Biomass ash, method for preparing the same, and use thereof

Abstract

This invention belongs to the field of aquaculture technology, specifically relating to a biomass ash, its preparation method, and its application. The biomass ash is the ash obtained after burning biomass raw materials, containing phosphate ions, potassium ions, copper ions, manganese ions, iron ions, zinc ions, magnesium ions, and calcium ions. The preparation method of the biomass ash includes air-drying, pulverizing, and granulating the biomass raw materials, then burning them at 600–800 °C for 60–120 minutes under oxygen-supplied conditions, followed by sieving to obtain the biomass ash. This biomass ash is placed in permeable bags and suspended in the water body for giant freshwater prawn farming to achieve slow ion release; it can also be used in conjunction with quicklime during the pond drying stage to establish a two-stage mineralization system. This invention can achieve a comprehensive, continuous, and stable replenishment of multiple ions in the water body, effectively improving the molting success rate of giant freshwater prawns and realizing the resource utilization of waste.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, specifically relating to a biomass ash, its preparation method and application, and particularly to an ion regulation method for the culture water of giant freshwater prawns based on biomass ash. Background Technology

[0002] In the farming of giant freshwater prawns, the deficiency of trace elements and the imbalance of ion ratios in the water can lead to problems such as difficulty in molting and an increase in the proportion of soft-shelled prawns. Therefore, ion regulation of the farming water is beneficial to the healthy growth of giant freshwater prawns.

[0003] The main inorganic components of the shell of the giant freshwater prawn include calcium ions (Ca). 2+ ), magnesium ions (Mg 2+ ) and phosphate ions (PO4) 3 Of the minerals in shrimp shells, calcium ions are the most abundant, primarily existing as calcium carbonate (CaCO3) and calcium phosphate (Ca3(PO4)2), and are the main contributor to shell hardness. Magnesium ions are second only to calcium, usually existing as magnesium carbonate (MgCO3), and affect the toughness and elasticity of the shell. Phosphate ions mainly combine with calcium to form calcium phosphate salts, an important inorganic component of shrimp shells. In addition, potassium ions (K... + Although potassium does not directly form the shrimp shell, it participates in muscle contraction and nerve conduction. Potassium deficiency can cause shrimp to become weak and unable to molt successfully, leading to molting failure and eventual death. Potassium also helps maintain the balance of osmotic pressure inside and outside the body; potassium deficiency can lead to fluid loss and weakened shrimp. Furthermore, potassium participates in energy metabolism and affects the activity of ATPase; a lack of potassium ions can cause crustaceans to have poor appetite, low food conversion efficiency, and stunted growth.

[0004] Currently, common industry practices for ion regulation in aquaculture water include: simply applying quicklime (CaO) to supplement calcium; supplementing with potassium and magnesium salts (such as KCl, MgCl2) or potassium and phosphate salts (KH2PO4); or using expensive commercial mineral preparations. These methods typically supplement only one or a few ions, neglecting the need for calcium. 2+ Mg 2+ K + PO4 3 The synergistic effects of various key ions in the mineralization and molting processes of crustaceans make it difficult to achieve comprehensive and effective regulation of the ion balance in water bodies. Summary of the Invention

[0005] In view of this, one of the objectives of the present invention is to provide a biomass ash to solve the technical problem that the existing technology, which only supplements ions by simply sprinkling quicklime, potassium magnesium salts, etc., is difficult to achieve comprehensive regulation of the ion balance of water bodies.

[0006] The second objective of this invention is to provide a method for preparing biomass ash, so as to solve the technical problem of the ineffective resource utilization of agricultural biomass waste.

[0007] The third objective of this invention is to provide an application of biomass ash in regulating water ions, particularly for the aquaculture water of giant freshwater prawns. The aim is to achieve a continuous and stable replenishment of various ions in the water, avoiding the drastic fluctuations in ion concentration caused by traditional one-time spraying methods, and further solving the problems of low molting success rate and high incidence of soft shells in giant freshwater prawns.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: The present invention first provides a biomass ash, which is the ash obtained after burning biomass raw materials.

[0009] Biomass ash has a wide range of raw material sources, low cost, and contains a variety of mineral elements that are beneficial to aquaculture.

[0010] Preferably, the biomass raw material includes at least one of rice straw, corn stalks, rice husks, and sawdust.

[0011] The above-mentioned raw materials are all common agricultural or forestry wastes. By utilizing them as resources, not only can waste be turned into treasure, but the environmental pressure caused by waste accumulation can also be reduced, resulting in good ecological benefits. Biomass ash from different raw material sources varies in ionic composition. Single or mixed raw materials can be selected for preparation according to actual aquaculture needs to achieve flexible control of ionic composition.

