Technological process for producing high concentration nitric-phosphate fertilizer

A technology of nitrophosphate fertilizer and process method, which is applied in the field of producing high-concentration nitrophosphate fertilizer, can solve problems such as the inability to meet the quality standards of nitrophosphate fertilizer products, and achieve the effects of improving particle size and distribution, high filtration intensity and simple method

Active Publication Date: 2009-07-22
TIANJI COAL CHEM IND GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If medium and low-grade phosphate rock is used for production, the existing equipment and technology will not be able to meet the quality standards for producing nitrophosphate fertilizers with total nutrients ≥ 38% and water solubility ≥ 55%.
Therefore, it is of strategic significance to develop and utilize medium and low-grade phosphate rock to produce high-concentration nitrophosphate fertilizer technology on the basis of existing equipment

Method used

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  • Technological process for producing high concentration nitric-phosphate fertilizer
  • Technological process for producing high concentration nitric-phosphate fertilizer

Examples

Experimental program
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Effect test

Embodiment 1

[0045] The quality indicator of the phosphate rock 1 of the present embodiment: P 2 o 5 27%, CaO 42%, AI 18%, MgO 2%, Fe 2 (Al 2 O) 3 A total of 3%, other impurities; the concentration of nitric acid 2 was 58%.

[0046] This embodiment is on the basis of the technological process of known frozen nitrophosphate fertilizer production, and between calcium nitrate filtration and mother liquor neutralization, 10 steps of mother liquor depth decalcification are added, and its technological flow is shown in figure 1 ,

[0047] Nitric acid 2 and phosphate rock 1 are added to the acid hydrolysis tank 3 according to the stoichiometric ratio of 1.1:1 for acid hydrolysis, the acid insoluble matter 5 in the acid hydrolysis solution is separated by precipitation separation 4, and then the acid insoluble matter 5 is separated The solution is sent to the frozen crystallization 6, and the calcium nitrate 8 is precipitated from the acid solution through the frozen crystallization and filt...

Embodiment 2

[0050] In this embodiment, in the process of producing high-concentration nitrophosphate fertilizer according to Embodiment 1, a calcium sulfate conversion process is added, and its technological process is shown in figure 2 . Here, the conversion process of calcium sulfate 17 is mainly described, which mainly includes calcium sulfate conversion 26 , pH adjustment 28 and calcium carbonate filtration 30 . The calcium sulfate 17 of embodiment one is sent to the calcium sulfate conversion equipment to carry out calcium sulfate conversion 26, add the solution that contains ammonium carbonate 27, the concentration of this solution is 60%, the calcium sulfate in the reaction slurry is converted into calcium carbonate crystallization , the process reaction conditions are reaction temperature 70° C., stirring for 2 hours, and the reaction is shown in equation (2).

[0051] Through ammonia gas 29 in the calcium sulfate transformation process, carry out pH adjustment 28, the pH of con...

Embodiment 3

[0054] The quality index of the phosphate rock 1 of the present embodiment is different from that of embodiment one, and the quality index is: P 2 o 5 22%, CaO 45%, AI 18.7%, MgO 2.0%, Fe 2 (Al 2 O) 3 Total 3.2%, other impurities; nitric acid concentration 58%. The difference between the present embodiment and embodiment one is that when the reaction slurry classification treatment 12, by mass percentage, the reaction slurry 14 with large particles of calcium sulfate accounts for 30% of the total slurry ratio and enters the filter for sulfuric acid Calcium filter 15 and wash. The reaction slurry 13 with small particles of calcium sulfate accounts for 70% of the total slurry ratio and returns to the mother liquor depth decalcification 10 process to provide crystal seeds for calcium sulfate crystals and further grow and grow into the next classification cycle. Other process is identical with embodiment one.

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Abstract

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.

Description

technical field [0001] The invention relates to a process method for producing high-concentration nitrophosphate fertilizer, in particular to a process method for producing nitrophosphate fertilizer with a nutrient greater than 38%. technical background [0002] Nitrophosphate fertilizer is a kind of nitrogen-phosphorus compound fertilizer, which is generally produced by freezing nitrophosphate fertilizer production process with phosphate rock, nitric acid and ammonia as raw materials. The only set of nitrogen and phosphorus compound fertilizers in my country that adopts the freezing method to produce 900,000 tons per year is the Tianji brand nitrophosphate fertilizer production device. It has advanced process routes, good fertilizer varieties, and obvious agricultural effects. It plays an important role in the national economy. Judging from the current sales price of chemical fertilizers, the price per unit nutrient of nitrophosphate fertilizer is the lowest among all kinds...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C05B11/06
Inventor 荆宏健樊彩梅畅学华魏安根冯军强张凌云王志华王韵芳
Owner TIANJI COAL CHEM IND GROUP
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