硝酸酸解焙烧磷精矿过程五氧化二磷分解率及伴生碘的迁移分布研究

中低品位沉积型磷块岩磷矿需经选矿才能用于湿法磷酸生产。浮选磷精矿难以完全满足硝酸磷肥生产要求, 焙烧磷精矿更适合于硝酸磷肥生产。研究了硝酸酸解焙烧磷精矿过程工艺参数对五氧化二磷分解率及伴生碘三相迁移分布的影响, 并与硝酸酸解浮选磷精矿实验结果进行对比分析。结果表明, 酸解温度为60 ℃、酸解时间为50 min、硝酸质量分数为55% 和酸解比（硝酸与磷精矿的质量比）为1.2条件下, 焙烧磷精矿五氧化二磷分解率达到97.85%;酸解温度同为60 ℃条件下, 焙烧磷精矿的五氧化二磷分解率均高于浮选磷精矿, 而其他酸解工艺参数明显低于浮选磷精矿;两种磷矿伴生碘大部分升华至气相, 但焙烧磷精矿伴生碘更易于升华。

Study on decomposition rate of phosphorus pentoxide and migration distribution of associated iodine in acidolysis process of calcinating phosphate concentrate ore with nitric acid

The medium-low grade sedimentary phosphorite phosphate rock could only be used for production of wet phosphoric acid after beneficiation.It is difficult for flotation phosphate concentrate ore to fully meet the requirements of production of nitrophosphate while roasting phosphate concentrate is more suitable for production of nitrophosphate.The effects of technological parameters on the decomposition rate of phosphorus pentoxide and the three-phase migration distribution of associated iodine in the process of nitric acid acidolysis calcinating phosphorus concentrate ore were studied which were compared with the experimental results of nitric acid acidolysis phosphorus concentrate ore flotation.The results showed that under the conditions as follows:acidolysis temperature was 60℃,acidolysis time was 50 min,mass fraction of nitric acid was 55%and acidolysis ratio was 1.2,the decomposition rate of phosphorus pentoxide in calcinating phosphate ore concentrate reached 97.85%.At the same acidolysis temperature of 60℃,the decomposition rate of phosphorus pentoxide of calcinating phosphorus concentrate ore was higher than that of floating phosphorus concentrate ore,while other acidolysis process parameters were significantly lower than that of floating phosphorus concentrate ore.Most of the iodine associated with the two kinds of phosphate rocks sublimates to the gas phase,but the iodine associated with the roasted phosphate concentrate ore was easier to sublimate.