Barium natural deposits

Barium 2 2 Increase in blood pressure Discharge of drilling wastes discharge from metal refineries erosion of natural deposits... 

The raw minerals mined from natural deposits comprise mixtures of different specific minerals. An early step in mineral processing is to use crushing and grinding to free these various minerals from each other. In addition, these same processes may be used to reduce the mineral particle sizes to make them suitable for a subsequent separation process. Non-ferrous metals such as copper, lead, zinc, nickel, cobalt, molybdenum, mercury, and antimony are typically produced from mineral ores containing these metals as sulfides (and sometimes as oxides, carbonates, or sulfates) [91,619,620], The respective metal sulfides are usually separated from the raw ores by flotation. Flotation processes are also used to concentrate non-metallic minerals used in other industries, such as calcium fluoride, barium sulfate, sodium and potassium chlorides, sulfur, coal, phosphates, alumina, silicates, and clays [91,619,621], Other examples are listed in Table 10.2, including the recovery of ink in paper recycling (which is discussed in Section 12.5.2), the recovery of bitumen from oil sands (which is discussed further in Section 11.3.2), and the removal of particulates and bacteria in water and wastewater treatment (which is discussed further in Section 9.4). 

Exposure pathways for barium primarily consist of ingestion (e.g., food and water) and inhalation. Barium is relatively abundant in nature hence, most food contains small amounts of barium. Brazil nuts have very high barium concentrations (from 3 to 4000 ppm). It is also found in drinking water from natural deposits in certain regions. Barium is also detected in the air of most cities. 

Strontianite is the naturally occurring form of strontium carbonate. It has a theoretical strontium oxide content of 70.2%, but no economically workable deposits are known. There are some naturally occurring strontium—barium and strontium—calcium isomorphs, but none has economic importance. 

Barite [13462-86-7], natural barium sulfate, BaSO, commonly known as barytes, and sometimes as heavy spar, tiU, or cawk, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. Commercial deposits are of three types vein and cavity filling deposits residual deposits and bedded deposits. Most commercial sources are replacement deposits in limestone, dolomitic sandstone, and shales, or residual deposits caused by differential weathering that result in lumps of barite enclosed in clay. Barite is widely distributed and has minable deposits in many countries. 

Two possible explanations for the difference in the chemical compositions of the Besshi-type ores and zinc-rich and barium-rich EPR-type ridge ores are (1) the different site of ore deposition, and (2) the different chemical nature of ore fluids. 

Hydrogen sulphide is present in many mineral springs, and even free sulphur is occasionally found therein.2 Many metallic sulphides, for example, iron pyrites, galena, zinc blende, stibnitc and cinnabar, occur abundantly. Sulphur dioxide, sulphites, sulphuric acid and sulphates are also found in nature, more especially in waters springing from volcanic earth, whilst the sulphates of certain metals such as calcium, barium and magnesium exist in large deposits. 

The starting material for water-soluble barium compounds is fused barium sulfide produced by coke reduction of naturally occurring barite with a low silica and strontium content. Suitable barite is readily available from many deposits worldwide. 

Barium is a silvery-white metal that occurs in nature in many different forms called compounds. These compounds are solids and they do not burn well. Two forms of barium, barium sulfate and barium carbonate, are often found in nature as underground ore deposits. Barium is sometimes found naturally in drinking water and food. Because certain forms of barium (barium sulfate and barium carbonate) do not mix well with water, the amount of barium usually found in drinking water is of a small quantity. Other barium compounds, such as barium chloride, barium nitrate, and barium hydroxide, are manufactured from barium sulfate. Barium compounds such as barium acetate, barium carbonate, barium chloride, barium hydroxide, barium nitrate, and barium sulfide dissolve more easily in water than barium sulfate and barium carbonate. 

Barium is naturally occurring in many types of rock. Deposits of fossil fuels and peat may also contain high levels of barium, often in the form of barium sulfate. It has been classified in the EPA s Group D (not classifiable). Because of its presence in drinking water and some adverse health effects on humans, it is regulated by the U.S. government. 

The nature of the adsorbed monolayer depends on the interaction of the polar head group and the substrate surface. For example, if a glass microscope slide is raised up through a barium stearate monolayer spread on distilled water, the molecules in the film will be oriented with the hydrocarbon chains outwards, and hence the adsorbed film is hydrophobic 1I80. When a previously coated plate is dipped back into the surfactant-coated water, a second oriented layer will be deposited and the coated surfac m ain becomes hydrophilic as the head groups point outward. 

In 1807, Davy made an important discovery when he subjected slightly moistened potash (potassium carbonate) to electrolysis. He noticed that a silvery matter was deposited at the negative pole, while at the positive pole oxygen was liberated. Davy surmised that the silvery matter observed at the negative pole was of a metallic nature and called it potassium. In similar experiments with sodium hydroxide he also characterized the metal sodium. He then went on to electrolyze the so-called alkaline earths, which led to the isolation of magnesium, calcium, strontium and barium. Davy announced his remarkable discoveries in a series of Bakerian Lectures (he gave all in all no less than five such lectures) and his fame... 

Formation of the scale nature of inorganic deposits is caused by precipitation of a salt from the water phase of the system. This form of deposit, called scale, is the most common form of inorganic deposits. There are several different types of scales found in the paper industry. Examples are calcium carbonate, calcium sulphate, barium sulphate, aluminium hydroxide and calcium oxalate. All these precipitates are formed because the water solubility of the respective ion pairs is exceeded. 

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