What does white phosphorus interact with. Phosphorus in nature and its industrial mining
Prevalence in nature. Mass fraction of phosphorus in the earth's crust is 0.08%. The most important phosphorus minerals found in nature are fluorapatite Ca5 (PO4) 3F and phosphorite Ca3 (PO4) 2.
Properties Phosphorus forms several allotropic modifications, which differ markedly in properties. White phosphorus is a soft crystalline substance. Consists of P4 molecules. It melts at a temperature of 44.1 ° C. Very soluble in carbon disulfide CS2. Extremely toxic and light on fire.
When white phosphorus is heated, red phosphorus is formed. It is a mixture of several modifications that have different lengths of molecules. The color of red phosphorus, depending on the method and preparation conditions, can vary from light red to purple and dark brown. Its melting point is 585-600 °.
Black phosphorus is the most stable modification. In appearance, it looks like graphite. Unlike white phosphorus, red and black phosphorus do not dissolve in carbon disulfide, they are not toxic and not flammable.
Phosphorus is chemically more active than nitrogen. The chemical activity of phosphorus depends on the allotropic modification in which it is located. So, white phosphorus is most active, and black phosphorus is the least active.
In the equations of chemical reactions, white phosphorus is usually written as P4, which corresponds to the composition of its molecules. Red and black modifications of phosphorus are usually written by the formula P. The same symbol is used if the modification is unknown or can be any.
1. Interaction with simple substances - non-metals. Phosphorus can react with many non-metals: oxygen, sulfur, halogens, phosphorus does not react with hydrogen. Depending on whether phosphorus is in excess or deficiency, phosphorus compounds (III) and (V) are formed, for example:
2P + 3Br2 = 2PBr3 or 2P + 5Br2 = 2PBr5
2. Interaction with metals. When phosphorus is heated with metals, phosphides are formed:
3Mg + 2P = Mg3P2
The phosphides of some metals can decompose with water to form gaseous phosphine PH3:
Mg3P2 + 6H2O = 3Mg (OH) 2 + 2PH3
Phosphine PH3 is similar in chemical properties to ammonia NH3.
3. Interaction with alkalis. When heating white phosphorus in an alkali solution, it disproportionates:
P4 + 3NaOH + 3H2O = PH3 + 3NaH2PO2
Getting. Phosphorus in industry is obtained from calcium phosphate Ca3 (PO4) 2, which is isolated from phosphorites and fluorapatites. The production method is based on the reaction of reduction of Ca3 (PO4) 2 to phosphorus.
Coke (carbon) is used as a reducing agent for phosphorus compounds. To bind calcium compounds, silica sand SiO2 is added to the reaction system. The process is carried out in electric furnaces (production is referred to as electrothermal). The reaction proceeds according to the equation:
2Ca3 (PO4) 2 + 6SiO2 + 10C = 6CaSiO3 + P4 + 10CO
The reaction product is white phosphorus. Due to the presence of impurities, technical phosphorus is yellow, so in industry it is called yellow phosphorus.
Phosphoric fertilizers. Phosphorus, as well as nitrogen, is an important element for ensuring the growth and vital activity of plants. Plants extract phosphorus from the soil, so its reserves must be replenished by periodically adding phosphorus fertilizers. Phosphoric fertilizers are produced from calcium phosphate, which is part of natural phosphorites and fluorapatites.
The simplest phosphate fertilizer - phosphate rock is ground Ca3 (PO4) 2 phosphate. This fertilizer is hardly soluble, it can be absorbed by plants only on acidic soils.
The action of sulfuric acid on calcium phosphate produces simple superphosphate, the main component of which is calcium dihydrogen phosphate Ca (H2PO4) 2. It is a soluble substance, and it is well absorbed by plants. The method for producing simple superphosphate is based on the reaction
Ca3 (PO4) 2 + 2H2SO4 = Ca (H2PO4) 2 + 2CaSO4
In addition to the main component, superphosphate contains up to 50% calcium sulfate, which is ballast. To increase the phosphorus content in the fertilizer, phosphorite is treated with phosphoric acid:
Ca3 (PO4) 2 + 4H3PO4 = 3Ca (H2PO4) 2
The resulting fertilizer is called double superphosphate. Another phosphorus fertilizer with a high phosphorus content is CaHPO4 · 2H2O precipitate.
