Method for co-processing solid waste gypsum and by-product ammonium chloride
By synergistically processing by-product ammonium chloride and solid waste gypsum, high-purity ammonium carbonate, ammonium sulfate, and nano-calcium carbonate are produced, solving the problems of high energy consumption and high cost in existing technologies, and realizing efficient, low-energy resource utilization and environmental benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Filing Date
- 2026-04-11
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, the resource utilization of ammonium chloride and solid waste gypsum, by-products of the soda ash industry, suffers from high energy consumption, high cost, low product added value, and lacks a fully closed-loop process, making it difficult to achieve large-scale industrial application.
By synergistically treating by-product ammonium chloride with solid waste gypsum, including steps such as crushing, micro-negative pressure and high-negative pressure reaction, ultrafine grinding, and multiphase reaction, high-purity ammonium carbonate, ammonium sulfate, nano-calcium carbonate, and calcium chloride dihydrate are prepared, achieving mutual supply of materials and energy coupling, forming a closed-loop process with low-temperature negative pressure operation throughout the entire process.
It achieves the coordinated disposal of three types of solid waste, reduces raw material costs, produces high value-added products, meets clean production requirements, and has the potential for industrial expansion.
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Figure CN122380422A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of co-resource utilization technology of industrial solid waste, specifically a method for the co-resource utilization and co-production of solid waste gypsum and by-product ammonium chloride. Background Technology
[0002] The production of ammonium chloride, a byproduct of the soda ash industry, is enormous, and long-term stockpiling leads to resource waste and environmental risks. Large quantities of solid waste gypsum such as desulfurization gypsum, phosphogypsum, and titanium gypsum are generated in large quantities, but their comprehensive utilization rate is low. Traditional stockpiling and disposal methods occupy a large amount of land and pose a risk of heavy metal leaching.
[0003] Existing technologies for the resource utilization of by-product ammonium chloride mainly rely on single pyrolysis, which is energy-intensive and produces only a single product. The resource utilization of solid waste gypsum often requires the purchase of ammonium carbonate as a conversion raw material, resulting in high raw material costs and poor economic efficiency. Currently, there is a lack of a fully closed-loop, low-energy-consumption, and zero-emission integrated process that can synergistically utilize by-product ammonium chloride, solid waste gypsum, and calcium-based industrial solid waste, while simultaneously producing high-value-added chemical products. This makes it difficult to meet the needs of large-scale industrial applications. Summary of the Invention
[0004] (a) Technical problems to be solved
[0005] To address the shortcomings of existing technologies, this invention provides a method for the synergistic resource utilization and co-production of solid waste gypsum and by-product ammonium chloride. This method aims to solve the problems of high energy consumption, high cost, low product added value, and lack of closed-loop process in the separate treatment of by-product ammonium chloride and solid waste gypsum. It provides a synergistic resource utilization method with mild reaction conditions, mutual material supply, energy coupling, and no emissions of waste gas, wastewater, and solid waste, thereby achieving the co-production of four products and the synergistic disposal of three types of solid waste.
[0006] (II) Technical Solution
[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for the co-production of solid waste gypsum and by-product ammonium chloride, comprising the following steps:
[0008] Step 1: The by-product ammonium chloride is pulverized and divided into two streams. One stream reacts with calcium carbonate slurry under slight negative pressure in an ultrafine wet mill to prepare an ammonia-carbon dioxide mixture, which is then carbonized to obtain an ammonium bicarbonate solution. The other stream reacts with calcium oxide under high negative pressure in an ultrafine dry mill to prepare high-purity ammonia and solid calcium chloride. The ammonium bicarbonate solution and ammonia are then combined to obtain high-purity ammonium carbonate. The calcium chloride produced by the wet and dry processes is combined and concentrated to prepare calcium chloride dihydrate.
[0009] Step 2: After being crushed, impurities removed, and pulped, the solid waste gypsum is sequentially fed into a high-gravity ammoniation reactor and a multiphase reactor, where it reacts with the high-purity ammonium carbonate prepared in Step 1 at 50°C for 45 minutes. After aging and separation by closed-loop membrane pressure filtration, the gypsum is further processed.
[0010] Step 3: The ammonium sulfate filtrate obtained by separation is evaporated, concentrated, crystallized and dried to obtain the ammonium sulfate product. The calcium carbonate filter cake is dried and ultra-finely ground to obtain the nano calcium carbonate product.
[0011] Preferably, in step one, the ammonium chloride is pulverized to 40-60 mesh, the wet reaction temperature is 60-65℃, and the gauge pressure is -3 to -3.5 kPa; the dry reaction gauge pressure is -80 to -85 kPa; and the synthesis temperature of the high-purity ammonium carbonate is 45-50℃.
[0012] Preferably, in step two, the solid waste gypsum includes one or more of desulfurized gypsum, phosphogypsum, and titanium gypsum.
[0013] Preferably, in step two, the reaction temperature of the multiphase reactor is 50°C, the reaction time is 45 min, and a closed diaphragm filter press is used for separation.
[0014] Preferably, in step one, the calcium carbonate and calcium oxide are one or more of steel slag, Pidgeon process magnesium slag, and ammonia-soda process white mud.
