylene torches is another important industrial application, whereby acetylene gas (the fuel) and oxygen are mixed in the correct proportions and ignited to provide an intensely hot flame.

Sodium carbonate, soda ash, washing soda production using solvay process

What is soda ash?

What is washing soda?

What is the chemical name of soda ash and washing soda?

Sodium carbonate is the chemical name for soda ash and washing soda. Major source of soda ash is trona ore. Sodium carbonate occurs naturally in arid regions. It is found in the form of deposits on locations where lakes evaporate. Sodium carbonate is one of the most basic industrial chemicals. It is found in large natural deposits and is mined in Wyoming.

Deposits of sodium carbonate are found in large quantities in different regions of the world but major locations include United States, China, Botswana, Uganda, Kenya, Mexico, Peru, India, Egypt, South Africa and Turkey. It is found both as extensive beds of sodium minerals and as sodium-rich waters (brines).

The principal applications of sodium carbonate are in the manufacture of glass and the production of chemicals. It is also used in processing wood pulp to make paper, in making soaps and detergents, in refining aluminum, in water softening, and in many other applications.

It can help remove alcohol and grease stains from clothing, as well as calcifications in everything from coffee pots and espresso makers to boilers and hot water heaters.

Soda ash can also be used to increase the alkalinity in swimming pools, helping to ensure the proper pH balance of the water. It can be used in dying to help the dye bond to the fabric effectively. Photographers also use a sodium carbonate solution as part of thephoto development process.

Washing soda has significant economic importance because of its applications in manufacturing glass, chemicals, paper, detergents and many other products. It has been used since ancient times.

Sodium carbonate is having characteristics like white, anhydrous, powdered or granular material. Soda ash is an alkali that has a high ph in concentrated solutions. It can irritate the eyes, respiratory tract and skin. It should not be ingested. Soda ash is made in three important grades – light grade, intermediate grade, and dense grade.

Anhydrous sodium carbonate loses weight when heated

Na2CO3(solid) → Na2O (solid) + CO2 (gas)

Sodium carbonate although readily soluble in water and it reaches maximum solubility at the relatively low temperature of 35.4oC.

How to transport soda ash?

Light and dense soda ash is normally packaged in plastic or polyethylene lined bags, multiwall paper bags. Covered hopper cars with bottom discharge are the most common rail cars used for bulk soda ash.

Sodium carbonate is a fragile, crystalline product subject to breakage from conveying equipment. Soda ash generates micron-sized particles that require high-efficiency collectors.

Soda ash is usually stored in warehouse for a short time. It can be stored in bulk as a pile on the floor and reclaimed by a front-end loader or other bulk-handling machine.

Soda ash production

The Leblanc process, the first successful commercial process for making soda, is no longer used in the United States but played a major role in the Industrial Revolution. 

Soda ash can be made synthetically using limestone, salt and ammonia. This is known as the Solvay process, and was the main source of soda ash until the Wyoming trona deposits were discovered. However, it is more expensive than mining natural sodium carbonate deposits.

A series of refining steps are required to produce soda ash from trona ore. First the raw ore from the mine is crushed and screened. The material is then fed to rotary calciners and heated. In this process, the trona decomposes to form crude soda ash, which is dissolved in water.

The insoluble shales are separated from the solution by a combination of settling and filtration steps and the resulting insoluble tailings are taken back into the mine as backfill. The soda ash solution is treated to remove organic materials yielding a high-purity saturated solution of sodium carbonate.

Next, the solution is fed to crystallizers where water is evaporated and sodium carbonate monohydrate crystals are formed. The industry-familiar term "mono-process" originates from this process step. The crystals are dewatered and washed using cyclones and centrifuges, and the solution is recycled to the evaporator units for further recovery of soda ash. The monohydrate crystals are fed to rotary kilns where they are dried to finished soda ash. Finally, product is screened and sent to storage silos awaiting rail and truck load out.

Soda ash also is used to clean the air and soften water. As environmental concerns grow, demand increases for soda ash used in the removal of sulfur dioxide and hydrochloric acid from stack gases.

