中国磷资源的分级可持续开发利用

我国磷矿石平均含P₂O₅ 18%，其中中低品位磷矿占总储量的一半，且近2/3属于难选矿，而易选矿的磷灰石平均品位含P₂O₅ 6.7%，矿石量占总储量的18.52%，因此每选出1 t含P₂O₅ 30%的高品位磷矿，将产生4 t 以上的尾矿. 为延长磷矿使用寿命，郑州大学联合云天化集团开发了“郑州大学-云天化”磷资源可持续利用模式，其实质是采用不同的途径充分利用各种品级的磷矿，如通过选矿富集为含P₂O₅ 30%的商品磷矿，主要供给生产磷铵、磷酸；P₂O₅ 27%的磷矿用于无磷石膏排放的脲硫酸复肥的生产； P₂O₅ 14%~24%的磷矿可生产碱性熔融钙镁磷肥；磷矿顶板含钾页岩用于生产熔融磷钾肥；二次选矿得到的P₂O₅ 27%的磷矿用于生产过磷酸钙；二次尾矿可进一步加工成土壤调理剂；精制磷酸过程中的萃余酸用于生产包裹型缓释肥料等，有望使中国磷资源使用年限大大延长.

Sustainable Utilization of Various Grades of Phosphorus Resources in China

The average grade of phosphate ore in China is 18% of P₂O₅， but the medium and the low grade phosphate rock occupy a half of the total reserves. Nearly two thirds of the phosphate rock is difficult to mine， meanwhile the content of easily mining apatite ore accounts for 18.52% of the total reserves with the average grade of 6.7%. Therefore， selecting 1 ton of high grade phosphate rock containing 30% of P₂O₅ will produce more than 4 tons tailings. To prolong the service life of phosphate rock， Zhengzhou university and Yuntianhua group developed a sustainable utilization mode for phosphorus resources，namely “Zhengzhou University-Yuntianhua”， which made full use of various grades of phosphate rock in different ways， including using the commercial phosphate rock containing 30% of P₂O₅ after beneficiation to produce ammonium phosphate and phosphoric acid， using the phosphate ore containing 27% of P₂O5 to produce urea sulfuric acid compound fertilizer directly by a new clean process with no phosphor-gypsum discharged， using the phosphate rock containing 14%-24% of P₂O₅ to produce multi-nutritious alkaline fused magnesium phosphate， using the phosphate ore roof containing potassium shale to produce fused phosphate and potash fertilizer， using the phosphate ore containing 27% of P₂O₅ after two flotations to produce superphosphate， using the secondary phosphate tailings to produce soil conditioners， and using the residue acid in refined phosphoric acid production to produce coated slow-release fertilizer.