Highly concentrated phosphoric fertilizers are prepared on the basis of superphosphoric acid - a mixture of polyphosphoric acids H4P2O7, H5P3O10, H6P4O13 and others. These acids are formed by heating phosphoric acid H3PO4 in vacuum.
The interaction of polyphosphoric acids with ammonia produces ammonium polyphosphates, which are used as complex nitrogen-phosphorus fertilizers.
Together with nitrogen, phosphorus is part of some other complex fertilizers, for example, ammophos NH4H2PO4 and diammophos (NH4) 2HPO4.
PHOSPHORUS(Phosphorus) - a chemical element 15 (Va) of the group of the Periodic system, atomic number 15, atomic mass 30.974. There are 23 known phosphorus isotopes 24 P - 46 P, among them one stable 31 P and only it is found in nature. The half-life of the isotope is 30 P 2.55 minutes; this is the first radioactive isotope obtained artificially in 1934 Frederick and Irene Joliot-Curie.
It is possible that phosphorus in elemental form was obtained as early as the 12th century. the Arab alchemist Alkhid Bekhil during the distillation of urine with clay and lime, this is evidenced by the ancient alchemical manuscript stored in the Paris library. However, the discovery of phosphorus is usually attributed to the ruined Hamburg merchant Hennig Brand. The entrepreneur was engaged in alchemy to get a philosopher's stone and an elixir of youth, with the help of which he could easily improve his financial situation. After evaporation of 50-60 buckets of urine (he took it in the soldiers' barracks) for two weeks and the subsequent strong calcination of the dry residue with coal and sand in a retort, Brand in 1669 was able to condense the released vapors under water and get a small amount of yellow substance. It glowed in the dark and was therefore called Brand “cold fire” (kaltes Feuer). Brand's contemporaries called this substance phosphorus because of its ability to glow in the dark (dr. Greek jwsjoroV). In general, since ancient times, “phosphors” called all substances that can emit light in the dark. So, Bologna phosphorus is widely known - barium sulfide.
In 1682, Brand published the results of his research, and now he is rightly considered the discoverer of element number 15. Phosphorus was the first element, the discovery of which is documented, and its discoverer is known.
The interest in the new substance was tremendous, and Brand took advantage of it - he demonstrated phosphorus only for money or exchanged small amounts of it for gold. Despite numerous efforts, the Hamburg merchant was never able to realize his cherished dream - to get gold from lead using “cold fire”, and therefore he soon sold the recipe for a new substance to a certain Kraft from Dresden for two hundred thalers. The new owner managed to make a much bigger fortune on phosphorus - with "cold fire" he traveled all over Europe and showed it to scientists, high-ranking and even royal people, for example, Robert Boyle , Gottfried Leibniz Karl the Second. Although the method for the preparation of phosphorus was kept a closely guarded secret, in 1682 Robert Boyle managed to get it, but he only announced his methodology at a closed meeting of the Royal Society of London. Boyle's method was made public after his death, in 1692.
For a long time, phosphorus was not considered a simple substance, and only in the 1770s did the French chemist Antoine Laurent Lavoisier in his work on the composition of air, he was able to firmly establish that phosphorus is an elementary substance.
Phosphorus in nature and its industrial production.
The phosphorus content in the earth's crust is estimated at 8 10 -2% by weight. Phosphorus is the eleventh most abundant element on Earth and is one of the twenty most common elements of the solar system. Element No. 15 was found in many types of meteorites (stone and stone-iron) and on the moon. For example, in iron meteorites, the phosphorus content ranges from 0.02-0.94% (mass.), And in various samples of the lunar soil it is 0.05-0.32% (mass.). Despite the fact that geologists classify phosphorus as an impurity element (in the rocks of most of the earth's crust its content is only 0.1%), it is rock-forming, as some rocks are composed almost entirely of phosphate minerals. In the free state, phosphorus does not occur on earth and exists in the lithosphere almost to the highest degree of oxidation, in the form of the orthophosphate ion PO 4 3-. More than two hundred minerals are known containing phosphorus in significant (more than 1%) amounts. Phosphate deposits are usually divided into three groups: apatite deposits, sedimentary phosphorites and guano deposits.
