Search

CN-121974751-A - Synergistic preparation method of biochar-based micro-mineral organic fertilizer

CN121974751ACN 121974751 ACN121974751 ACN 121974751ACN-121974751-A

Abstract

The invention belongs to the field of agricultural fertilizers and provides a synergistic preparation method of a biochar-based micro-mineral organic fertilizer, wherein carboxyl-phosphate-based functionalized biochar is adopted as a core, a core-shell complex is constructed through in-situ mineralization deposition of micro-mineral ions and phosphate, and the outer layer is enriched in the core-shell complex through gradient coating granulation, so that the three-stage synergistic design is realized, the compressive strength of particles is more than 30N, the pulverization rate is less than 5%, the availability of micro-mineral available nutrients is improved by more than 40%, the contradiction that the existing micro-mineral organic fertilizer is difficult to consider when the high strength and the pulverization of particles are low and the availability of micro-minerals are rapid, the storage stability and the rhizosphere response release are difficult to consider is difficult to consider, and the mineralization of the shell is stable and processable and the element availability is difficult to consider when the release synchronism is maintained is difficult to consider is solved, and the synergistic preparation method has application value for remarkably improving the utilization efficiency of the micro-mineral fertilizer and the growth promoting effect of crops.

Inventors

  • YU WEIJIA
  • LIU KEKE
  • ZHANG ZHENG
  • WEI XIANGSHENG

Assignees

  • 山东爱福地生物股份有限公司

Dates

Publication Date
20260505
Application Date
20260211

Claims (10)