[0012] Preferably, the ash contains at least one of phosphate ions, potassium ions, copper ions, manganese ions, iron ions, zinc ions, magnesium ions, and calcium ions.

[0013] These ions are essential elements for the growth, molting, and mineralization processes of crustaceans. Calcium ions are the main source of shell hardness in shrimp, magnesium ions affect shell toughness and elasticity, phosphate ions participate in the formation of inorganic salt structures in the shell, and potassium ions play a role in muscle contraction, osmotic pressure regulation, and energy metabolism. Trace elements such as copper, manganese, iron, and zinc are also essential for maintaining normal physiological functions in aquatic animals. Therefore, the biomass ash provided by this invention can comprehensively supplement multiple nutrients and trace elements, solving the technical problem of existing technologies that only supplement single or a few ions, making it difficult to achieve comprehensive regulation of ion balance in water bodies. This meets the diverse ion needs of the giant freshwater prawn during molting and growth.

[0014] Preferably, the biomass ash is prepared using an oxygen-supply combustion process.

[0015] Oxygen-supplied combustion ensures that biomass feedstocks are fully combusted, converting organic matter completely into carbon dioxide and water, while the mineral elements are stably retained in the ash as oxides or salts.

[0016] This invention also provides a method for preparing biomass ash, comprising the following steps: S1. Naturally air-dry the biomass raw materials, control the moisture content of the raw materials, crush them, and make biomass pellet fuel; S2. Place the biomass pellet fuel in a combustion device and, under oxygen supply conditions, allow it to burn completely; S3. After combustion, wait for the furnace temperature to cool to room temperature, collect the residual ash at the bottom of the furnace, and pass it through a standard sieve to obtain the biomass ash.

[0017] In S1, controlling the moisture content improves the efficiency and stability of subsequent combustion, preventing incomplete combustion due to excessive moisture. Crushing and granulation homogenize the raw materials, facilitating uniform feeding and complete combustion in the combustion equipment.

[0018] Preferably, the moisture content of the raw material is ≤10%.

[0019] Preferably, the particle size is 2-5 mm.

[0020] Preferably, the biomass pellet fuel has a diameter of 6 to 8 mm.

[0021] Controlling the moisture content to below 10% can effectively reduce energy loss during combustion; a particle size of 2–5 mm is beneficial for the density of the pellets during pellet formation; and a particle diameter of 6–8 mm has good combustion stability and versatility.

[0022] In S2, oxygen-supplying combustion is a key step to ensure that biomass feedstock is completely converted into ash, which can retain the mineral elements in the feedstock and convert them into stable soluble or slow-soluble forms.

[0023] Preferably, the oxygen supply method is forced ventilation, the oxygen supply substance is air, and the flow rate is 2~5 L / min.

[0024] Preferably, the combustion temperature is 600–800 °C.

[0025] Preferably, the combustion time is 60 to 120 minutes.

[0026] Forced air supply ensures sufficient oxygen in the furnace, allowing for full contact between fuel and oxygen and achieving complete combustion. Too low a temperature leads to incomplete combustion and excessive organic matter residue; too high a temperature may cause some mineral elements to volatilize or sinter. A combustion temperature of 600–800 °C is the optimal range for balancing combustion efficiency and ash quality. A combustion time of 60–120 minutes ensures that biomass feedstocks of different densities and calorific values ​​achieve complete combustion, guaranteeing the stability of ash yield and composition.

[0027] Since different biomass raw materials have different ash composition, bulk density and calorific value, their optimal combustion temperature and time are also slightly different. The combustion process parameters are shown in Table 1.

[0028] Table 1 shows the combustion process parameters for different raw materials. Note: Ash yield = Ash mass / Raw material dry weight × 100%, and all parameters are the mean ± standard deviation of three repeated experiments.

[0029] Table 1 shows the combustion process parameters for different raw materials. As can be seen from Table 1, rice husks, being rich in SiO2, have a significantly higher ash yield than other raw materials; sawdust has a high organic matter content and the lowest ash yield.

[0030] Preferably, the standard sieve is a 100-mesh sieve.

[0031] A 100-mesh sieve can effectively screen out large particles of unburned char ash while ensuring that the ash passing through the sieve has a suitable particle size distribution.

[0032] The present invention further provides an application of biomass ash in regulating ions in water.

[0033] Preferably, the water body is a culture water body for giant freshwater prawns.

