Industrial processes

The Bayer process is the principal industrial means of producing alumina, itself important in the Hall-Héroult process for producing aluminum. Bauxite, the most important ore of aluminum, contains only 40-60% alumina, Al2O3, the rest being a mixture of silica, various iron oxides, and titanium dioxide. The alumina must be purifed before it can be refined to aluminum metal. In the Bayer process, bauxite is washed with a hot solution of sodium hydroxide, NaOH, at 250°C. This converts the alumina to alumini ...

Including:

• Bayer process - History

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A Ziegler-Natta catalyst is a catalyst used in the production of unbranched, stereoregular vinyl polymers. Ziegler-Natta catalysts are typically based on titanium tetrachloride and the organometallic compound triethylaluminium. These catalysts were discovered in the 1950s by Karl Ziegler, who used a mixture of the above compounds to catalyse the polymerisation of ethylene. Giulio Natta, using the same mixture to catalyse propylene, discovered that the process gave a stereoregular pol ...

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Vulcanization, or curing, of rubber, is a chemical process in which individual polymer molecules are linked to other polymer molecules by atomic bridges. The end result is that the springy rubber molecules become locked together to a greater or lesser extent. This makes the bulk material harder, much more durable and also more resistant to chemical attack. It also transforms the surface of the material from a sticky feel to a smooth soft surface which does not adhere to metal or plastic substrates. Vulcanization - ...

Including:

• Vulcanization - Reason for vulcanizing
• Vulcanization - Description
• Vulcanization - Overview and history
• Vulcanization - Goodyear's contribution
• Vulcanization - Subsequent developments

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In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e.g. kerogens or heavy hydrocarbons) are converted to simpler molecules (e.g. light hydrocarbons) by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of any catalysts. Cracking chemistry - Applications. In an oil refinery cracking processes allow the production of "light" products (such as LPG and gasoline) from ...

Including:

• Cracking chemistry - Applications
• Cracking chemistry - Fluid Catalytic Cracking
• Cracking chemistry - Hydrocracking
• Cracking chemistry - Steam Cracking
• Cracking chemistry - Chemistry
• Cracking chemistry - Catalytic Cracking
• Cracking chemistry - Thermal Cracking
• Cracking chemistry - History

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Alkylation is the transfer of an alkyl group from one molecule to another. In a standard oil refinery process, alkylation combines low-molecular-weight olefins (primarily a mixture of propylene and butylene) with isobutane in the presence of a catalyst, either sulfuric acid or hydrofluoric acid. The product is called alkylate and is composed of a mixture of high-octane, branched-chain paraffinic hydrocarbons. Alkylate is a premium gasoline blending stock because it has exceptional antiknock properties and is clean burning. The ...

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Austenite (γ-iron; hard) Bainite Martensite Cementite (iron carbide; Fe3C) Ferrite (α-iron; soft) Pearlite (88% ferrite, 12% cementite) Carbon steel (up to 2.1% carbon) Stainless steel (alloy with chromium) Tool steel (very hard; heat-treated) Cast iron (>2.1% carbon) Wrought iron (almost no carbon) Crucible steel describes a number of different techniques for making steel alloy by slowly heating and cooling iron and carb ...

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There are two main solvents used in EPD, water and organic liquids. Organic liquids are usually preferred to water based solutions as in water based solutions, the resulting hydrolysis of water due to the high potential difference causes gas formation within the suspension. The charge of the colloidal particle also plays a vital role in the electrophoretic mobility of the suspension, and this charge originates from ...

See also:

Electrophoretic deposition, Electrophoretic deposition - Process of electrophoretic deposition, Electrophoretic deposition - Factors affecting EPD, Electrophoretic deposition - Uses of EPD

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Chromic acid (CrO3): 250–300 g/l. Sulfuric acid: 2.5–3.0 g/l. Operating Temperature: 45–60 °C. Plating current: 1.55–3.10 kiloamperes per square meter DC. Maximum superimposed AC ripple allowed is 18%, preferred ripple is 5% to 10%. Anodes: lead with up to 7% tin or antimony. Chromium may be stripped anodically in an aqueous solution of sodium hydroxide. The materials described herein are extremely hazardous. They are toxic, corrosive and damaging to the environment. The ...

