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Published in Guillaume Madelin, X-Nuclei Magnetic Resonance Imaging, 2022
Potassium compounds are used in many products: potassium hydroxide (KOH) is used in soaps, detergents, and drain cleaners; potassium carbonate (KHCO3) is used to make glass and soaps and is obtained commercially as a byproduct of the production of ammonia; sodium potassium (NaK) is used as a heat transfer medium in some types of nuclear reactors; potassium superoxide (KO2), which can create oxygen from water vapor H2O and carbon dioxide CO2, is used in respiratory equipment; and potassium nitrate (KNO3), also known as saltpeter or niter, is used in fertilizers, match heads, pyrotechnics, and explosives. As heavy crop production rapidly depletes the soil of potassium, potassium fertilizers containing potassium chloride (KCl) are intensively used in agriculture and account for about 95% of global potassium chemical production.
Historical Adventures in Chemical and Biomolecular Engineering
Published in Victor H. Edwards, Suzanne Shelley, Careers in Chemical and Biomolecular Engineering, 2018
Victor H. Edwards, Suzanne Shelley
At the same time, there was increasing demand for nitrogen-containing feedstocks to supply the burgeoning chemical industry. At that time, mining of niter (sodium nitrate) deposits was typically the primary source of nitrogen for these two critical products. Several industrial processes were developed during the nineteenth century to synthesize ammonia (NH3) from air and hydrogen. Ammonia is a key feedstock that is needed to produce both nitrogen fertilizers and nitrogen-based chemicals—but these early processes were inefficient, costly, and hazardous.
Orange, Yellow, Brownish Stains and Alteration on White Marble at El Montazah in Alexandria, Egypt
Published in International Journal of Architectural Heritage, 2021
On the other side, the X-ray analysis of two samples from stain areas (light brown, orange and yellow) on the marble statues essentially consists of higher content of calcium mineral (70.82% to 85.25%) which reflected the original composition of marble, variable amounts of gypsum; spheniscidite (NH4)(Fe, Al)2 (PO4)2 OH.2(H2O); hexahydrite MgSO4.6(H2O); niter KNO3; sulfur, orthoclase; halite; northupite Na3 Mg(CO3)2 Cl; chondrodite (Mg, Fe)5(SiO4)2(F,OH)2, zemkorite (Na,K)2Ca(CO3)2; chegemite Ca7(SiO4)3(OH)2; plattnerite (PbO2). Accordingly, the lower content of the iron oxides and iron sulfide in marble statues on stain area, the iron alteration is not solely responsible about marble stains. In the stain samples from marble statues different alkaline compounds were detected, such as Niter, zemkorite, chegemite and spheniscidite; thus, reacting with organic matter such as carbon, decay microorganisms and Paraloid B-72 (acrylic polymer) and form color solutions, migrate and evaporate on the marble surface and leave stains. In addition, calcium, sodium, magnesium, potassium and ammonium can be converted to their nitrate, sulfates and sulfides such as niter, spheniscidite, hexahydrite, zemkorite, northupite by the action of groundwater, rainwater and dissolved gases. These compounds may be responsible for brown-yellow stains which appear on the marble statues.