[0034] Giant freshwater prawns have a high demand for calcium, magnesium, potassium, and phosphorus ions in water, and their molting process is extremely sensitive to ion stability. Therefore, the biomass ash provided in this invention is suitable for ion regulation.

[0035] Preferably, the method for using the biomass ash to culture giant freshwater prawns includes the following steps: The biomass ash is placed into a permeable bag, which is then suspended in the water body for raising giant freshwater prawns. This allows the ions in the biomass ash to be slowly released into the water, dissolving and improving the molting success rate and survival rate of giant freshwater prawns, as well as promoting their growth and development.

[0036] As a slow-release carrier, the permeable bag's physical barrier function can effectively control the surface area and contact time between biomass ash and water, allowing ions in the ash to dissolve slowly at a relatively stable rate. This avoids the instantaneous concentration peaks and impacts on aquaculture organisms caused by traditional one-time spraying methods, and significantly extends the effective time of ion replenishment.

[0037] Preferably, quicklime is applied to the water body for raising giant freshwater prawns, and the biomass ash is placed in a permeable bag. The permeable bag is then suspended in the water body for raising giant freshwater prawns, so that the ions in the biomass ash are slowly released into the water body and dissolved. Through the synergistic effect of quicklime and biomass ash, the molting success rate and survival rate of giant freshwater prawns are improved, as well as the growth and development of giant freshwater prawns are promoted.

[0038] Preferably, green algae grow naturally in the water body where the giant freshwater prawns are cultured.

[0039] Preferably, the green algae includes at least one of Chlorella spp., Scenedesmus spp., and Oocystis spp.

[0040] Biomass ash contains Mg 2+ and PO4 3- Mg 2+ Phosphorus is the central metal atom in chlorophyll molecules, capable of absorbing light energy and converting it into chemical energy to drive photosynthesis; phosphorus content is typically a key nutrient element for algal growth. Mg 2+ and PO4 3- It helps promote the growth of green algae, and the growth of green algae is beneficial to water quality (NH4+). + NO2 - NO3 - It has a significant effect on improving dissolved oxygen, thereby promoting the growth and development of giant freshwater prawns.

[0041] Preferably, the method for using the biomass ash to farm giant freshwater prawns further includes the following steps: During the pond drying stage before giant freshwater prawn farming, quicklime and biomass ash are applied to the pond to establish a basic mineralized environment for the pond bottom mud and water. During the cultivation of giant freshwater prawns, permeable bags filled with biomass ash are suspended. The synergistic effect of quicklime and bioash can improve the molting success rate and survival rate of giant freshwater prawns, as well as promote their growth and development.

[0042] During the dry pond stage, the application of quicklime and biomass ash ensures sufficient calcium and magnesium ions are stored in the bottom sediment. After water is injected, these ions are slowly released into the water, providing a stable supply of ions for the early stages of giant freshwater prawn (Macrobrachium rosenbergii) farming and avoiding the limited release of biomass ash from the initial hanging bags. During the prawn farming stage, biomass ash is then dynamically replenished through the slow release from the hanging permeable bags, thus maintaining the continuity and stability of water mineralization conditions throughout the entire farming cycle.

[0043] Preferably, during the cultivation of giant freshwater prawns, the method further includes: periodically replacing the biomass ash in the permeable bag according to the cultivation cycle. As the soaking time increases, the ion release rate of the biomass ash in the permeable bag will gradually decrease. Periodic replacement can ensure that a stable ion replenishment rate is maintained throughout the entire cultivation cycle, avoiding a decrease in ion concentration due to the depletion of the ash source.

[0044] The beneficial effects of this invention are: This invention provides a biomass ash, which is made from biomass waste. The ash obtained after combustion contains a variety of ions that are beneficial to the growth and molting of giant freshwater prawns. It can comprehensively supplement multiple ions in water and comprehensively regulate the ion balance in water, solving the problem that existing technologies only supplement a single or a few types of ions, making it difficult to regulate the ion balance in water.

[0045] This invention provides a method for preparing biomass ash. By controlling the moisture content of the raw materials, the particle size of the crushed material, the specifications of the pellet fuel, and the oxygen supply conditions, combustion temperature, and combustion time during the combustion process, this method ensures that the biomass ash has a stable yield, uniform composition, and suitable ionic form, which is beneficial for its subsequent slow-release application in water bodies.

