Method for producing monoammonium phosphate by metathesis method

Abstract

The invention provides a method for manufacturing ammonium diacid phosphate by double decomposition, which follows the steps of material preparation by computation, calcium superphosphate preparation, double decomposition reaction, PH value vernier regulation and drying and grinding in sequence. The invention is remarkably characterized by that calcium superphosphate is prepared by firstly using rock phosphate and sulfuric acid and then carried out the double decomposition reaction with ammonium sulfate to manufacture ammonium diacid phosphate products, which avoids the defect in traditional 'neutralization method' that large quantity of metal ion such as iron, aluminum and magnesium are precipitated as the form of hydrogen phosphate of water insoluble and large quantity of phosphorus element are drained away; the thickness of hydrogen ion in original state of reaction liquid and the water solubility of dihydric phosphate such as iron, aluminum and magnesium are preserved. The method can use low, middle and high grade of phosphorite as material and manufacture ammonium diacid phosphate products with a quality that can realize or higher than the international II class standard; the total yield of phosphorus reaches up to 95 percent; the consumption of sulfuric acid material reduces by 30 percent; the method has a good effect of energy saving and emissions reduction and remarkable economic efficiency.

Description

Technical field: [0001] The invention relates to the technical field of producing monoammonium phosphate, in particular to a method for producing monoammonium phosphate by metathesis. Background technique: [0002] Monoammonium phosphate is also known as ammonium dihydrogen phosphate, and its chemical formula is NH 4 h 2 PO 4 , it is an ammonium phosphate compound fertilizer that has been used in agricultural production for a long time and plays an important role in ensuring crop production and harvest. In addition to being used as a chemical fertilizer, as an important phosphate chemical product, it can also be used as a fire extinguishing flame retardant and a chemical additive. It has been widely used in many production technology fields such as agricultural production, food manufacturing, and chemical medicine. So far, in the phosphate chemical industry, fertilizer phosphoric acid and NH 3 The process technology of neutralization reaction is used to produce monoammon...

AI Technical Summary

Problems solved by technology

[0003] (1) Phosphoric acid and NH in fertilizer 3 In the process of neutralization reaction, especially when the reaction solution is from pH 1.5 to pH 4.5, a large number of metal ions such as iron, aluminum and magnesium in fertilizer phosphoric acid will be in the form of water-insoluble hydrogen phosphate Precipitation and loss of a large amount of phosphorus will seriously affect the yield of total phosphorus

According to survey statistics: the total phosphorus yield of the current "neutralization method" to produce monoammonium phosphate is generally only about 80%.

[0004] (2) Existing manufacturers who use the "neutralization method" to produce monoammonium phosphate can only use high-grade phosphorus in order to make the product meet the technical index of "water-soluble phosphorus accounting for ≥ 75% of available phosphorus" stipulated in the national standard II Mines are used as raw materials for production, which is contrary to the basic national policy of comprehensive utilization of resources and sustainable development

[0005] (3) Using the "neutralization method" process to produce 1 ton of monoammonium phosphate product needs to consume 1.3 tons of sulfuric acid raw materials. Due to the recent continuous rise in the market price of sulfur, the production cost of sulfuric acid per ton has been as high as 1600 yuan, which directly leads to the loss of monoammonium phosphate. Production costs have risen sharply

Images