Journal of Fluorine Chemistry ( IF 1.9 ) Pub Date : 2018-03-29 , DOI: 10.1016/j.jfluchem.2018.03.018 L.P. Ramteke , A.C. Sahayam , A. Ghosh , U. Rambabu , M.R.P. Reddy , K.M. Popat , B. Rebary , D. Kubavat , K.V. Marathe , P.K. Ghosh
Fluoride levels in seven commercial phosphate fertilizers (four single superphosphate samples, two diammonium phosphate samples, and one ammonium nitrophosphate sample) were analyzed independently at three laboratories employing the techniques of ion chromatography and ion-selective electrode. The results were consistent for aqueous solutions containing 100 mg L−1 (ppm) of fertilizer. The average values of fluoride from four different studies varied from 0.140 ± 0.006–1.33 ± 0.158% (w/w) for the seven fertilizer samples. The [P2O5]/[F] ratios (w/w) were computed for all the seven samples and the values were in the range of 13.79–328.57. By comparing these values with the average [P2O5]/[F] ratio in phosphate rock, it was inferred that 3–75% of fluoride originally present in rock remained in the fertilizers. IR spectral data revealed a small peak at 716 cm−1 – indicative of SiF62− – in the sample containing lowest fluoride which may be on account of fluoride stripping of intermediate phosphoric acid with reactive silica in this case. Considering 15 MMT (million metric tons) of annual consumption of phosphate fertilizers in India, the incremental load of fluoride in agricultural fields was estimated to be 127,650 ± 14,550 MTy−1 based on the grand average fluoride content of 0.851 ± 0.097% (w/w). While a part of this fluoride would likely get discharged into oceans through run-off, the remainder may persist in the soil, some amount may accumulate in vegetation, and a part might find its way into fresh water bodies, thereby aggravating the fluoride problem in the Country. The problem of non-point source pollution can be reduced by eliminating fluoride at source, and utilizing the recovered fluoride as feedstock. This could, in principle, satisfy the entire requirement of the fluorochemicals industry in India. Environmental costs need to be factored in while making an assessment of the viability of fluoride recovery and reuse in this manner compared to production from virgin sources of fluoride.
中文翻译:
一些商业磷酸盐肥料中氟化物含量的研究
在三个实验室采用离子色谱和离子选择电极技术分别分析了七种市售磷酸盐肥料(四个单一的过磷酸钙样品,两个磷酸二铵样品和一个硝酸磷酸铵样品)中的氟化物含量。对于含有100 mg L -1(ppm)肥料的水溶液,结果是一致的。四个不同研究的氟化物的平均值在七个肥料样本中为0.140±0.006-1.33±0.158%(w / w)。计算所有七个样品的[P 2 O 5 ] / [F]比(w / w),其值在13.79–328.57范围内。通过将这些值与平均值[P 2磷矿石中的O 5 ] / [F]比可以推断出,最初存在于岩石中的氟中有3–75%残留在肥料中。红外光谱数据显示,在含最低氟化物的样品中,在716 cm -1处有一个小峰,表明SiF 6 2-,这可能是由于在这种情况下用反应性二氧化硅对中间磷酸进行了氟化物汽提。考虑到印度磷肥每年消耗1500万吨(万吨),在农业领域的氟化物增量负荷估计为127650±14550 MTY -1的基础上0.851±0.097%的总平均氟含量(W / w)。尽管这种氟化物的一部分可能会通过径流排放到海洋中,但其余部分可能会残留在土壤中,有些可能会在植被中积累,而一部分可能会进入淡水体,从而加剧了氟化物的问题。国家。通过从源头消除氟化物并利用回收的氟化物作为原料,可以减少面源污染的问题。原则上,这可以满足印度氟化物行业的全部需求。与原始的氟化物生产相比,在评估这种方式回收和再利用氟化物的可行性时,需要考虑环境成本。