[0046] This invention applies biomass ash to water ion regulation, particularly in the culture water of giant freshwater prawns. By suspending permeable bags, ions are slowly released, effectively avoiding the drastic fluctuations in ion concentration caused by traditional one-time spraying methods. This extends the effective time of ion replenishment, providing a stable and suitable growth environment for giant freshwater prawns, which is conducive to improving their molting success rate and survival rate, and promoting their growth and development. Attached Figure Description

[0047] Figure 1 This is a flowchart of a two-stage mineralization system consisting of pond drying and aquaculture periods. Detailed Implementation

[0048] The following description, with reference to preferred embodiments, illustrates the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are merely illustrative of the present invention and not intended to limit the scope of protection of the present invention.

[0049] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following will provide a more detailed description of a biomass ash, its preparation method, and its application, in conjunction with specific embodiments and accompanying drawings. Obviously, the specific embodiments described are merely some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. Based on the specific embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0050] Where specific techniques or conditions are not specified in the detailed embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. Example 1

[0051] A method for preparing biomass ash includes the following steps: S1. Select rice straw as raw material and air-dry it naturally until its moisture content is controlled at 5%. Then, use a pulverizer to pulverize the air-dried rice straw into particles with a diameter of approximately 3 mm. Finally, process the pulverized rice straw into biomass pellet fuel with a diameter of 7 mm using a biomass pellet mill. S2. The prepared biomass pellet fuel is placed in a combustion furnace for combustion at a temperature of 625 ℃ for 90 minutes. During the combustion process, sufficient oxygen supply is maintained by forced air supply at a flow rate of 3 L / min. S3. After combustion, allow the furnace temperature to cool naturally to room temperature (about 25 ℃), collect the ash residue at the bottom of the furnace, and sieve the collected ash through a 100-mesh standard sieve to remove any unburned large particles of carbon slag and other impurities. The sieved ash is then stored in a permeable bag to obtain a biomass ash prepared from rice straw.

[0052] The ash yield of the biomass ash prepared in this embodiment is approximately 6.2%. Example 2

[0053] A method for preparing biomass ash includes the following steps: S1. Select corn stalks as raw material and air-dry them naturally until their moisture content is controlled at 5%. Then, use a pulverizer to pulverize the air-dried corn stalks into particles with a diameter of approximately 3 mm. Finally, process the pulverized corn stalks into biomass pellet fuel with a diameter of 7 mm using a biomass pellet mill. S2. The prepared biomass pellet fuel is placed in a combustion furnace for combustion at a temperature of 650 ℃ for 90 minutes. During the combustion process, sufficient oxygen supply is maintained by forced air supply at a flow rate of 3 L / min. S3. After combustion, allow the furnace temperature to cool naturally to room temperature (about 25 ℃), collect the ash residue at the bottom of the furnace, and sieve the collected ash through a 100-mesh standard sieve to remove any unburned large particles of carbon slag and other impurities. The sieved ash is then stored in a permeable bag to obtain a biomass ash prepared from corn stalks.

[0054] The ash yield of the biomass ash prepared in this embodiment is approximately 5.4%. Example 3

[0055] A method for preparing biomass ash includes the following steps: S1. Select rice husks as raw material and air-dry them naturally until their moisture content is controlled at 5%. Then, process the air-dried rice husks into biomass pellet fuel with a diameter of 7 mm using a biomass pellet machine. S2. The prepared biomass pellet fuel is placed in a combustion furnace for combustion at a temperature of 725 ℃ for 120 minutes. During the combustion process, sufficient oxygen supply is maintained by forced air supply at a flow rate of 3 L / min. S3. After combustion, allow the furnace temperature to cool naturally to room temperature (about 25 ℃), collect the ash residue at the bottom of the furnace, and sieve the collected ash through a 100-mesh standard sieve to remove any unburned large particles of carbon slag and other impurities. The sieved ash is then stored in a permeable bag to obtain a biomass ash prepared from rice husks.

[0056] The ash yield of the biomass ash prepared in this embodiment is approximately 16.8%. Example 4

[0057] A method for preparing biomass ash includes the following steps: S1. Select sawdust as raw material and air-dry it naturally until its moisture content is controlled at 5%. Then, use a pulverizer to pulverize the air-dried sawdust into particles with a diameter of approximately 3 mm. Finally, process the pulverized sawdust into biomass pellet fuel with a diameter of 7 mm using a biomass pellet mill. S2. The prepared biomass pellet fuel is placed in a combustion furnace for combustion at a temperature of 700 ℃ for 120 minutes. During the combustion process, sufficient oxygen supply is maintained by forced air supply at a flow rate of 3 L / min. S3. After combustion, allow the furnace temperature to cool naturally to room temperature (about 25 ℃), collect the ash residue at the bottom of the furnace, and sieve the collected ash through a 100-mesh standard sieve to remove any unburned large particles of carbon slag and other impurities. The sieved wood ash is then stored in a permeable bag to obtain a biomass ash prepared from sawdust.

