The phosphorus-sulfur two-step production process was developed in the wet-process phosphoric acid industry to solve phosphogypsum pollution. However, phosphate rock acid-insoluble residue is produced during this process as a new type of solid waste, which had a high potential for recycling. For process reasons, this type of residue still contains a certain amount of uorine and phosphorus, which has a massive impact on the potential uses of phosphate rock acid-insoluble residue. Therefore, X-ray photoelectron spectroscopy, Raman, electron probe spectroscopy and scanning electron microscopy were used to examine the existing form and distribution of uorine and phosphorus in phosphate rock acidinsoluble residue. The mass fraction of F and P 2 O 5 were 9.407% and 11.862%, respectively. Fluorine existed mainly in the form of uorite, uorapatite and metal uoride. Phosphorus existed mainly in the form of uoroapatite, phosphate, hydrogen phosphate and dihydrogen phosphate. The total phosphate, hydrogen phosphate and dihydrogen phosphate contents were much higher than that of uoroapatite, whereas the uoroapatite content was higher than that of uorite and metal uoride. Fluorine and phosphorus were distributed in the form of agglomerates in the phosphate rock acid-insoluble residue. Fluorine and phosphorus were partially correlated, showing a weak relationship in the high phosphorus area.

The purification efficiency of biological removal of iron and manganese was probed by pilot tests. In this experiment, the raw water were iron concentration of 0.96~5.56 mg/L, manganese concentration of 0.87~2.38 mg/L, dissolved oxygen of 2~4 mg/L, pH value neutral. In the condition of filter speed of 6 m/h, the average removal rate of iron and manganese reached 97.6% and 90.9% respectively, the effluent concentration of Fe2+ and Mn2+ were keep in below 0.1 mg/L.

The phosphorus-sulfur two-step production process was developed in the wet-process phosphoric acid industry to solve phosphogypsum pollution. However, phosphate rock acid-insoluble residue is produced during this process as a new type of solid waste, which had a high potential for recycling. For process reasons, this type of residue still contains a certain amount of fluorine and phosphorus, which has a massive impact on the potential uses of phosphate rock acid-insoluble residue. Therefore, X-ray photoelectron spectroscopy, Raman, electron probe spectroscopy and scanning electron microscopy were used to examine the existing form and distribution of fluorine and phosphorus in phosphate rock acid-insoluble residue. The mass fraction of F and P2O5 were 9.407% and 11.862%, respectively. Fluorine existed mainly in the form of fluorite, fluorapatite and metal fluoride. Phosphorus existed mainly in the form of fluoroapatite, phosphate, hydrogen phosphate and dihydrogen phosphate. The total phosphate, hydrogen phosphate and dihydrogen phosphate contents were much higher than that of fluoroapatite, whereas the fluoroapatite content was higher than that of fluorite and metal fluoride. Fluorine and phosphorus were distributed in the form of agglomerates in the phosphate rock acid-insoluble residue. Fluorine and phosphorus were partially correlated, showing a weak relationship in the high phosphorus area.