Phosphorus removal from iron

Fytianos, K., E. Voudrias, and N. Raikos (1998). Modelhng of phosphorus removal from aqueous and wastewater samples using ferric iron. Environ. Pollut. 101, 1, 123-130. 

X-ray analysis of corrosion products and deposits removed from internal surfaces showed 68% iron, 12% phosphorus, 8% silicon, 3% sulfur, and 2% each of zinc, sodium, chromium, and calcium other materials made up the remainder of deposits and corrosion products. 

Ca +, Fe + etc. which are the cationic species in the slag phase). Fellner and Krohn (1969) have shown that the removal of phosphorus from iron-calcium silicate slags is accurately described by the Flood-Grjotheim equation widr... 

Perrin A modification of the Bessemer process which accomplishes the removal of phosphorus from iron by treating the initial molten metal with a molten mixture of lime, alumina, and fluorspar. 

The major ions are removed from seawater by a variety of biogeochemical processes. These processes collectively operate at slower rates than those acting on the biolimited and particle-scavenged elements, such as phosphorus and iron. This causes the major ions to spend very long periods of time dissolved in seawater before being removed to the sediments. 

Sensing sodium The /1-aluminas (see Section 4.5.3) can be successfully exploited as a sodium sensor. Sodium is widely used in the metallurgical industry, for example for removing arsenic and antimony from zinc and lead, for removing the same two elements and oxygen from copper, and phosphorus from iron. It is also added to aluminium-silicon alloys to control microstructure and, in consequence, mechanical properties. 

The preparation of violet phosphorus may conveniently be carried out as follows —The air is displaced, by means of carbon dioxide, from a hard glass tube, which is then one quarter filled with ordinary phosphorus, the remainder of the tube containing pieces of lead, preferably those which have served for a previous preparation. The carbon dioxide is then removed, the tube sealed on the pump, and placed inside an iron tube, the space between the walls being filled with magnesia. The whole is heated in a tube furnace for 8 to 10 hours at a moderate red heat. After opening, with the usual precautions, the crystalline phosphorus is removed from the surface and the crystals from the interior are collected after dissolving the lead in 1 1 nitric acid. 

Phosphorus extracted from sediment by NaOH has been related to non-occluded, surface-exchangeable, bioavailable forms (22). Hydrochloric acid extraction yields occluded phosphorus incorporated in hydrous metal oxides, carbonate and phosphate minerals of sediment. Hydroxylamine reagent specifically removes hydrous manganese oxides, while amorphous hydrous oxides of iron and aluminijm are removed by the oxalate reagent. Total available sediment phosphorus analyses includes sediment organic phosphorus components in addition to the inorganic portion determined by the selective extraction procedures. 

Figure 9 is important with respect to removal of iron from the surface ocean. Nitrogen and phosphorus are assimilated and removed from the surface ocean at a ratio within about a factor of 2 of the Redfield ratio (Falkowski, 2000 Karl,... 

The importance of redox effects on coupled iron-phosphorus cycling in freshwater systems has been the subject of study in applied environmental science, where phosphate removal from eutrophic natural waters and wastewaters, by sorption onto Fe-oxyhydroxide phases, has been explored as a remediation measure. Phosphate also has a pronounced tendency to sorb onto Al-oxyhydroxides, and these phases have been used in remediation of phosphate overenriched aquatic systems, as well (e.g., Leckie and Stumm, 1970). 

Refined oil usually retains little phospholipid, but damaged beans can have a significant content of phosphatidic acid, and the amount of iron in the oil is related to the amount of phosphorus (24). During deodorization, considerable amounts of sterol and tocopherol may be removed from the oil. The proportion removed depends on deodorization conditions, but a 30% to 40% decrease is not unusual (25). Much of the hydrocarbons and squalene are lost to the deodorizer distillate as well. Free fatty acids in fully refined oil are required to be <0.05% and unsaponifiable matter < 1.5% (26). 

The conversion of white phosphorus to red phosphorus is an exothermic reaction producing red phosphorus as a solid product, making heat removal from the reaction difficult. In a modem process developed by Hoescht A.G. (FRG), the conversion is carried out semi-continuously in a ball mill at 350°C. Mills with a volume of ca. 5m are filled with 3.7 t of iron shot of different diameters. The white phosphorus is... 

There is no particular a priori reason to suspect that oxygen production was any different from that in the modern ocean, except that there may have been constraints imposed by different availabilities of key nutrients such as phosphorus (Bjerrum Canfield 2002). Today, the availability of fixed nitrogen may constrain productivity on geological time scales (Falkowski 1997), but in the Archaean phosphorus removal by adsorption on iron oxides could have reduced P availability, significantly reducing productivity compared with today. 

Bessemer process /bess-e-mer/ A process for making steel from pig iron. A vertical cylindrical steel vessel (converter) is used, lined with a refractory material. Air is blown through the molten iron and carbon is oxidized and thus removed from the iron. Other impurities - silicon, sulfur, and phosphorus - are also oxidized. Irons containing large amounts of phosphorus are treated in a converter lined with a basic material, so that a phosphate slag is formed. The required amount of carbon is then added to the iron to produce the desired type of steel. The process is named for the British inventor and engineer Sir Henry Bessemer (1813-98). 

One of the most commonly used colorimetric methods is based on the adsorption of a dye by magnesium hydroxide to form a colored lake in alkali hydroxide solution. Titan yellow [methylbenzothiazole-(l, 3)-4,4 -diazominobenzene-(2,2 )-disulfonic acid] is the most widely used dye [97]. Typically, the sample is pretreated by incineration or acid extraction. Iron, aluminum, manganese, copper, zinc, nickel, and phosphorus must be removed from the sample due to interference of these elements with the color formation [97]. 

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