CN-115970394-B - Filter aid for decomposing phosphate rock acidolysis solution by nitric acid and filtering method

Abstract

The invention relates to the field of filter aids, in particular to a filter aid for decomposing phosphate rock acidolysis solution by nitric acid and a filtering method. The filter aid is magnetic carbon filter aid, and the preparation method of the magnetic carbon filter aid comprises the following steps of fully mixing coal gasification coarse slag and electrolyte solution containing calcium ions, adding the mixture into a ball mill for grinding, transferring the mixture into a tubular reaction furnace, immersing a reaction product into alginic acid and amino acid iron solution, carrying out ultrasonic oscillation and centrifuging to obtain a solid product, and then placing the solid product into the tubular reaction furnace for treatment. When in filtration, humic acid is firstly added into acidolysis solution, stirred, then stood for sedimentation, and primary filter pressing is carried out to obtain primary filter residues and primary filtrate; and adding a magnetic carbon filter aid into the primary filtrate, stirring, standing for sedimentation, and carrying out secondary filter pressing. The filter aid provided by the invention can improve the acidolysis solution filtering efficiency, and the filter cake of primary filter pressing can produce organic-inorganic mixed fertilizer to purify the environment, thereby laying a foundation for improving the quality of the follow-up gypsum.

Inventors

• ZHANG QIANG
• YU NANSHU
• Xiang Lixue
• ZHENG LEI
• ZOU PENG
• QI YINGJIE
• SONG GUOFA
• XU WENHUA
• MENG XIN
• CHEN HAINING
• ZHU XIAOJIE

Assignees

• 金正大生态工程集团股份有限公司
• 金正大诺泰尔化学有限公司
• 浙江大学山东(临沂)现代农业研究院
• 菏泽金正大生态工程有限公司
• 沃夫特复合肥有限公司

Dates

Publication Date

20260505

Application Date

20221206

Claims (6)

1. 1. A filtering method for decomposing phosphate rock acidolysis solution by nitric acid is characterized by comprising the steps of carrying out filter pressing on acidolysis solution obtained by decomposing phosphate rock by nitric acid in two steps, firstly adding humic acid into acidolysis solution, stirring until the mixture is uniform, standing and settling, carrying out primary filter pressing to obtain primary filter residues and primary filtrate, then adding a magnetic carbon filter aid into the primary filtrate, wherein the specific surface area of the magnetic carbon filter aid is 300-500m 2 /g, the aperture is 20-70 microns, stirring until the mixture is uniform, standing and settling, carrying out secondary filter pressing to obtain secondary filter residues and secondary filtrate, and further comprising a regeneration step of the magnetic carbon filter aid, and roasting the secondary filter residues at 500-600 ℃ for 0.5-1h to obtain the magnetic carbon filter aid which is used for secondary filter pressing of acidolysis solution; the preparation of the magnetic carbon filter aid comprises the following steps: (1) Fully mixing coal gasification coarse slag and electrolyte solution containing calcium ions according to a solid-to-liquid ratio of 1g:6-8ml, and then adding the mixture into a plasma ball mill for grinding; (2) Transferring the ball-milled product to a tubular reaction furnace, heating to 200-500 ℃ and reacting for 1-3h in a steam atmosphere; (3) Immersing the reaction product obtained in the tubular reaction furnace in the step (2) in alginic acid and amino acid iron solution according to the solid-to-liquid ratio of 1g to 10-20ml, ultrasonically oscillating for 1-3h, and centrifugally separating to obtain a solid product; (4) The solid product is put into a tubular reaction furnace to be heated and dried, the temperature is 300-600 ℃ and the time is 1-2h.
2. 2. The method for filtering an acidolysis solution of phosphorite by decomposing with nitric acid according to claim 1, wherein the humic acid is brown humic acid and/or black humic acid which are insoluble in acid.
3. 3. The method for filtering acidolysis solution of phosphorite by decomposing with nitric acid according to claim 1, wherein the primary filter residue is used for producing organic-inorganic mixed fertilizer.
4. 4. The method for filtering acidolysis solution of phosphorite by decomposing nitric acid according to claim 1, wherein the addition amount of the magnetic carbon filter aid is 5-10% of the weight of the acidolysis solution.
5. 5. The method for filtering acidolysis solution of phosphorite by decomposing nitric acid according to claim 1, wherein the method is characterized in that a frame filter press is adopted for primary filter pressing and secondary filter pressing.
6. 6. The method for filtering acidolysis solution of phosphorite by decomposing nitric acid according to claim 1, wherein the excitation voltage of the plasma ball mill in the step (1) is 5-10KV, the rotating speed is 500-1000r/min, and the grinding time is 1-1.5h.