Chemical manufacturers use soda ash as an intermediate to manufacture products that sweeten soft drinks (corn sweeteners), relieve physical discomfort (sodium bicarbonate) and improve foods and toiletries (phosphates). Household detergents and paper products are a few other common examples of readily identifiable products using soda ash.

Light soda ash is one of the most important basic industrial chemicals. Light soda ash is used to regulate pH in many chemical process streams. The superior buffering capacity of soda ash versus caustic soda offers advantages in adjusting plant wastewater pH ranges.

Applications

Soda ash is used as the sodium source for sodium sulfite/bi-sulfite pulping liquors used in the sulfite, CMP, and CTMP processes, and in NSSC pulping.

It is also possible to replace a portion of the caustic soda with sodium carbonate in many pulp bleaching applications such as caustic extraction or hydrogen peroxide bleaching of mechanical or chemical pulps.

It is also possible to replace a portion of the caustic soda in many pulp bleaching applications such as caustic extraction or hydrogen peroxide bleaching of mechanical or chemical pulps.

In addition, washing soda is the most widely used fixed alkali for the manufacture of other alkali products, sodium salts, glass, soap, sodium silicates, detergent, bicarbonates, bichromates, cellulose and rayon, iron and steel, aluminum, cleaning compounds, textiles and dyestuffs, drugs and many other materials. It is also used as an alkali for household purposes and as washing powder by laundries.

One of the most common products that can be made with soda ash is glass. More than 50 per cent of all sodium carbonate produced around the world is used for this purpose. When mixed in proportion with sand and calcium carbonate, heated to the right temperature, and then cooled quickly, the end result is soda-lime silica glass with excellent durability and clarity.

Soda ash is a very common industrial chemical as well. In addition to food and cosmetic products, it’s also finds major applications in agricultural sector chemicals such as fertilizers. When it comes to exhaust towers and chemical stacks, this ash can play a very important role in air purification because when sodium carbonate reacts with sulfur dioxide and hydrochloric acid, for example, less harmful compounds are produced.

In laboratories, this sodium salt serves as an excellent electrolyte in the electrolysis process. It helps to reduce the water content in the clay and makes the task of molding the clay in the shape of a brick easier. In the dyeing industry, it is used to improve the chemical bonding between the dye and the fiber.

Washing soda is a key component of laundry soaps and other household cleaning products as it can easily remove dirt and tough greasy stains from clothes, utensils, floors, and various other surfaces. It is also used as a cleansing agent for removing dirt stuck on silver and glass items. Water in the swimming pools turns acidic due to repeated addition of chlorine as a disinfectant. Washing soda is added to this water to make it chemically neutral.

Sodium carbonate is important in taxidermy for preparing hunting trophies. When added to boiling water, it helps in the removal of flesh from the skulls and bones of dead animals. Washing soda acts as a strong base and can neutralize acidic effects.

Manufacturing of sodium carbonate by solvay process

Sodium carbonate (Na2CO3) is found naturally or is manufactured from natural salt i.e., sodium chloride (common salt). It has many uses but, one of the major notable applications is in making of glass. Soda ash is a key chemical for producing soap, paper making, baking soda production, and bleaching fabrics and paper.

Origin of soda ash term

The name "soda ash" is based on the principal historical method of obtaining alkali, which was by using water to extract it from ashes. The word "soda" (from the Middle Latin) originally referred to certain plants that grow in salt marshes; it was discovered that the ashes of these plants yielded the useful alkali "soda ash."

Why sodium carbonate called as washing soda?

CO32- from dissolved Na2CO3 can precipitate Mg2+ and Ca2+ ions from hard water as the insoluble carbonates, preventing them from forming a precipitate with soap resulting in scum. For this reason, sodium carbonate is also known as washing soda.

Soda ash is used to produce the NaHSO3 necessary for the sulfite method of separating lignin from cellulose.

Sodium carbonate removes grease from wool and neutralizes acidic solutions.

Na2CO3 is used to remove SO2(g) from flue gases in power stations.

Na2CO3 was produced by two processes

  • Leblanc process
  • Ernest Solvay process

The Solvay Process (also known as the ammonia-soda process), developed in 1861, is the world's major industrial process for the production of sodium carbonate (NaCO3), or soda ash.

