A kind of non-phosphate precipitation wet phosphoric acid purification method

Abstract

The invention discloses a non-phosphate precipitation wet phosphoric acid purification method, which belongs to the field of phosphorus chemical industry. The non-phosphate precipitation method wet-process phosphoric acid purification technology is to use the chemical agent to combine with the anion and cation of dilute phosphoric acid to form an insoluble double salt, which is precipitated in the form of non-phosphate, so as to achieve the purpose of wet-process phosphoric acid purification and meet the requirements of high-concentration production. Requirements for phosphate fertilizers, water-soluble fertilizers and industrial-grade phosphate products. The method is stable in removing iron, magnesium, aluminum, arsenic, lead, sodium, potassium, and sulfate radicals in wet-process phosphoric acid, and has simple reaction conditions, short process flow, wide range of reagent sources, low treatment cost, and P 2 o 5 With the characteristics of high recovery rate, it realizes the one-step dilute acid "removal of half and half + weight removal + desulfurization". After treatment, the removal rates of wet-process iron phosphate, magnesium, and aluminum are over 97%, 70%, and 15% respectively. The arsenic and lead in dilute acid are less than 5ppm, and sodium (calculated as NaO) and potassium (calculated as K 2 O meter) respectively less than 0.025%, 0.083%, sulfate less than 0.16%, P 2 o 5 The recovery rate is higher than 98.5%.

Description

technical field [0001] The invention relates to a method for purifying non-phosphate precipitation wet phosphoric acid, which belongs to the field of phosphorus chemical industry. Background technique [0002] my country is rich in phosphate rock resources, and its reserves rank second in the world, second only to Morocco. Although the total reserves of phosphate rock in my country are very large, most of them belong to low-grade ore, and the ore contains a lot of impurities, which is a typical type of refractory low-activity phosphate rock. Wet-process phosphoric acid is an important intermediate product for the production of phosphate products, and provides important raw materials for phosphorus chemical industry, metallurgy, medicine, food, military industry and other industries. At present, there are two main production methods of phosphoric acid: thermal method and wet method. The first thermal phosphoric acid is to use the electric furnace method to produce yellow ph...

AI Technical Summary

Problems solved by technology

However, there are more prominent problems in wet-process phosphoric acid: with the depletion of phosphate rock grade, the impurity content in phosphate rock is increasing. During the extraction reaction process between sulfuric acid and phosphate rock, such as Fe 2+ / 3+ 、Al 3+ , Mg 2+ , F - Harmful impurities and other harmful impurities enter the phosphoric acid extract together, resulting in a decline in the quality of phosphoric acid products

Disadvantages: high phosphorus loss rate, insufficient purification depth, and the introduction of other ions at the same time, bringing new troubles to deep purification

Disadvantages: The separation of phosphoric acid and solvent requires distillation, which consumes a lot of energy (except for back extraction with alkali), and there is a certain loss during solvent recovery, and the removal rate of impurities is not high