Phosphorus. Phosphorus. Phosphorus. Phosphorus. Phosphorus. White Phosphorus in weapons

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1 Examples of phosphorus in food additives Cola Backing powder from Greek: (φως = light, φορέω = carry) was discovered by Henning Brand, a German pharmacist and alchemist he was searching for the Philosopher s Stone, concentrating urine by evaporation white phosphorus was formed after calcining the residue under exclusion of air white phosphorus showed an unique property phosphorescence (glowing in the dark) Phosphorescence White phosphorus was first used as a drug due to it s unique property is highly flammable and pyrophoric (self-igniting) was used for fabrication of matches fire bombs and other weapons (additive to napalm) highly toxic White in weapons 1

2 White Red phosphorus Crystalline and amorphous modifications in a density range of g/ccm are know as red phosphorus Is formed from white phosphorus by heating to 260 C for several hours under exclusion of air is highly flammable when combined with strong oxidants safety matches White phosphorus is the least stable, most reactive, more volatile, less dense and most toxic of all allotropes of phosphorus Red Black phosphorus 3 crystalline and 1 amorphous modification with a density of 2.69 g/ccm Is formed from white or red phosphorus under high pressure It is gray-black and the structure resembles to that of graphite Has semiconductor properties Red phosphorus is less reactive than the white allotrope, and it is not toxic. Black ore is the 11 th most abundant element in the lithosphere occurring as phosphate commonly as an inorganic mineral phase or as an organic molecule. rock is the only economic source for P Marine sedimentary phosphorite formed on continental shelves by oceanic upwelling of cold water enriched in nutrients (North Africa, W- USA, Mexico, Brazil, China, Vietnam) Deposits formed by disintegration of phosphorite rocks and reworking in sea and streams (Florida) Black phosphorus is the least reactive allotrope. It is thermodynamically stable below 550 C and it is not toxic. Magmatic resources: magnetite-apatite (Kiruna) apatites from nepheline syenite (Khibiny, Kola) pyroxenite and carbonatite (Palabora, SA) 2

3 ore rock Negev Phosphorite ore Minor sources include: Guano: thick accumulation of bird excreta reacting with limestone (Christmas Island, Nauru) Aluminous phosphates from weathering of phosphate rock with local significance (Senegal) Guano Recycling product: slag (Thomas converter) Earlier is CH: ground bones, but also marls and sandy layers (Gault, Gemsmättlischichten) Another source of phosphorus Apatite (Fluorapatite) From Greek apatao = I m misleading 3

4 Autunite Turquoise Nearly 400 phosphate compounds are known, but only few control phosphate concentration in natural systems exploitation Open pit mining methods with walking draglines (Florida) Coal mining-like techniques with blasting and removal by dragline/shovel (Morocco, Tunisia) Underground methods for steeply dipping deposits include room-and-pillar (North Africa) Sub-level open stoping (Kola Penninsula) Washing, crushing, sizing and flotation is common in order to increase BPL to 60 88% Magnetic separation to remove iron Slurries need screening and hydrocycloning to remove clay prior to flotation (Florida) exploitation exploitation 4

5 rock production and resources ore 80% sedimentary origin 17% igneous rocks and their weathering prod. Remainder: residual sedimentary, guano World production peaked at 166 million tons of phosphate rock 1988, subsequently falling back to ca. 140 million tons but has increased again: Economically produced phosphate ore contains 20 30% P2O5 rock production is a unique element: A key element in many physiological and biochemical processes An essential nutrient for all life forms Converts energy to a usable form for food and fiber Uptake by most living organisms from natural waters But, Low solubility of phosphate P is a limiting element for animal and plant productivity (Historically: overcome by recycling of manure) s cycle Adenosine Triphosphate (ATP); energy gain when end phosphate is released to form ADP A phosphate group is attached when a cell needs to store energy. molecular rechargeable battery 5

6 s Use of phosphates uptake by plants rich fertilizers used to dramatically increase global agricultural production ricom.com/s/videos.asp Cereals are estimated to account for 55% of fertilizer use worldwide; wheat 20%, corn 14%, rice 13%, barley 4% fertilizers Single superphosphate (SSP) Triple superphosphate (TSP) Diammonium phosphate (DAP) Monoammonium phosphate (MAP) Ground phosphate rock Phosphoric acid Finely ground phosphate rock is mixed with water and treated with sulfuric acid. The basic reaction is: Ca 5 (PO 4 ) 3 F + 5H 2 SO H 2 O 5CaSO 4 2H 2 O + 3H 3 PO 4 + HF Hydrogen fluoride reacts with silicates to fluorosilicic acid SiO 2 + 6HF H 2 SiF 6 + 2H 2 O Formation of 1 ton of P 2 O 5 as wet process acid consumes t of phosphate rock (70% BPL) By-products include 1.7 t phosphogypsum High content of P, F, Cl, U, Th, REE requires this gypsum to be treated as waste Phosphoric acid Phosphoric acid is the largest inorganic acid produced and consumed by value (and only second to sulfuric acid in terms of volume). Prices Fertilizer Feedstock of phosphates and fertilizers Cattle feed additives Food additives Detergent additives Acid cleaners Hardener for paints and varnish Synthetic rubber Etc.. rock grade expressed as %P 2 O 5 or as BLP (Bone of Lime) %P 2 O 5 x = %BLP 6

7 s in the environment Increase of phosphate content in sewage due to use of phosphate based detergents eutrophication of rivers and lakes Ban of phosphate base detergents in Switzerland (since 1985) caused a reduction of 70% of phosphate input Agricultural phosphate release to natural waters usually cannot be attributed to leaching of fertilizers But rather to increased use of phosphate-rich manure -rich manure is mainly a consequence of feeding with off-site produced cattle feed Challenges for earth scientists Improve ability to limit mobilization of phosphorus from agricultural and other human sources to natural waters Developing designer fertilizer with formulations that allow better control of phosphorus release Methods to recycle phosphorus from waste (sewage sludge and effluents) Taking advantage in low solubility of phosphate and focus research to design methods to immobilize toxic and radioactive waste Fertilizer from incinerated sewage sludge Use of sewage sluge as fertilizer is not allowed in Switzerland (since 2008) Sewage is incinerated and disposed in landfills g P per kg ash from incinerated sewage sludge 6100 t P in Switzerland per year A research project started by the Paul-Scherrer- Institute led to development of a thermochemical treatment of the ash for separation from heavy metals Result: fertilizer granulate with soluble phosphorus Cleantech Separation of urine from solid using No-mix toilets Urine accounts for 1% of total wastewater but contains 80% of nutrients The Europeans are certainly leading the way in this area, in Switzerland trials with NoMix toilets have been quite successful. Apparently the majority of the Swiss people interviewed said they had no problem with it, even the men, who had to sit down to spend a penny! 7