Solvay process history

In 1861, after realizing the polluting impacts of the Leblanc Process, Belgian industrial chemist Ernest Solvay rediscovered and perfected Augustin Fresnel's reaction. This process recovered the ammonia in the reaction for re-use, therefore making it less detrimental to the environment.

In 1874, other companies had bought the right to use the Solvay process in their own plants. Now the sodium carbonate production market became a booming industry with several plants opening worldwide.

In 1890's, Solvay-based process plants produced the majority of the world's soda ash.

The materials needed in the Solvay process are nearly all readily available and inexpensive:

Solvay process feedstocks

Salt Brine – Salt brine as one of the feedstock provides salt and water and it can be easily sourced from both inland and the ocean.
Limestone

Manufacturing steps in solvay process


















The following steps are involved in solvay process and in this process some amount of ammonia recycled back as feedstock to start new round of solvay process.

  • Brine purification
  • Ammoniation of brine
  • Reactions in Solvay Tower
  • Reactions in klin / Separation of solid sodium hydrocarbonate
  • Formation of sodium carbonate
  • Ammonia Recovery

Brine purification

Brine or brine solution is a solution of salt and water. It is mainly used as a preservative for vegetables, fish, fruit, and meat through a process known as brining. The high salt content in Brine prevents the growth of bacteria and thus helps to preserve the food for a long time without creating any difference in taste. Brine is widely used all over the world for various food preparations and is best suited for delicacies made from meat and fish.

Brine is both naturally found and artificially produced as well. Brine has many commercial applications. Brine is be prepared by dissolving rock salt post hydraulic fracturing of a well. The process of creating Brine is more than simple mixing. It is done by an electronically controlled and monitored process. Huge quantities of Brine are extracted by installing a self-contained hydraulic system from heavy salt concentrations areas.

Applications of brine

  • Brine is an extremely useful substance used in domestic chores as well as commercial applications.
  • Brine is used for the production of salts. The brine is generally evaporated and then processed to get the common salt or table salt (Nacl).
  • Brine is widely used for food preservation.The brine can be mixed with a wide variety of herbs and spices for flavor.
  • Brine is often used for marinating meat. It makes the flesh juicier, and tender. Apart for that, Brine kills the microorganisms that harbor in meat. The process of marinating the meat with brine, prior to cooking reduces the cooking time.
  • Brine solution is an excellent prewetting agent and commercially used to treat the roads. The solution is non-corrosive, biodegradable, and environmentally friendly.
  • Brine is used to transfer heat from one place to another place and is largely used for refrigeration.
  • Brine has a lower freezing point than water and can be cooled to below zero Celsius. Hence it is effectively used as coolant other than plain water. Brine freezes at -21ºC (-6ºF). It is used for cooling steels and other metals.
  • Brine is often used for Pickling.
  • Brine is an important source of chlorides, sulphates of magnesium and potassium apart from natural salt. These salts are extracted through electrolysis.
  • Brine solution cures Psoriasis, Osteoporosis, Arthritis, Gout and Herpes sores.
  • Brine steam inhalation cures asthma, bronchitis, acute and chronic sinus and ear infections.
  • Brushing teeth with concentrated Brine solution helps to protect tooth enamel.
  • Brine poultice is used to sterilize open wounds.
  • Brine baths improves circulatory system and control high temperature during viral fever.
  • Brine acts an excellent detoxification solution and improves the metabolism. It maintains the body’s pH Factor and eliminates heavy metals.

The solvay process will commences with brine purification which involves

Brine solution is concentrated by evaporation to at least 30 per cent

Calcium, magnesium and iron are collected as precipitants in this reaction

Ca2+(aq) + CO32-(aq) → CaCO3(s)
Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s)
Fe3+(aq) + 3OH-(aq) → Fe(OH)3(s)

Following the precipitation reaction brine solution is then filtered and passed through an ammonia tower to dissolve ammonia.

Through this process energy is released because of its exothermic nature, thereby, the ammonia tower will get cooled by this energy.

Ammoniation of brine

In the solvay process second step is the ammoniation of brine solution. Ammonia gas is absorbed in concentrated brine to give a solution containing both sodium chloride and ammonia.

