Wet process phosphoric acid purification technology of nonphosphate precipitation

Abstract

The invention discloses a wet process phosphoric acid purification technology of nonphosphate precipitation and belongs to the field of phosphorus chemical industry. According to the wet process phosphoric acid purification technology of nonphosphate precipitation, an agent is combined with anions and cations in diluted phosphoric acid to generate an indissolvable double salt which is precipitated in a form of nonphosphate, so that a purpose of wet process phosphoric acid purification is achieved, thereby satisfying the demand of producing a high-concentration phosphate fertilizer, a water soluble fertilizer and an industrial phosphate product. The method can remove iron, magnesium, aluminum, arsenic, lead, sodium, potassium, sulfate radicals and the like stably in wet process phosphoric acid and has characteristics of being simple in reaction condition, short in a process flow, wide in an agent source, low in a treatment cost, high in a P2O5 recovery rate and the like, so that sesquioxide-removal, heavy metal removal and desulfuration by a one-step method are realized. The removal rates of iron, magnesium and aluminum in the treated wet process phosphoric acid separately reaches above 97%, 70% and 15%; arsenic and lead in diluted acid are less than 5 ppm; sodium (calculated by NaO) and potassium (calculated by K2O) are separately lower than 0.025% and 0.083%; sulfate radicals are lower than 0.16%; and the P2O5 recovery rate is higher than 98.5%.

Description

technical field [0001] The invention relates to a non-phosphate precipitation wet phosphoric acid purification technology, 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...

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

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