Schematic drawing of a puddling furnace

The puddling furnace is a metalmaking technology to create wrought iron from the pig iron produced in a blast furnace. Pig iron contains high amounts of carbon and other impurities, making it brittle. The puddling furnace burns off these impurities to produce a malleable low-carbon steel. It is the process of manually handling and stirring the iron during and after this process that gives us the name "wrought". Invented by Peter Onions and patented by Henry Cort in 1783-4, the puddling process, along with the blast furnace, led to a massive increase in the amount of iron being produced every year. Schematic drawing of a puddling furnace. ... Schematic drawing of a puddling furnace. ... Technology (Gr. ... Wrought iron is a very pure form of commercial iron, having a very small carbon content. ... Pig iron is raw iron, the immediate product of smelting iron ore with coke and limestone in a blast furnace. ... A blast furnace is a type of furnace for smelting whereby the combustion material and ore are supplied with air from the bottom of the chamber such that the chemical reaction does not take place only at the surface. ... A patent is a set of exclusive rights granted by a government to a person for a fixed period of time in exchange for the regulated, public disclosure of certain details of an invention. ... During the Industrial Revolution in England, Henry Cort began refining iron from pig iron to wrought iron using innovative production systems. ...

The furnace was constructed to pull the hot air over the iron without it coming into direct contact with the fuel, a system generally known as a reverberatory furnace or open-hearth process. After lighting and being brought to a low temperature, the furnace is prepared for use by "fettling", painting the grate and walls around it with iron oxides, typically hematite. Iron is then placed on the grate, normally about 600 lbs, and allowed to melt on top, mixing with the oxides. The mixture is then stirred vigourously with a "rabbling-bar", a long iron rod with a hook formed into one end. This causes the oxygen from the oxides to the mix to react with various impurities in the pig iron, notably silicon, manganese and to some degree sulfur and phosphorus, which form gases and are removed out the chimney. A reverbatory furnace reflects heat (reverberates it) off a surface of refractory brick onto a material to be heated. ... Hematite (AE) or haematite (BE) is the mineral form of Iron (III) oxide, (Fe2O3), one of several iron oxides. ... Officially the pound is the name for at least three different units of mass: The pound (avoirdupois). ... General Name, Symbol, Number Oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16 (VIA), 2, p Density, Hardness 1. ... General Name, Symbol, Number silicon, Si, 14 Series metalloid Group, Period, Block 14 (IVA), 3, p Density, Hardness 2330 kg/m3, 6. ... General Name, Symbol, Number manganese, Mn, 25 Chemical series transition metals Group, Period, Block 7 , 4, d Density, Hardness 7470 kg/m3, 6. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16 (VIA), 3, p Density, Hardness 1960 kg/m3, 2 Appearance Lemon yellow at STP Atomic properties Atomic weight 32. ... This article is about the chemical element. ... Chimney stacks on a Newcastle upon Tyne building A chimney is a system for venting hot gases and smoke from a stove, furnace or fireplace to the outside atmosphere. ...

More fuel is then added and the temperature raised. The iron completely melts and the carbon starts to burn off as well. The carbon dioxide formed in this process causes the slag to "puff up" on top, giving the rabbler a visual indication of the progress of the combustion. As the carbon burns off the melting temperature of the mixture rises, so the furnace has to be continually fed during this process. Eventually the carbon is mostly burned off and the iron forms into a spongy plastic material, indication that the process is complete and the material can be removed. General Name, Symbol, Number Carbon, C, 6 Chemical series Nonmetals Group, Period, Block 14 (IVA), 2, p Density, Hardness 2267 kg/m3 0. ... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ... This article is about the mining or chemical term. ...

The hook on the end of the bar is then used to pull out large "puddle-balls" of the material, about 40 kg each. These are then hammered using a steam hammer to weld shut internal cracks, while breaking of chunks off impurities. The iron is then re-heated and rolled out into flat bars or round rods. The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... The steam hammer is a power-driven hammer used in forgings. ...

The puddling furnace was widely used as the first step in making crucible steel as well. The low-carbon wrought iron was packed in large stone boxes with a layer of charcoal powder between each bar, heated to very high temperatures for six days (plus two days for the furnace to heat up and another two to cool down before the metal could be removed) so that some of the carbon from the charcoal was transferred cleanly into the iron. The bars were then broken into small pieces, and melted in crucibles to produce steel. Crucible steel describes a number of different techniques for making steel alloy by slowly heating and cooling iron and carbon (typically in the form of charcoal) in a crucible. ...

Both processes, and the puddling furnace, were displaced with the introduction of the Bessemer Process, which produced similar quality steels for a fraction of the cost and time. For comparison, an average size charge for a puddling furnace was 600 lbs, for a Bessemer converter it is 15 tons. Wrought iron is now made from the Bessemer Process as well. Still-liquid steel from the converter is mixed with oxides and stirred as in the former process, lowering the carbon content. The mixture is then poured into a cooler container, where is solidifies almost instantly, shattering as a result, and thereby releasing the combustion gases trapped inside. The resulting low-carbon spongy metal is then hammered and rolled as before. Bessemer Converter, Schematic Diagram The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron. ... The word ton or tonne is derived from the Old English tunne, and ultimately from the Old French tonne, and referred originally to a large cask with a capacity of 252 wine gallons, which holds approximately 2100 pounds of water. ...