Reactions in klin / Separation of solid sodium hydrocarbonate

Lime Kiln

A lime kiln is used to produce quicklime through the calcination of limestone. This reaction takes place at 900°C.

Types of kilns

  • Shaft kilns
  • Counter current shaft kilns
  • Regenerative kilns
  • Annular kilns
  • Rotary kilns

Kilns are fed with a limestone/coke mixture (13:1 by mass).  The coke burns in a counter-current of pre-heated air

C(s) + O2(g) → CO2(g)

The heat of combustion raises the temperature of the kiln and the limestone decomposes

CaCO3(s)  CaO(s) + CO2(g)

The gas, containing approximately 40 per cent carbon dioxide, is freed of lime dust and sent to the carbonating (Solvay) towers.  The residue, calcium oxide, is used in ammonia recovery.

Reactions in solvay tower

The Solvay Tower is tall and contains a set of mushroom-shaped baffles to slow down and break up the liquid flow so that the carbon dioxide can be efficiently absorbed by the solution.  Carbon dioxide, on dissolving, reacts with the dissolved ammonia to form ammonium hydrogen carbonate

NH3(aq) +  H2O(l) + CO2(g) → NaHCO3(s)

The solution now contains ions Na+(aq), Cl-(aq), NH4+(aq) and HCO3-(aq).  Of the four substances which could be formed by different combinations of these ions, sodium hydrogencarbonate (NaHCO3) is the least soluble. It precipitates as a solid in the lower part of the tower, which is cooled.

NaCl(aq) + NH3(aq) +H2O(I) +CO2(g) → NaHCO3(s) + NaCl (aq)

Formation of sodium carbonate

Suspended sodium hydrogen carbonate is removed from the carbonating tower and heated at 300oC to produce sodium carbonate:

2NaHCO3(s) → Na2CO3(s) + H2O (g) + CO2 (g)

Ammonia Recovery

CaO is formed as a by-product of the thermal decomposition of limestone in the lime kiln.

This CaO enters a lime slaker to react with water to form calcium hydroxide:

CaO(s) + H2O (l) → Ca(OH)2(aq)

The calcium hydroxide produced here is reacted with the ammonium chloride separated out of the carbonating tower by filtration:

Ca (OH)2(aq) + 2NH4Cl(aq) → CaCl2(aq) + 2H2O(l) + 2NH3(g)

10 major chlorine industrial applications used in pharmaceutical,paper,textile industries

Chlorine is the most abundant member of the halogen family of periodic table elements. Chlorine is an important chemical in our day-to-day life. Chlorine is a clear amber-colored liquid about 1.5 times heavier than water. Gaseous chlorine is greenish-yellow, about 2.5 times as heavier than air, which will cause it to initially remain near the ground in areas with little air movement. Chlorine has a pungent odor. Chlorine is a powerful oxidizing agent and it must be handled carefully. Chlorine is a yellow-green gas at room temperature.

Chlorine is a major building block for the chemical and pharmaceutical industry. Chlorineis also known as disinfectant in drinking water and in swimming pools, chlorine contributes to advances in areas as diverse as disinfecting, medicine, public safety and enhancing our everyday life.

Chlorine is not flammable, but may react explosively or form explosive compounds with many common substances (including acetylene, ether, turpentine, ammonia, natural gas, hydrogen, and finely divided metals).

Chlorine is slightly water soluble, and reacts with moisture to form hypochlorous acid (HClO) and hydrochloric acid (HCl).

Chlorine is commonly pressurized and cooled for storage and shipment as an amber-colored liquid.

Chlorine gas is a harmful poison, which was the first gas used in chemical warfare in World War I. It causes suffocation, constriction of the chest, tightness in the throat, and edema of the lungs. As little as 2.5 mg per litre in the atmosphere causes death in minutes, but less than 0.0001 percent by volume may be tolerated for several hours.

Surprising sources of chlorine

A Chinese folk medicine plant contains five natural organo chlorine compounds.

An Ecuadorian tree frog produces a chlorinated alkaloid, with pain-killing properties several hundred times more powerful than morphine.

A natural organ chlorine antibiotic i.e., vancomycin, is a key defense against hospital Staphylococcus infections.

