Tellurium is a non - metallic element recovered as a by - product of electrolytic copper refining. It is a member of the oxygen family and exhibits a number of unique chemical and psychical properties. Asarco produces tellurium at its Amarillo Copper Refinery in Texas. Stringent quality control procedures assure that Asarco's tellurium in uniformly high in quality. This sheet describes Asarco's standard products. Asarco is ready to work with individual customers to provide products that meet special requriements.The largest use of tellurium is as a trace additive in steel to improve machinability. Tellurium also helps control to debts of chill in cast iron and is added to lead to increase resistance of vibration and fatigue. Electronic applications for tellurium include thermoelelectric materials, infrared sensors, photo conductors, and photovoltaic cells. Tellurium is used in the rubber industry as an accelerator and curing agent improve high temperature properties and in the chemical industry as a catalyst .Tellurium is also used in tint glass, exploding top off a bottle, ceramics, semiconductors, used s chill control and in films to increase the speed. Crystalline tellurium has a silvery-white appearance, and when pure exhibits a metallic luster. It is brittle and easily pulverized. Amorphous tellurium is found by precipitating tellurium from a solution of telluric or tellurous acid. Whether this form is truly amorphous, or made of minute crystals, is open to question. Tellurium is a p-type semiconductor, and shows greater conductivity in certain directions, depending on alignment of the atoms. Its conductivity increases slightly with exposure to light. It can be doped with silver, copper, gold, tin, or other elements. In air, tellurium burns with a greenish-blue flames, forming the dioxide. Molten tellurium corrodes iron, copper, and stainless steel.

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Crystalline tellurium is a silvery - white color with a metallic lester, but is most of ten seen as the gray, powdery amphioxus form. Tellurium burns in air oxygen with a greenish - blue flames, forming tellurium oxide, it is unaffected by water or hydrochloric acud, but reacts with nitic acid. Tellurium is a type of semiconductor, and its conductivity increses slightly with exposure of light. Molten tellurium corrades iron, copper, and stainless steel.Tellurium is occasionaly found native, but is more often found as telluride of gold, and combined with other metals. The U.S, Canada, Peru and Japan are the largest free world produces of tellurium.

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With so many elements already found and the possibility of more being discovered, chemists needed a way to organize them. Many systems were tried in order to make some sort of pattern in their properties to match the table. The modern periodic table, based on atomic number and electron configuration, was created primarily by a Russian chemist, Dmitri Ivanovich Mendeleev, and a German physicist, Julius Lothar Meyer, both working independently. They both created similar periodic tables only a few months apart in 1869. Mendeleev created the first periodic table based on atomic weight. He observed that many elements had similar properties, and that they occur periodically, hence the name, periodic table. From this, he made the periodic law. His periodic law states that the chemical and physical properties of the elements vary in a periodic way with their atomic weights. The modern one states that the properties vary with atomic number, not weight. For example, the elements lithium, sodium, potassium, rubidium, and cesium have similar chemical properties. The elements that immediate follow them, beryllium, magnesium, calcium, strontium, and barium, also have similar chemical properties. Elements in Mendeleev's table were arranged in rows called periods. The columns were called groups. Elements of each group had similar properties. By Mendeleev's theory, they should have been perfectly arranged by increasing atomic weight. Since Mendeleev's table was based on atomic weight, some things didn't match perfectly. For example, tellurium and iodine caused Mendeleev some problems. The atomic mass of tellurium was greater than iodine according to the best estimates of that time, but they didn't fit the groups that Mendeleev devised. In fact, they should be switched to follow the groups he devised. The reason for this discrepancy is the fact that atomic number (the number of protons in an atom), not atomic weight, determines the order of the elements in the table, the basis of the modern periodic table.

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Tellurium was discovered by Franz Joseph Müller von Reichenstein, a Romanian mining official, in 1782. Reichenstein was the chief inspector of all mines, smelters and saltworks in Transylvania. He also had an interest in chemistry and extracted a new metal from an ore of gold, known as aurum album, which he believed was antimony. He shortly realized that the metal he had produced wasn't antimony at all, but a previously unknown element. Reichenstein's work was forgotten until 1798 when Martin Heinrich Klaproth, a German chemist, mentioned the substance in a paper. Klaproth named the new element tellurium but gave full credit for its discovery to Reichenstein. Tellurium is found free in nature, but is most often found in the ores sylvanite (AgAuTe4), calaverite (AuTe2) and krennerite (AuTe2). Today, most tellurium is obtained as a byproduct of mining and refining copper.