[0058] The ash yield of the biomass ash prepared in this embodiment is approximately 3.1%. Example 5

[0059] A method for farming giant freshwater prawns includes the following steps: There are three processing groups set up: CK group: No exogenous substances were applied; only normal water levels and water exchange management were maintained. The stocking density of shrimp larvae was 1200 shrimp / m³. 2 The breeding cycle is 120 days; quicklime group: per 667 m 2 Apply 100 kg of quicklime (dissolved in water and sprinkled throughout the pond), and manage the rest of the work as in the control group; Quicklime + Example 1 Group: per 667 m 2 Apply 100 kg of quicklime (dissolved in water and sprinkled throughout the pond), and simultaneously pack 15 kg of biomass ash prepared in Example 1 into permeable bags (size: 30 cm × 80 cm), and apply it at a rate of 15 kg per 300 m³. 2 One bag was suspended at a uniform density in the middle layer of the water and replaced every 20 days. Other management procedures were the same as for the control group. Example 6

[0060] A method for two-stage culture of giant freshwater prawns includes the following steps: During the pond drying phase, three treatment groups were set up: Group CK: After drying the pond and preparing the land, no substances were applied. The pond was dried according to the conventional process, and seedlings were released directly after filling it with water. Quicklime group: After drying and preparing the pond, apply 100 kg of quicklime evenly to the entire pond at a rate of 667 m². 2 Plow and mix in the bottom mud, then fill the pond with water after drying for 7 days; Quicklime + Example 1 Group: Based on the quicklime group, 50 kg / 667 m³ of biomass ash prepared in Example 1 was applied in combination. 2 After drying the pond for 7 days, water is added.

[0061] During the breeding stage, three treatment groups were set up as follows: CK group: Normal feeding management, no hanging of biomass ash bags, no additional application of mineral supplements; Quicklime group: Normal feeding and management, quicklime was only added during the pond drying phase; Quicklime + Example 1 Group: Normal feeding management; quicklime and biomass ash were applied during the dry pond stage (mineralization of bottom mud); during the aquaculture stage, permeable bags of biomass ash prepared in Example 1 were suspended (dosage: 15 kg / bag, per 300 m³). 2 (Hang one bag), and replace it regularly every 20 days.

[0062] Detection and Analysis 1) Ionic composition detection of biomass ash The ionic composition of the biomass ash prepared in Examples 1-4 was detected. The specific procedures were as follows: 0.2 g of each biomass ash sample prepared in each example was placed in a polytetrafluoroethylene digestion vessel. 5 mL of nitric acid (HNO3, analytical grade) and 1 mL of hydrochloric acid (HCl, analytical grade) were added. Digestion was performed using a microwave digester (reference power: 800 W, temperature program: increase to 180 °C within 10 min and hold for 20 min). After cooling, the digestate was transferred to a 50 mL volumetric flask, diluted to the mark with ultrapure water, and filtered through a 0.45 μm filter before analysis. P, K, Cu, Mn, Fe, Zn, Mg, and Ca were determined using inductively coupled plasma optical emission spectrometry (ICP-OES, Thermo iCAP 7000 series). Results were expressed as g / kg dry weight. Each sample was measured in triplicate, and the average value was taken.

[0063] Table 2 shows the ionic composition of the biomass ash prepared in Examples 1-4. Table 2 shows the ionic composition of the biomass ash prepared in Examples 1-4. As can be seen from Table 2, the biomass ash prepared from different biomass raw materials contains phosphate ions, potassium ions, copper ions, manganese ions, iron ions, zinc ions, magnesium ions, and calcium ions. This indicates that the biomass ash provided by this invention can comprehensively supplement various nutrients and trace elements, meeting the diverse ionic needs of the giant freshwater prawn during molting and growth.

[0064] 2) Detection of basic physicochemical properties of biomass ash The basic physicochemical properties of the biomass ash prepared in Examples 1-4 were investigated. pH was measured using a calibrated pH meter (accuracy ±0.01) after the 1:10 ash-water suspension (mass-volume ratio) was allowed to stand at 25 °C for 1 h. Conductivity was measured with the same suspension ratio. Locus of Intake (LOI) was measured by calcination at 550 °C for 2 h in a muffle furnace. Specific surface area (BET) was determined using the N2 adsorption method. Moisture content was measured according to GB / T 28731-2012, dried to constant weight in a 105 °C oven, and the percentage of weight loss was calculated. The samples were naturally filled into 100 mL graduated cylinders to the mark, weighed, and the bulk density was calculated. The median particle size (D) was determined using a laser particle size analyzer (wet method, dispersion medium: ultrapure water). 50 The results are shown in Table 3.