  1. 1. The synergistic preparation method of the biochar-based micro-mineral organic fertilizer is characterized by comprising the following steps of: S1, preparing a carboxyl-phosphate group functionalized biochar intermediate; s2, taking the carboxyl-phosphate group functionalized biochar intermediate as a core, forming a shell layer through in-situ mineralization deposition of micro-mineral ions and phosphate groups, and preparing a biochar@micro-mineral mineralization shell-core-shell composite intermediate, wherein the shell layer is connected with the core through coordination and/or ion interaction between metal ions and carboxyl and/or phosphate groups; S3, mixing and granulating the biochar@micro-mineral mineralized shell-core-shell composite intermediate with decomposed organic materials to obtain biochar-based micro-mineral organic fertilizer particles; The micro-mineral ion source is one or more selected from ferrous sulfate heptahydrate, zinc sulfate heptahydrate and manganese sulfate monohydrate, the phosphate source is one or two selected from sodium dihydrogen phosphate and phosphoric acid, and the biochar@micro-mineral mineralized shell-core-shell composite intermediate is prepared separately and dried into powder or used in a slurry form without drying before the step S3.
  2. 2. The method according to claim 1, wherein the biochar intermediate in step S1 is prepared by: A1, preparing raw materials, namely taking agriculture and forestry plant source waste biomass and adjusting the water content of the biomass to 5wt to 15wt percent; a2, pyrolyzing, namely pyrolyzing 0.5 h to 1.5 h at 450 ℃ to 550 ℃ under the anoxic or micro-aerobic atmosphere to obtain biochar; A3, crushing and screening, namely crushing and screening the obtained biochar to obtain a biochar intermediate, wherein D50 is 50-500 mu m.
  3. 3. The method of claim 1, wherein the carboxy-phosphate functionalized biochar intermediate is prepared by: B1, oxidizing and introducing carboxyl, namely adding the biochar intermediate into a hydrogen peroxide solution, wherein the concentration of the hydrogen peroxide solution is 3 wt-30 wt percent, the solid-liquid mass ratio is 1 (5-30), and the reaction is carried out at 40-80 ℃ for 0.5 h-2.0 h; b2, washing and neutralizing, namely washing with deionized water and filtering until the pH value of the filtrate is 6.5-7.5; B3, phosphoric acid treatment, namely adding the solid obtained in the step B2 into an aqueous solution of phosphoric acid, wherein the concentration of the aqueous solution of phosphoric acid is 5 wt-30 wt%, and the aqueous solution of phosphoric acid is reacted at 40-80 ℃ for 0.5 h-4.0 h; B4, stopping and post-treating, namely adjusting the pH of the filtrate to be 6.5-7.5 by using a sodium hydroxide aqueous solution or a hydrochloric acid aqueous solution in the washing process, and drying the filtrate to be 4 h-24 h at 60-105 ℃ to obtain the carboxyl-phosphate functionalized biochar intermediate.
  4. 4. The method according to claim 1, wherein the biochar @ micro-mineral mineralized shell core shell composite intermediate in step S2 is prepared by: c1, preparing a micro-mineral solution, namely dissolving the micro-mineral ion source compound into deionized water to obtain a micro-mineral solution with the total metal ion concentration of 0.02 mol/L to 0.50 mol/L; preparing a phosphate radical solution, namely dissolving one or two of sodium dihydrogen phosphate and phosphoric acid into deionized water to obtain a solution with the phosphate radical concentration of 0.02 mol/L to 0.50 mol/L; Adding the carboxyl-phosphate group functionalized biochar intermediate into the micro-mineral solution obtained in the step C1, then adding the phosphate radical solution obtained in the step C2, regulating the pH of the system to 6.5-8.0 by using a sodium hydroxide aqueous solution, and reacting at 25-60 ℃ to 0.5 h-2.0 h to form a mineralized shell layer; c4, post-treatment, namely filtering and washing with deionized water until the pH value of the filtrate is 6.5 to 7.5, and drying 4h to 24 h at 60 to 90 ℃ to obtain the biochar@micro-mineral mineralized shell-core-shell composite intermediate; Wherein the thickness of the mineralized shell layer is 5 nm-50 nm, and the total load of the micro-ores of the bio-carbon@micro-ore mineralized shell-core-shell composite intermediate is 0.5-wt% to 8-wt%.
  5. 5. The method according to claim 1, wherein the granulating of step S3 comprises a gradient coated granulating step: D1, inner core granulation, namely mixing the decomposed organic material with the biochar@micro-ore mineralized shell-core-shell composite intermediate obtained in the step S2 according to 30-70% of the total usage amount of the biochar@micro-ore mineralized shell-core-shell composite intermediate used in the step S3, adding sodium alginate as a granulating binder, wherein the adding amount of the sodium alginate is 0.1-3 parts by mass, and the parts by mass are relative parts by mass, so that the water content of the mixture is 15-wt% and 35-wt%, and granulating to form a particle inner core; D2, coating the outer layer, namely, carrying out secondary coating on the inner cores of the particles, adding all the rest biochar@micro-ore mineralized shell-core-shell composite intermediate, and coating the rest biochar@micro-ore mineralized shell-core-shell composite intermediate on the outer layers of the particles by virtue of the granulating binder to obtain gradient particles of the outer layer enriched biochar@micro-ore mineralized shell-core-shell composite intermediate; D3, drying, namely drying at 40-60 ℃ to obtain the finished product with the water content of 5 wt-15 wt percent, wherein the temperature is 0.5 h-4.0 h.
  6. 6. The method according to claim 1, characterized in that one or more of the following technical characteristics are fulfilled: a) The micro-mineral ions comprise Fe ions, zn ions and Mn ions, and the molar ratio of Fe to Zn to Mn is1 (0.1 to 2.0): (0.1 to 2.0); b) The molar ratio of the micro-mineral ions to the phosphate radicals in the step S2 is 0.5 to 2.0:1, wherein the molar ratio is the ratio of the total mole number of the metal ions to the total mole number of the phosphate radicals; c) In the step S3, kaolin is further added as anti-caking mineral powder, wherein the addition amount of the kaolin is 0 to 5 parts by mass, and the parts by mass are relative parts by mass; d) The water content of the biochar@micro-mineral mineralized shell-core-shell composite intermediate after being dried before being added into the step S3 is 0.5 wt-10 wt%.
  7. 7. A biochar-based micro-mineral organic fertilizer granule, characterized in that the granule product prepared by the method of any one of claims 1 to 6 is a relative mass part of each component in terms of mass parts, comprising the following: 50 to 85 parts by mass of decomposed organic materials; 5 to 20 parts by mass of a biochar@micro-mineral mineralized shell-core-shell composite intermediate; Sodium alginate 0.1-3 parts by mass; And 0 to 5 parts by mass of kaolin.
  8. 8. The biochar-based micro mineral organic fertilizer granule according to claim 7, wherein the granule has a particle size of 2 mm to 6 mm and a water content of 5wt% to 15 wt%.
  9. 9. The biochar-based micro-mineral organic fertilizer granule according to claim 7, wherein the thickness of the mineralized shell layer of the biochar @ micro-mineral mineralized shell-core-shell composite intermediate is 5 nm to 50 nm, the total micro-mineral loading amount of the biochar @ micro-mineral mineralized shell-core-shell composite intermediate is 0.5 to wt% to 8 wt%, and the granule has a gradient structure of the outer layer enriched biochar @ micro-mineral mineralized shell-core-shell composite intermediate, and the thickness of the outer layer is 50 to 500 μm.
  10. 10. The biochar-based micro-mineral organic fertilizer granule of claim 7, wherein the micro-mineral ion source used in the preparation process of the granule comprises ferrous sulfate heptahydrate and zinc sulfate heptahydrate or ferrous sulfate heptahydrate and manganese sulfate monohydrate, and the decomposed organic material is livestock manure decomposed substance, straw decomposed substance or a combination thereof.

