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Plant Nutrition and Turf Fertilizers
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
The second and most widely used method is based on the neutralization of phosphoric acid with ammonia to produce ammonium polyphosphates. Considerable heat is generated and the solution becomes hot during this process. Anhydrous or aqueous ammonia, or ammonia-ammonium nitrate, or ammonia-urea type N solutions are reacted with phosphoric acid solutions followed by the addition of solid sources of N and/or potash. Aqueous ammonia also is reacted with sulfate and elemental sulfur to form 12-0-0-26S ammonium thiosulfate. It can be used in a wide variety of N-P-K-S formulations and is essentially noncorrosive. The density of most common liquid mixtures will approximate 10 pounds/gallon (1.2 kg/L).
Chelate assisted phytoextraction for effective rehabilitation of heavy metal(loid)s contaminated lands
Published in International Journal of Phytoremediation, 2023
Akshaya Prakash Chengatt, Nair G. Sarath, Delse Parekkattil Sebastian, N. Shibin Mohanan, E. S. Sindhu, Satheesh George, Jos T. Puthur
Phytoextraction studies were conducted on Lepidium sativum, and Brassica juncea using sodium thiosulfate and ammonium thiosulfate, respectively for cleaning mercury-contaminated soil showed that sodium thiosulfate did not affect the biomass of plants but increased mercury accumulation and translocation to shoots (Smolinska and Rowe 2015; Grifoni et al. 2017; Wang et al.2017). A similar study on the plant Austrodanthonia caespitosa also had similar results. All these studies concluded that ammonium thiosulfate increased the plant’s ability of Hg accumulation (Lomonte et al.2011). The higher accumulation in plants may be attributed to the easier passage of the Hg-thiosulfate complex through the endodermis to the xylem. The Hg ions can easily combine with thiosulfate and form soluble complexes that are easier for the plants to absorb (Wang et al.2011; Liu et al.2014). A study by Makarova et al. (2021) confirmed that sulfur-containing chelant monoethanolamine salt of dithiobiacetic acid (MEDBA) could enhance the Hg phytoextraction of Trifolium repens. The increased efficiency of the plant can be due to the high tendency of mercuric ions to complex with the sulfur-containing ligands (Wang et al.2012).
Hydrometallurgical processes for heavy metals recovery from industrial sludges
Published in Critical Reviews in Environmental Science and Technology, 2022
Viraj Gunarathne, Anushka Upamali Rajapaksha, Meththika Vithanage, Daniel S. Alessi, Rangabhashiyam Selvasembian, Mu. Naushad, Siming You, Patryk Oleszczuk, Yong Sik Ok
Thiosulfate solutions can be used as an alternative to cyanide-based leaching solutions that are highly toxic and are known to lead to potentially severe environmental consequences. Thiosulfate leaching is highly effective for recovering Au and Ag, which are found in waste materials resulting from the cell phone industry in considerable amounts (Abbruzzese et al., 1994). Therefore, this leaching technique is suitable for the treatment of wastewater sludge resulting from the mobile phone manufacturing industry. The primary benefit of using thiosulfate for the recovery of valuable metals is that it solubilizes the targeted metals by making recoverable complexes while resulting in less interference with other cationic species (Abbruzzese et al., 1995). Solvents such as ammonium thiosulfate or sodium thiosulfate solutions solubilize Au, Ag, Pt, and other metals in the form of stable anionic complexes over a wide range of pH. The ammonia in the “pregnant solution” (i.e., the acidic metal-laden solution that results from the leaching process) stabilizes the complex by inhibiting the formation of further oxides of metals (i.e., Au to Au(I)) (Abbruzzese et al., 1995; Ubaldini et al., 2000). Two forms of thiosulfates, sodium and ammonium thiosulfate, have been effectively employed to recover Au from waste materials. These solutions are nontoxic, non corrosive, and moderately stable in alkaline conditions. However, the requirement of the solvent is considerably high as compared with other leaching solvents.
A review of Preg-robbing and the impact of chloride ions in the pressure oxidation of double refractory ores
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Wei Sung ng, Qiankun wang, Miao chen
Early commercialization in Mexico was reported by Qian and Jiexue (1989); however, the treatment plant could not be run to specifications, potentially due to the selection of an incorrect operating pH. This may have left an unfavorable impression on the industry, as practical application in the following years has been limited to heap leaching (Wan, LeVier and Clayton 1994). Newmont employed bio-oxidation followed by thiosulfate leaching for the heap treatment of preg-robbing refractory ores (Bouffard and Dixon 2004; Brierley and Brierley 1999; Brierley and Kulpa 1993), reporting gold recoveries above 70% with leaching at pH 9.2– 10.0 using 60 ppm of copper(II) ammonia complex as a catalyst, and 0.1– 0.2 M ammonium thiosulfate or sodium thiosulfate and ammonia as a leaching reagent (Wan and Brierley 1997). An alternative pressure oxidation-thiosulfate leaching-resin recovery setup was patented by Thomas et al. (1998), although the technique is more suitable for low copper ores due to the absence of resin selectivity between gold and copper (Aylmore and Muir 2001).