[0065] Table 3 shows the basic physicochemical properties of the biomass ash prepared in Examples 1-4. Table 3 shows the basic physicochemical properties of the biomass ash prepared in Examples 1-4. As can be seen from Table 3, the physicochemical properties of biomass ash prepared from different biomass raw materials vary. One or more types of biomass ash can be selected for water ion regulation according to actual water body requirements.

[0066] 3) Water ion stability testing Giant freshwater prawns were cultured using the method described in Example 5. Water ion levels were monitored during the culture period. The specific operational steps were as follows: Sampling: Water samples were collected every 30 days during the aquaculture period. Three fixed sampling points were set up in each experimental pond (both ends and the middle of the pond). Water samples were taken from 50 cm below the water surface and mixed to obtain a representative water sample. The water samples were placed in polyethylene bottles, acidified with 65% nitric acid (analytical grade) to pH < 2, and stored at 4 °C. The analysis was completed within 72 hours.

[0067] Ion detection: Ca 2+ Mg 2+ K + PO4 was detected using inductively coupled plasma optical emission spectrometry (ICP-OES, model: ThermoiCAP 7000 series). 3- The molybdenum blue colorimetric method (GB / T 11893-1989) was used for detection; total alkalinity was determined by hydrochloric acid titration (GB / T 15451-2006); pH was measured in situ during on-site sampling using a portable pH meter (accuracy ±0.01, Mettler Toledo FG2). The instrument was calibrated at three points with standard buffer solutions (pH 4.00, 7.00, 10.01) before use.

[0068] Stability assessment: The coefficient of variation (CV%) = standard deviation / mean × 100% was used as an indicator of ion concentration stability. The smaller the CV, the more stable the ion concentration in the water. The Ca:Mg molar ratio was also calculated as a comprehensive evaluation indicator of the water's mineralization balance.

[0069] The results are shown in Table 4.

[0070] 4) Molting and growth performance detection Giant freshwater prawns were cultured using the method described in Example 5. During the culture period, the molting and growth performance of the prawns were monitored. The specific operational steps were as follows: 1. Soft-shell rate determination: After 120 days of culture, shrimp were randomly caught by net casting, with 50 shrimp randomly captured from each pond. The number of hard-shell shrimp (whose shells were completely mineralized and hardened after molting) and soft-shell shrimp (whose shells were still soft within 4 hours after molting) were counted separately. Soft-shell rate (%) = Number of soft-shell shrimp / Total number of shrimp inspected × 100% 2. Survival rate: At the end of the breeding cycle (120 days) for each group, three samples were taken to count the number of shrimp per kg and calculate the average weight (g) of a single shrimp.

[0071] Average final weight (g) = (N1 + N2 + N3) / 1000 / 3, where N1, N2, and N3 are the number of shrimp sampled from 1 kg in 3 separate samplings. Survival count = Total weight / Average weight per shrimp Survival rate (%) = (Number of surviving shrimp / Initial total number of shrimp) × 100% The results are shown in Table 4.

[0072] Table 4 shows the combined effects of culturing Giant freshwater prawns using the method described in Example 5 on water ion stability, molting performance, and growth indicators. Table 4 shows the comprehensive effects of the culture method of Example 5 on water ion stability, molting performance, and growth indicators of Macrobrachium rosenbergii. As shown in Table 4, compared with the control group and the quicklime group, the application of the bioash and quicklime prepared in Example 1 of this invention resulted in a decrease in Ca2+ concentration in the water. 2+ Mg 2+ and K + The stability of PO4 is improved. 3-The increased content, increased total alkalinity, and significantly decreased Ca:Mg ratio indicate that the biomass ash obtained after combustion contains multiple ions beneficial to the growth and molting of Macrobrachium rosenbergii, enabling comprehensive replenishment of various ions in the water and solving the problem of existing technologies that only supplement a single or a few types of ions. Furthermore, compared to the control group and the quicklime group, the application of the biomass ash and quicklime prepared in Example 1 of this invention significantly reduced the soft-shell rate and significantly increased the survival rate and average final weight. This indicates that the ions provided by the biomass ash provide a stable and suitable growth environment for Macrobrachium rosenbergii, which is beneficial for improving its molting success rate and survival rate, and promoting its growth and development.