See also:

Chrome plating, Chrome plating - Chromium plating solutions, Chrome plating - Typical bath composition and operation of the hexavalent bath, Chrome plating - Quality requirements

Read more here: » Chrome plating: Encyclopedia II - Chrome plating - Typical bath composition and operation of the hexavalent bath

In an oil refinery cracking processes allow the production of "light" products (such as LPG and gasoline) from heavier crude oil distillation fractions (such as gas oils) and residues. Fluid Catalytic Cracking (FCC for short) produces a high yield of gasoline and LPG while hydrocracking is a major source of jet fuel, gasoline components and LPG. Thermal cracking is currently used to "upgrade" very heavy fractions ("upgrading", "visbreaking"), or to produce light fractions or distillates, burner fuel and/or petroleum coke ...

See also:

Cracking chemistry, Cracking chemistry - Applications, Cracking chemistry - Fluid Catalytic Cracking, Cracking chemistry - Hydrocracking, Cracking chemistry - Steam Cracking, Cracking chemistry - Chemistry, Cracking chemistry - Catalytic Cracking, Cracking chemistry - Thermal Cracking, Cracking chemistry - History

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Fourdrinier machine - Wet end. There are four main sections to the Fourdrinier; the first is typically known as the wet end. Pulp may be delivered to the Fourdrinier machine in a liquid slush (pulp - water mixure) directly from the pulping process. Alternatively, pulp may be supplied in dried sheets which are then broken down in water to produce a similar slush, before being fed to the wet end. In the wet end, pulp is combined with sizing, fillers, colours, and possibly waste paper called broke, and passed ...

See also:

Fourdrinier machine, Fourdrinier machine - Sections of the machine, Fourdrinier machine - Wet end, Fourdrinier machine - Press section, Fourdrinier machine - Dryer section, Fourdrinier machine - Calender section, Fourdrinier machine - Alternate papermaking techniques

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Soldering to gold-plated parts can be tricky. Gold dissolves in solder; an alloy of solder which contains more than 5% of gold can become brittle and the joint surface is dull-looking. If the gold layer does not completely dissolve in the solder, it may be pulled off the underlying surface later as the tin and gold atoms cross-migrate and undergo Kirkendall voiding, leading into a mechanical failure of the joint; a similar process on the gold-aluminum interface is known as purple plague. Thin layers of gold (under 20 mil) dissolve in the solder, exposing the ...

See also:

Gold plating, Gold plating - Soldering issues, Gold plating - Types of gold plating, Gold plating - Jewelry

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The Solvay process produces sodium carbonate from salt (sodium chloride) and limestone (calcium carbonate). In neutral or basic solutions, sodium bicarbonate is less water-soluble than sodium chloride. When carbon dioxide passes through a concentrated solution of sodium chloride and ammonia, sodium bicarbonate precipitates according to the following chemical reaction: NaCl + CO2 + NH3 + H2O → ...

See also:

Solvay process, Solvay process - Chemistry, Solvay process - Uses, Solvay process - History

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Any fusible material can be atomized. Several techniques have been developed which permit large production rates of powdered particles, often with considerable control over the size ranges of the final grain population. Powders may be prepared by comminution, grinding, chemical reactions, or electrolytic deposition. Several of the melting and mechanical procedures are clearly adaptable to operations in space or on the Moon. Powders of the elements Ti, V, Th, Nb, Ta, Ca, and U have been produced by high-temperature reduction of the cor ...

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Powder metallurgy, Powder metallurgy - History and capabilities, Powder metallurgy - Powder metallurgy in space-based manufacturing, Powder metallurgy - Powder Production Techniques, Powder metallurgy - Atomization, Powder metallurgy - Centrifugal disintegration, Powder metallurgy - Other techniques, Powder metallurgy - Powder production in space-based manufacturing, Powder metallurgy - Powder pressing, Powder metallurgy - Continuous powder processing, Powder metallurgy - Special products

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Soda ash and potash (potassium carbonate), collectively termed alkali, are vital chemicals in the glass, textile, soap, and paper industries. The traditional source of alkali in western Europe had been potash obtained from wood ashes. However, by the 1700s, deforestation had rendered this means of production uneconomical, and alkali had to be imported. Potash was imported from North America, Scandinavia, and Russia, where large forests still stood. Soda ash was imported from Spain and the Canary Islands, where it was produced from the ...

