Technological process for producing high concentration nitric-phosphate fertilizer

The invention discloses a technique method for producing high-concentration nitric phosphate, which comprises the following steps of: adding nitric acid into phosphorus ore for acidolysis, depositing and separating acid non-soluble substance, freezing and crystallizing calcium nitrate, filtering the calcium nitrate, neutralizing the mother liquid, vaporization, pelleting and drying. The invention is characterized in that: a step of thoroughly removing the calcium of the mother liquid is arranged between the steps of filtering the calcium nitrate, and neutralizing the mother liquid. The steps comprise the following steps of: I) thoroughly removing the calcium of the mother liquid and adding sulfuric acid or ammonium sulfate; the calcium ions and the sulfate ions in the mother liquid generate dihydrate calcium sulfate crystal; II) the grading processing of reaction slurry: employing a grading device to carry out grading processing to the reaction slurry; returning the reaction slurry provided with small grain calcium sulfate to the mother liquid for thoroughly removing the calcium, and feeding the reaction slurry provided with large grain calcium sulfate to the calcium sulfate for filtering; and III) filtering and washing the filtering reaction slurry of calcium sulfate by a filter, feeding the primary filtrate and the primary lavage fluid into the working procedure of neutralizing, and returning the secondary lavage fluid to the filter. The invention has the advantage of using middle-low quality phosphorite to prepare the high-concentration nitric phosphate.