Method for producing superphosphate by utilizing low-grade phosphate ore mixed acid process

The invention relates to a method for producing superphosphate by utilizing a low-grade phosphate ore mixed acid process. The method for producing superphosphate by utilizing the low-grade phosphate ore mixed acid process comprises the following steps: blending dilute phosphoric acid with sulphuric acid into mixed acid of sulphuric acid and phosphoric acid with sulphuric acid concentration of 60-65%, carrying out reaction on low-grade ground phosphate rock in a mixer to form slurry, enabling the slurry to flow into a formation chamber to be solidified, and then curing, so that the superphosphate target product is obtained. The method for producing the superphosphate by utilizing the low-grade phosphate ore mixed acid process has the advantages that a right amount of dilute phosphoric acid is added in sulphuric acid participating in decomposition of ground phosphate rock in advance, insufficiency in grade of phosphate rock is made up, and the superphosphate product obtained through reaction can meet fertilizer nutrient requirement, so that effective utilization of low-grade phosphate rock resource is realized; and besides, an existing superphosphate production line and public works can be utilized, investment is saved, and production and management costs are reduced.