[0073] 5) Algal biomass and water quality indicators Giant freshwater prawns were cultured using the method described in Example 5. During the culture period, algal biomass and water quality indicators were measured. The specific operational steps were as follows: Chlorophyll a (µg / L): After collecting water samples, the samples were filtered through a GF / C glass fiber membrane and extracted with 90% acetone at 4 °C in the dark for 24 h. After centrifugation, the supernatant was collected, and the absorbance was measured at 663 nm and 645 nm using a spectrophotometer. The absorbance was calculated according to the Jeffrey & Humphrey formula. Green algae density (cells / mL): Take 1 mL of water sample, fix with Lugol's solution, count the cells using a hemocytometer under an optical microscope (400×), repeat 3 times and take the average value; NH4 + -N, NO2 - -N, NO3 - -N: Determined by Nessler's reagent method (GB / T 7479), N-(1-naphthyl)ethylenediamine spectrophotometry (GB / T 7493) and ultraviolet spectrophotometry (GB / T 7480), respectively; Dissolved oxygen (DO): Measured in situ using a portable dissolved oxygen meter (fluorescence method); Transparency (cm): Measured on-site using the Seidon disk method, taking the average value of the lowering and raising measurements.

[0074] Table 5 shows the effects of culturing giant freshwater prawns using the method described in Example 5 on algal biomass and water quality indicators. Table 5 shows the effects of the culture method of Example 5 on algal biomass and water quality indicators of giant freshwater prawns. As shown in Table 5, compared with the control group and the quicklime group, the application of bioash and quicklime prepared in Example 1 of this invention helps promote the growth of green algae. The growth of green algae is beneficial to water quality (NH4+). + NO2 - NO3 -It has a significant effect on improving dissolved oxygen, thereby promoting the growth and development of giant freshwater prawns.

[0075] 6) Detection of water ion content during both the pond drying and aquaculture periods. Figure 1 This is a flowchart of a two-stage mineralization system involving pond drying and aquaculture. (Example:) Figure 1 As shown, during the pond drying stage before giant freshwater prawn (Macrobrachium rosenbergii) farming, quicklime and biomass ash are applied to the pond to establish a basic mineralized environment in the pond bottom sediment and water. The application of quicklime and biomass ash during the drying stage ensures sufficient calcium and magnesium ions are stored in the bottom sediment. After water is added, these ions are slowly released into the water, providing a stable ion supply for the early stages of farming and avoiding the limited release of ions in the initial stages of biomass ash bag suspension. During the farming stage, the biomass ash is dynamically replenished through the slow release from the suspended biomass ash bags, thus maintaining the continuity and stability of the water's mineralization conditions throughout the entire farming cycle. During giant freshwater prawn farming, the biomass ash in the permeable bags is replaced periodically according to the farming cycle. As the soaking time increases, the ion release rate of the biomass ash in the permeable bags gradually decreases. Regular replacement ensures a stable ion replenishment rate throughout the entire farming cycle, preventing a decrease in ion concentration due to ash depletion.

[0076] Giant freshwater prawns were cultured using the method described in Example 6. Water ion levels were monitored during the culture period. The specific operational steps were as follows: 1. Draining the pond During the pond preparation stage, giant freshwater prawns were cultured according to the method described in Example 6. Water was then injected, and the ion levels in the water were measured 7 days later to assess the effectiveness of establishing the basic mineralization base color. 2+ Mg 2+ K + Detection was performed using inductively coupled plasma optical emission spectrometry (ICP-OES, Thermo iCAP 7000 series); PO4 3- The molybdenum blue colorimetric method (GB / T11893-1989) was used for detection. pH was measured in situ during sampling using a portable pH meter (accuracy ±0.01, Mettler Toledo FG2). The instrument was calibrated at three points with standard buffer solutions (pH 4.00, 7.00, and 10.01) before use. The test results are the mean ± standard deviation of three replicate ponds, and the results are shown in Table 6.

[0077] Table 6 shows the water ion content during the draining stage of giant freshwater prawns cultured using the culture method of Example 6. 2. Dynamic changes of water ions during aquaculture Following the above-mentioned pond drying treatment, the culture period begins. Giant freshwater prawns are cultured according to the method described in Example 6. Throughout the entire culture cycle (120 days), the concentration of major ions (Ca) in the water is measured every 30 days. 2+ K + Mg 2+ The concentration of Ca was determined to verify the effect of the two-stage regulation system on maintaining ion stability. 2+ Mg 2+ K + The results were obtained by inductively coupled plasma optical emission spectrometry (ICP-OES, Thermo iCAP 7000 series) and are shown in Table 7.