Description

Filter aid for decomposing phosphate rock acidolysis solution by nitric acid and filtering method Technical Field The invention relates to the field of filter aids, in particular to a filter aid for decomposing phosphate rock acidolysis solution by nitric acid and a filtering method. Background At present, 77% of the yield of phosphorite in China is used for processing and producing phosphate fertilizer. The processing modes of phosphorite can be divided into a thermal method and a wet method. The wet process is to decompose phosphate rock powder with inorganic acid, separate coarse phosphoric acid and purify to obtain phosphoric acid product, and the phosphoric acid product is mainly decomposed with sulfuric acid. However, sulfuric acid decomposes phosphorite to generate a large amount of phosphogypsum, and the phosphogypsum occupies a large amount of land in the piling process, wherein water-soluble fluorine and phosphorus pentoxide contained in the phosphogypsum can be leached out along with rainwater to generate acidic wastewater, so that serious environmental pollution is caused, and precious sulfur resources are wasted. At present, various methods are developed for decomposing phosphorite by nitric acid at home and abroad, and the methods for realizing industrialization at home and abroad mainly comprise a freezing method, a nitric acid-sulfuric acid or sulfate method and a nitric acid-phosphoric acid method according to different treatment modes of calcium resources. The acidolysis solution of the phosphorite by nitric acid contains organic suspended matters and acid insoluble matters, the acid insoluble matters mainly comprise silica sand, non-decomposed mineral matters, insoluble phosphate, insoluble fluoride and magnetic insoluble matters, if the acidolysis solution is not treated, the separation efficiency is extremely low and cannot meet the requirement of industrial production when the acidolysis solution is subjected to solid-liquid separation, the acidolysis solution can be clamped in gypsum in the subsequent decalcification process, the size of dihydrate gypsum crystals can be influenced, the filtering and washing are not facilitated, the nutrient loss is increased, the gypsum is more difficult to reprocess and utilize, and the cyclic economy is not met. In the process for producing high-concentration nitrophosphate fertilizer (application number: 200910009223.3), acid-insoluble substances are settled on acidolysis solution, but fine acid-insoluble substances and organic suspended matters still remain in the acidolysis solution, and the settling method requires longer time and has poor effect. Disclosure of Invention Aiming at the technical problems of poor removal effect and long time of fine acid insoluble matters and organic suspended matters which appear when acidolysis solution generated by decomposing phosphorite with nitric acid is subjected to sedimentation treatment, the invention provides a filter aid for acidolysis solution of decomposing phosphorite with nitric acid and a filtering method. In a first aspect, the invention provides a filter aid for decomposing phosphate rock acidolysis solution by nitric acid, wherein the filter aid is a magnetic carbon filter aid, and the preparation method of the magnetic carbon filter aid comprises the following steps: (1) Fully mixing coal gasification coarse slag and electrolyte solution containing calcium ions according to a solid-to-liquid ratio of 1g:6-8ml, and then adding the mixture into a plasma ball mill for grinding; (2) Transferring the ball-milled product to a tubular reaction furnace, heating to 200-500 ℃ and reacting for 1-3h in a steam atmosphere; (3) Immersing the reaction product obtained in the tubular reaction furnace in the step (2) in alginic acid and amino acid iron solution according to the solid-to-liquid ratio of 1g to 10-20ml, ultrasonically oscillating for 1-3h, and centrifugally separating to obtain a solid product; (4) The solid product is put into a tubular reaction furnace to be heated and dried, the temperature is 300-600 ℃ and the time is 1-2h. Further, in the step (1), the excitation voltage of the ball mill is 5-10KV, the rotating speed is 500-1000r/min, and the grinding time is 1-1.5h. Further, the specific surface area of the magnetic carbon filter aid is 300-500m 2/g, and the pore diameter is 20-100 microns. The invention provides a filtering method for decomposing phosphate rock acidolysis solution by nitric acid, which comprises the steps of carrying out filter pressing on acidolysis solution obtained by decomposing phosphate rock by nitric acid in two steps, firstly adding humic acid into acidolysis solution, stirring until the mixture is uniform, standing and settling, carrying out primary filter pressing to obtain primary filter residues and primary filtrate, then adding the magnetic carbon filter aid into the primary filtrate, stirring until the mixture is uniform, standing and settling, and carrying