Description

Synergistic preparation method of biochar-based micro-mineral organic fertilizer Technical Field The invention relates to the technical field of agricultural fertilizers, in particular to a synergistic preparation method of a biochar-based micro-mineral organic fertilizer. Background In modern agricultural production, microelement nutrition plays an irreplaceable important role in crop growth and development and quality formation, and iron, zinc, manganese and other microelement elements not only participate in photosynthesis, respiratory metabolism and enzyme system regulation of plants, but also directly influence stress resistance, yield and nutritional quality of crops. With popularization of high-yield crop varieties and popularization of intensive planting modes, the problem of lack of soil trace elements is increasingly remarkable, and especially in alkaline soil, calcareous soil and long-term high-strength planting areas, the bioavailability of iron-zinc-manganese and other trace mineral elements is remarkably reduced, so that crop element deficiency symptoms frequently occur, and yield and quality are reduced. Therefore, the development of the efficient micro-mineral fertilizer product improves the bioavailability and the utilization efficiency of the trace elements in the soil-plant system, and has important significance for guaranteeing the grain safety, improving the quality of agricultural products and promoting the sustainable development of agriculture. Meanwhile, with the rapid development of organic agriculture and green agriculture, consumers and producers put forward higher requirements on environmental friendliness, long-acting property and intelligent responsiveness of fertilizer products, and scientific compounding and collaborative optimization of micro-mineral nutrition, organic materials and functional carriers are urgently needed, so that the dual aims of high-efficiency utilization of nutrients and environmental protection are realized. Aiming at the research and development of the micro-mineral organic fertilizer, a great deal of research and development are carried out at home and abroad at present, for example, chinese patent publication No. CN1083461A discloses a composite trace element liquid fertilizer which takes low-molecular-weight fulvic acid as a trace element carrier, but has the defects of easy fixation of micro-mineral ions in alkaline soil, quick loss of available nutrients and high transportation crushing and pulverization rate caused by insufficient mechanical strength of particles, for example, chinese patent publication No. CN111517875A discloses a medium trace element slow-release fertilizer for tobacco, a preparation method and application thereof, and the micro-mineral salt solution is loaded into biochar pores by adopting an impregnation adsorption method, but has the defects of limited loading capacity, easy desorption and leaching of the micro-mineral ions, easy moisture absorption and agglomeration during storage period and insufficient release response after the micro-mineral ions are applied to soil. The method mainly aims at solving the contradiction of the mechanism level that the binder dosage is usually required to be increased or the granulating pressure is usually required to be increased to improve the granule strength and reduce the pulverization rate, but the bioavailability is reduced by wrapping and passivating the active ingredients of the micro-minerals, the water content of the product is required to be controlled and the granule compactness is enhanced to ensure the storage stability, the quick disintegration and nutrient release capacity in the rhizosphere wet environment after the fertilizer is applied to soil is weakened, the chemical morphology and release dynamics of different elements in the multi-element micro-mineral fertilizer are obviously different, the dissolution-adsorption-conversion behaviors of the ferrum-zinc-manganese in the soil are asynchronous, and the synergistic efficient supply of the crop growth critical period is difficult to realize. Therefore, the technical bottleneck of the prior art is broken through from the cooperative aspect of material structural design and preparation process, and a novel micro-mineral organic fertilizer product with high mechanical strength, high micro-mineral effectiveness, intelligent response release and multi-element synchronous supply capability is developed. Disclosure of Invention The invention aims to provide a synergistic preparation method of a biochar-based micro-mineral organic fertilizer, which solves the problems that the existing micro-mineral organic fertilizer is difficult to be compatible with high-strength low-pulverization of particles and high-availability quick bioavailability of micro-minerals, the storage period is difficult to be compatible with moisture absorption and agglomeration resistance and rhizosphere wet state response release after soil application, an