Apatity - a variety of phosphorites, they can be of either magmatic or marine (sedimentary) origin. This name was given to a group of minerals about two hundred years ago, and in Greek it means “deceptive” (ap át án), originally the mineral that was often confused with aquamarine, amethyst or olivine. Apatite minerals are represented by fluorapatite Ca 5 (PO 4) 3 F (most industrially significant), hydroxyapatite Ca 5 (PO 4) 3 (OH) and chlorapatite Ca 5 (PO 4) 3 Cl, francolite (a variety of carbonatapatite) (Ca, H 2 O) 10 (F, OH) 2 (PO 4, CO 3) 6, Wilkeite Ca 10 (OH) 2 (PO 4, SiO 4, SO 4) 6, pyromorphite Pb 10 Cl 2 (PO 4, AsO 4) 6 and many others. The largest deposits of magmatic apatite are in Russia, the countries of South Africa (the alkaline complex of Palabor), Uganda and Brazil. The world's largest magmatic apatite deposit - the Khibiny massif of nepheline syenites - lies on the Kola Peninsula, near Kirovsk. It was opened in 1926 by a group of scientists led by academician A.E. Fersman.
Most of the world's phosphorus reserves marine(sedimentary) phosphorites and their weathering products. They are believed to be of oceanic origin. In the coastal regions of the trade winds, phosphates have been deposited for a long period due to various organic and inorganic processes. The concentration of phosphorites in the field increased as a result of the slow accumulation of phosphates from the environment. The largest deposits of sedimentary phosphorites are owned by Morocco (70% of the world's phosphate reserves) and Western Sahara, USA, China, Tunisia, Kazakhstan.
Guano (Spanish: guano) - natural deposits formed during the decomposition of bones and excrement of seabirds (cormorants, gannets and pelicans), guano deposits sometimes reach one hundred million tons. Guano has been known since time immemorial, as far back as 200 BC. ancient Carthaginians used bird droppings as fertilizer. In the late 19th - early 20th century. the “Bird Islands” of Peru were discovered, so named because of the large number (about 20 million) of seabirds living there. In those days, the Peruvian government earned real income by attracting a large number of tourists to the “Bird Islands” and from the sale of huge quantities of guano as fertilizer. In the last forty years, due to the activities of Peruvian fishermen, the populations of guanoproducing birds have sharply decreased (4 times), so some of the Peruvian “Bird Islands” are now completely empty. The largest deposits of guano are located along the coasts of Africa, South America, California, Seychelles. The highly decomposed guano consists mainly of monetite CaHPO 4 and vitlokite b -Ca 3 (PO 4) 2.
World production (2002) of phosphates is 135 million tons annually. The world's largest phosphate producer is the United States (26% of global production). Development is underway in Florida (Bone Valley Formation), North Carolina, Idaho and Utah. The Kingdom of Morocco (along with Western Sahara) is the second largest producer of phosphate ore (17.3%) and the largest exporter. Phosphorites are developed in three areas: Kurribge, Yussufiya and Ben-Gerir. The main field (Khouribga) is located 120 km south of Casablanca. The total reserves of phosphorites in Morocco are 64 billion tons, explored 10 billion tons (60% of the world's explored reserves). The third largest producer is China (16.7%), and the fourth largest is Russia (10.5%). The main source of phosphorus in Russia is apatite-nepheline ores on the Kola Peninsula. For more than seventy years since the discovery of the field, more than 570 million tons of apatite concentrate have been produced. Now, 10 deposits have been explored within the Khibiny massif, the total reserves of which are 3.6 billion tons, and in general, ore reserves in the Kola Peninsula are about 20 million tons. Given that over the past time, incomplete one and a half billion tons have been mined, the reserves of apatite in Russia should be enough for many more years.
Typically, such a deposit is considered industrial, which produces at least 6,000 tons of phosphate rock per 1 ha. In open pits, phosphate is mined by scraper excavators. First, sand deposits and gangue are removed, and then phosphate ore is recovered. From quarries to concentration plants, ore can be fed (over distances of several kilometers) through steel pipes in the form of water pulp.
In seawater, all inorganic phosphorus is found only in the form of an orthophosphate anion. The average concentration of phosphorus in sea water is very small and amounts to 0.07 mg P / liter. High phosphorus content in the Andaman Islands (about 12 micromol / l). The total oceanic amount of phosphorus is estimated at 9.8 · 10 10 tons.
In the atmosphere of the Earth, phosphorus is completely absent.