Some natural organ chlorinated products exhibit potent antibacterial and anticancer properties

NASA’s Curiosity Rover, currently exploring the surface of Mars, has detected the presence of chlorine on the Red Planet. A Mars expert at the University of Michigan in Ann Arbor, US, stated that "the presence of perchlorates implies a source of chlorine, which was most likely derived from briny water or volcanic activity in the past".

NASA also detected chlorinated methane compounds when soil samples were analyzed in Curiosity's on-board laboratory.

Chlorine constitutes about 0.013 percent of the Earth's crust.

Free chlorine has been reported as a very minor constituent of volcanic gases, of which hydrogen chloride (q.v.) is a fairly common component.

Chlorine, as the chloride ion Cl-, is the main negative ion in ocean water (1.9 percent by weight) and in inland seas such as the Caspian Sea, the Dead Sea, and the Great Salt Lake of Utah

It is found in evaporite minerals, for example, combined with sodium, as rock salt (halite) and in the minerals chlorapatite and sodalite.

Natural chlorine is a mixture of two stable isotopes: chlorine-35 (75.53 percent) and chlorine-37 (24.47 percent).

The Chloride ion is present in the body fluids of higher animals and as hydrochloric acid in the digestive secretions of the stomach.

Properties

Chlorine molecules are composed of two atoms (Cl2). Chlorine combines directly with almost all the elements to give chlorides

Besides the -1 oxidation state of the chlorides, chlorine also exhibits +1, +3, +5, +7 oxidation states, respectively, in the following ions: hypochlorite, ClO-; chlorite, ClO-2 ; chlorate, ClO-3 and perchlorate, ClO-4 .

Chlorine also exists in the forms of four oxides, such as chlorine monoxide (Cl2O),chlorine dioxide (ClO2), dichlorine hexoxide (Cl2O6), and dichlorine heptoxide (Cl2O7). All the four oxides are highly reactive and unstable, have been indirectly synthesized.

Chlorine can displace the heavier halogensbromine and iodine, from their ionic compounds and undergoes addition or substitution reactions with organic compounds. Chlorine enters directly or as an intermediate into the synthesis of many organic chemicals that are used as solvents, dyes, plastics, and synthetic rubber.

Many chemicals, plastics and medicines depend on chlorine during the manufacturing process, although the chemical is not contained in the end product.

Two third of all chlorine is used in the production of plastics, such as PVC, Poly-Urethanes, Epoxy-resins, Teflon, Neoprene etc., for use in construction, automotive, electronic and electrical industries.

85 per cent of medicines, including many lifesaving drugs, are made using chlorine chemistry.

25 per cent of medical devices contain chlorine, including blood bags, sterile tubing, heart catheters, prosthetics and X-ray films.

More than 90 per cent of Western Europe's drinking water is made safe with the help of chlorine. Worldwide waterborne diseases kill 15 million people each year.

Chlorine production methods

Most chlorine is industrially produced by the electrolysis of brine. Chlorine is also obtained as a by-product in the manufacture of sodium metal by the electrolysis of molten sodium chloride.

One of the laboratory methods to prepare chlorine is reaction between sulfuric acid andsodium hypochlorite or hydrochloric acid with sodium hypochlorite. Sulfuric acid or hydrochloric acid reacts with sodium hypochlorite solution to release chlorine gas but reacts with sodium chlorate to produce chlorine gas and chlorine dioxide gas.

Industrial production of chlorine is through by following process

  • The membrane cell process
  • The mercury cell process
  • The diaphragm cell process

Chlorine applications

Chlorine and its compounds are used extensively for bleaching in the paper and textile industries, for disinfecting municipal water supplies, for household bleaches and germicides, and for the production of many organic and inorganic chemicals, in the separation of such metals as copper, lead, zinc, nickel, and gold from their ores.

Chlorinated solvents are used as an extraction medium in pharmaceutical processes, in printing, mining and plastics processing, in the manufacture of adhesives and in paint & varnish remover

Chlorine compounds have been used in pharmaceutical formulations for many years and play a part in the eradication of infection and disease. It is not only used in antiseptics, but in drugs such as chloramphenicol.

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