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Tellurium

Tellurium is a p-type semiconductor, and shows greater conductivity in certain directions, depending on alignment of the atoms. Its conductivity increases slightly with exposure to light. It can be doped with silver, copper, gold, tin, and other elements. In air, tellurium burns with a greenish-blue flame, forming the dioxide. Molten tellurium corrodes iron, copper, and stainless steel. Tellurium and its compounds are probably toxic and should be handled with care. Workmen exposed to as little as 0.01 mg/cu. meter of air, or less, develop "tellurium breath", which has a garlic-like odor. Twenty-one isotopes of tellurium are known, with atomic masses ranging from 115 to 135.. Natural tellurium consists of eight isotopes, one of which, Te(127), is unstable. It is present to the extent of 0.87% and has a half-life of 1.2 x 10^13 years. Tellurium improves the machinability of copper and stainless steel, and its addition to lead decreases the corrosive action of sulfuric acid to lead and improves its strength and hardness. Tellurium is used as a basic ingredient in blasting caps, and is added to cast iron for chill control. Tellurium is used in ceramics. Bismuth telluride has been used in thermoelectric devices. One such device, using two Bi-Te semiconductors, is reportedly capable of freezing or boiling water in seconds with the power from two flash-light batteries. The unit is said to be capable of bringing the temperature down to -75 C, using only two amperes of current. Tellurium with a purity of 99.7% costs about $6/lb. It is also available with purities of 99.999+% at a cost of $20 to $30/lb. Tellurium has no known biological role. It is very toxic and teratogenic. Workmen exposed to very small quantities of tellurium in the air develop "tellurium breath", which has a garlic-like odour. Tellurium burns in air or oxygen with a greenish-blue flame, forming tellurium(IV) oxide. It is unaffected by water or hydrochloric acid, but reacts with nitric acid. Tellurium is a p-type semiconductor, and its conductivity increases slightly with exposure to light. Molten tellurium corrodes iron, copper and stainless steel.

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Tellurium improves the machinability of copper and stainless steel, and its addition to lead decreases the corrosive action of sulfuric acid on lead and improves its strength and hardness. Tellurium is used as a basic ingredient in blasting caps, and is added to cast iron for chill control. Tellurium is used in ceramics. Bismuth telluride has been used in thermoelectric devices. Tellurium is also used in semiconductors, glass, films to increase the speed. World demand for tellurium is believed to have Decreased in 2001. The largest use for tellurium was as an additive to free-machining steel, about one-half of the market. Chemicals and catalyst usage made up about 25% of the market. Additives to nonferrous alloys accounted for about 10% of total use, and photoreceptor and thermoelectric applications accounted for slightly about 10%. Other uses (as an ingredient in blasting caps and as a pigment to produce various colors in glass and ceramics) were about 5% of consumption. Tellurium is used in the manufacture of rectifiers and thermoelectric devices and in semiconductors research. With other organic substances, it is employed as a vulcanizing agent in the processing of natural and synthetic rubber; and in antiknock compounds for gasoline. It is used also to impart a blue color to glass. Colloidal tellurium is an insecticide, germicide, and fungicide.

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Tellurium costs about $100/lb, with a purity of about 99.5%. Tellurium is occasionally found native, but is more often found as the telluride ofgold (calaverite), and combined with other metals. It is recovered commercially from theanode muds that are produced during the electrolytic refining of blister copper. The U.S.,Canada, Peru, and Japan are the largest Free World producers of the element.

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Here is a brief summary of the isolation of tellurium.

It is not usually necessary to make tellurium in the laboratory as it is commercially available. While there are some tellurium ores, most tellurium is made as a byproduct of copper refining. Extraction is complex since the method emplyed will depend upon what other compounds or elements are present. The first step usually involves an oxidation in the presence of sodium carbonate (soda ash).

Cu2Te + Na2CO3 + 2O2 2CuO + Na2TeO3 + CO2

The tellurite Na2TeO3 is acidified with sulphuric acid and the tellurium precipitates out as the dioxide (leaving and selenous acid, H2SeO3, in solution). Tellurium is liberated from the dioxide by dissolving in sodium hydroxide, NaOH, and electroytic reduction.

TeO2 + 2NaOH Na2TeO3 + H2O Te + 2NaOH + O2

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Pictures Below:

The football player before is mr. Tellurium. I made a football player becasue the element tellurium is active.

Like for example, if you place it in a bottle, the cord will fly off before you know it. I also drew a flower vase

becuase a vase is a type of ceramic and tellurium is used in ceramics.

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