See also:

Leblanc process, Leblanc process - Background, Leblanc process - Chemistry, Leblanc process - Industrial history, Leblanc process - Pollution issues, Leblanc process - Obsolesence

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Most textbooks have it that Charles Goodyear (1800–1860) was first to use sulfur to vulcanize rubber. However we know today that ancient Mesoamericans achieved the same results in 1600 BC [2]. Depending on whom you read, the Goodyear story is either one of pure luck, or one of careful research. Goodyear insists that it was the latter, though there are many contemporaneous accounts which indicate the former. Goodyear claimed that he discovered sulfur-based vulcanization in 1839, but did not patent the invention until July 5, 1 ...

See also:

Vulcanization, Vulcanization - Reason for vulcanizing, Vulcanization - Description, Vulcanization - Overview and history, Vulcanization - Goodyear's contribution, Vulcanization - Subsequent developments

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An ionic compound is dissolved with an appropriate solvent, or otherwise melted by heat, so that its ions are available in the liquid. An electrical current is applied between a pair of metal electrodes immersed in the liquid. The negatively charged electrode is called the cathode, and the positively charged one the anode. Each electrode attracts ions which are of the opposite charge. Therefore, positively charged ions (called cations) move towards the cathode, while negatively charged ions (termed anions) move toward the anode. The energy r ...

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Electrolysis, Electrolysis - Overview, Electrolysis - Electrolysis of water, Electrolysis - Experimenters, Electrolysis - First law of electrolysis, Electrolysis - Second law of electrolysis, Electrolysis - Industrial uses, Electrolysis - Military uses

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Forge - Coal/coke/charcoal forge. A forge which typically uses bituminous coal, industrial coke or charcoal as the fuel to heat metal. The designs of these forges have varied over time and circumstances for thousands of years but whether the fuel is coal, coke or charcoal the basic design has remained the same. The illustration at the beginning of this article shows a coal forge in operation. A forge of this type is essentially a hearth or fireplace designed to allow a fire to be controlled such tha ...

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Forge, Forge - Forging, Forge - Types of forges, Forge - Coal/coke/charcoal forge, Forge - Gas forge, Forge - Drop forge, Forge - Hydraulic Press Forge

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The reaction of nitrogen and hydrogen (1) is reversible, meaning the reaction can proceed in either the forward or the reverse direction depending on conditions. The forward reaction is exothermic, meaning it produces heat and is favored at low temperatures. Increasing the temperature tends to drive the reaction in the reverse direction, which is undesirable if the goal is to produce ammonia. However, reducing the temperature reduces the rate of the reaction, which is also undesirable. Therefore, an intermediate temperature high enough to allow the reaction to proceed at a reasonable rate, yet not so h ...

See also:

Haber process, Haber process - Equilibrium and the Haber Process, Haber process - Links

Read more here: » Haber process: Encyclopedia II - Haber process - Equilibrium and the Haber Process

An ionic compound is dissolved with an appropriate solvent, or otherwise melted by heat, so that its ions are available in the liquid. An electrical current is applied between a pair of metal electrodes immersed in the liquid. The negatively charged electrode is called the cathode, and the positively charged one the anode. Each electrode attracts ions which are of the opposite charge. Therefore, positively charged ions (called cations) move towards the cathode, while negatively charged ions (termed anions) move toward the anode. The energy r ...

See also:

Electrolysis, Electrolysis - Overview, Electrolysis - Electrolysis of water, Electrolysis - Experimenters, Electrolysis - First law of electrolysis, Electrolysis - Second law of electrolysis, Electrolysis - Industrial uses, Electrolysis - Domestic uses, Electrolysis - Military uses

Read more here: » Electrolysis: Encyclopedia II - Electrolysis - Overview

The Leblanc process plants were decidedly not environmentally friendly. The process of generating salt cake from salt and sulfuric acid released hydrochloric acid gas, and because this acid was industrially useless in the early 1800s, it was simply vented into the atmosphere. In addition, for every 8 tons of soda ash, the process produced 7 tons of calcium sulfide waste. This solid waste had no economic value, and was piled in heaps and spread on fields near the soda works, where it weathered to release hydrogen sulfi ...

See also:

Leblanc process, Leblanc process - Background, Leblanc process - Chemistry, Leblanc process - Industrial history, Leblanc process - Pollution issues, Leblanc process - Obsolesence

Read more here: » Leblanc process: Encyclopedia II - Leblanc process - Pollution issues