[0078] Table 7 shows the dynamic changes of major ions in the water body during the aquaculture period. Note: The unit of ion concentration in the table is mg / L. CV = standard deviation / mean of concentration at each time point × 100%.

[0079] Analysis of Tables 6 and 7 shows that the biomass ash obtained in Example 1 of this invention maintains Ca2+ in the two-stage system. 2 + K + Mg 2+ The concentration remained stable, and the CV value was significantly lower than that of the control group (p < 0.05).

[0080] In summary, the biomass ash of this invention contains various ions beneficial to the growth and molting of *Macrobrachium rosenbergii*, enabling comprehensive replenishment of multiple ions in the water. The slow release of ions via a permeable bag suspension method prolongs the effective replenishment time, providing a stable and suitable growth environment for *Macrobrachium rosenbergii*, thus improving its molting success rate and survival rate, and promoting its growth and development. The dual-stage regulation system maintains the continuity and stability of water mineralization conditions throughout the entire aquaculture cycle, effectively improving the molting environment of *Macrobrachium rosenbergii* and enhancing the stability of aquaculture production.

[0081] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A biomass ash characterized in that, The biomass ash is the ash obtained after burning biomass raw materials.

2. The biomass ash according to claim 1, wherein, The biomass raw materials include at least one of rice straw, corn stalks, rice husks, and sawdust; And / or, the ash contains at least one of phosphate ions, potassium ions, copper ions, manganese ions, iron ions, zinc ions, magnesium ions, and calcium ions.

3. The biomass ash according to any one of claims 1-2, wherein, The biomass ash is prepared using an oxygen-supply combustion process.

4. A method for producing the biomass ash according to any one of claims 1 to 3, characterized by, Includes the following steps: S1. Naturally air-dry the biomass raw materials, control the moisture content of the raw materials, crush them, and make biomass pellet fuel; S2. Place the biomass pellet fuel in a combustion device and, under oxygen supply conditions, allow it to burn completely; S3. After combustion, wait for the furnace temperature to cool to room temperature, collect the residual ash at the bottom of the furnace, and pass it through a standard sieve to obtain the biomass ash.

5. The preparation method according to claim 4, characterized in that, The moisture content of the raw material is ≤10%; And / or, the pulverization to a particle size of 2-5 mm; And / or, the biomass pellet fuel has a diameter of 6 to 8 mm; And / or, the oxygen supply method is forced ventilation, the oxygen supply substance is air, and the flow rate is 2~5 L / min; And / or, the combustion temperature is 600–800 °C; And / or, the combustion time is 60 to 120 minutes; And / or, the standard sieve is a 100-mesh sieve.

6. The application of biomass ash as described in any one of claims 1-3 or biomass ash prepared by the preparation method described in any one of claims 4-5 in regulating ions in water.

7. Use according to claim 6, characterized in that, The water body in question is the water body used for aquaculture of giant freshwater prawns.

8. Use according to claim 7, characterized in that, The method for using biomass ash to culture giant freshwater prawns includes the following steps: The biomass ash is placed into a permeable bag, which is then suspended in the water body for raising giant freshwater prawns. This allows the ions in the biomass ash to be slowly released into the water, dissolving and improving the molting success rate and survival rate of giant freshwater prawns, as well as promoting their growth and development.

9. Use according to claim 8, characterized in that, The method for using biomass ash to culture giant freshwater prawns includes the following steps: Quicklime is applied to the water body for raising giant freshwater prawns, and the biomass ash is placed in a permeable bag. The permeable bag is then suspended in the water body for raising giant freshwater prawns, so that the ions in the biomass ash are slowly released into the water body and dissolved. Through the synergistic effect of quicklime and biomass ash, the molting success rate and survival rate of giant freshwater prawns are improved, as well as the growth and development of giant freshwater prawns are promoted. And / or, green algae naturally grow in the water body where the giant freshwater prawns are farmed; The green algae include at least one of Chlorella spp., Scenedesmus spp., and Oocystis spp.

10. Use according to claim 7, characterized in that, The method for using biomass ash to culture giant freshwater prawns includes the following steps: During the pond drying stage before giant freshwater prawn farming, quicklime and biomass ash are applied to the pond to establish a basic mineralized environment for the pond bottom mud and water. During the cultivation of giant freshwater prawns, permeable bags filled with biomass ash are suspended. The synergistic effect of quicklime and bioash can improve the molting success rate and survival rate of giant freshwater prawns, as well as promote their growth and development.

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