[0015] The present invention also provides a dedicated device for implementing the above method, comprising: an ammonium chloride pulverizing unit, an ultrafine wet mill, an ultrafine dry mill, an ammonium carbonate synthesis unit, a calcium chloride concentration and crystallization unit, a gypsum pretreatment unit, a high-gravity ammoniation reactor, a multiphase reactor, an aging tank, a closed diaphragm filter press, an ammonium sulfate evaporation and crystallization unit, and a nano-calcium carbonate drying and grinding unit; the outlet of the ammonium carbonate synthesis unit is connected to the multiphase reactor, realizing seamless coupling of the two processes.
[0016] Secondly, the reaction principle
[0017] Unit 1: Preparation of Ammonium Carbonate and Calcium Chloride from Ammonium Chloride Byproducts
[0018] 2NH4Cl + CaCO3 = CaCl2 + 2NH3↑ + CO2↑ + H2O
[0019] NH3 + CO2 + H2O = NH4HCO3
[0020] 2NH4Cl + CaO = CaCl2 + 2NH3↑ + H2O
[0021] NH4HCO3 + NH3 = (NH4)2CO3
[0022] Unit 2: Reaction of Ammonium Carbonate with Solid Waste Gypsum
[0023] (NH4)2CO3 + CaSO4 = (NH4)2SO4 + CaCO3↓.
[0024] (III) Beneficial Effects
[0025] This invention provides a method for the co-production of solid waste gypsum and by-product ammonium chloride, which has the following beneficial effects:
[0026] 1. Triple solid waste co-processing: Simultaneously realizes the resource utilization of by-product ammonium chloride, solid waste gypsum, and calcium-based industrial solid waste, with a large amount of solid waste disposal and significant environmental benefits.
[0027] 2. Self-produced and self-supplied ammonium carbonate: No need to purchase ammonium carbonate from outside, significantly reducing raw material costs and improving economic efficiency.
[0028] 3. Mild reaction conditions: The entire process operates at low temperature and negative pressure, without high-temperature calcination, resulting in low energy consumption and high safety.
[0029] 4. Four high-value-added products: co-production of ammonium carbonate, ammonium sulfate, nano calcium carbonate, and calcium chloride, with an excellent product structure and high economic benefits.
[0030] 5. Closed-loop circulation throughout the entire process: No waste gas, no wastewater, and no waste residue are discharged, meeting the requirements of clean production.
[0031] 6. Highly integrated processes: One set of equipment completes the coupling of two industrial chains, saving investment, ensuring continuous and controllable processes, and facilitating industrial scaling. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the process flow of the present invention. Detailed Implementation
[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0034] Example 1:
[0035] like Figure 1 As shown in the figure, this invention provides a method for the co-production of solid waste gypsum and by-product ammonium chloride, comprising the following steps:
[0036] Step 1: The by-product ammonium chloride is pulverized into two streams, with the ammonium chloride being pulverized to 40 mesh. One stream reacts with calcium carbonate slurry in an ultrafine wet mill under slight negative pressure to prepare an ammonia-carbon dioxide mixture. The wet reaction temperature is 60℃, and the gauge pressure is -3kPa, resulting in an ammonium bicarbonate solution. The other stream reacts with calcium oxide in an ultrafine dry mill under high negative pressure to prepare high-purity ammonia and solid calcium chloride. The gauge pressure of the dry reaction is -80kPa. The ammonium bicarbonate solution and ammonia are then combined to synthesize high-purity ammonium carbonate at a temperature of 45℃. The calcium chloride produced by the wet and dry processes is combined and concentrated to prepare calcium chloride dihydrate. The calcium carbonate and calcium oxide are obtained from steel slag and Pidgeon process magnesium slag.
[0037] Step 2: Solid waste gypsum (including desulfurized gypsum and phosphogypsum) is crushed, impurities removed, and pulped, and then sequentially fed into a high-gravity ammoniation reactor and a multiphase reactor. The reaction temperature of the multiphase reactor is 50℃ and the reaction time is 45min. It reacts with the high-purity ammonium carbonate prepared in Step 1 at 50℃ for 45min. After aging and separation by closed-loop diaphragm filter press, the separation is carried out using a closed-loop diaphragm filter press.
[0038] Step 3: The ammonium sulfate filtrate obtained by separation is evaporated, concentrated, crystallized and dried to obtain the ammonium sulfate product. The calcium carbonate filter cake is dried and ultra-finely ground to obtain the nano calcium carbonate product.
[0039] Secondly, the reaction principle of the above method is as follows:
[0040] Unit 1: Preparation of Ammonium Carbonate and Calcium Chloride from Ammonium Chloride Byproducts
[0041] 2NH4Cl + CaCO3 = CaCl2 + 2NH3↑ + CO2↑ + H2O
[0042] NH3 + CO2 + H2O = NH4HCO3
[0043] 2NH4Cl + CaO = CaCl2 + 2NH3↑ + H2O
[0044] NH4HCO3 + NH3 = (NH4)2CO3
[0045] Unit 2: Reaction of Ammonium Carbonate with Solid Waste Gypsum
[0046] (NH4)2CO3 + CaSO4 = (NH4)2SO4 + CaCO3↓
[0047] Furthermore, a dedicated apparatus for implementing the method described above includes: an ammonium chloride pulverizing unit, an ultrafine wet mill, an ultrafine dry mill, an ammonium carbonate synthesis unit, a calcium chloride concentration and crystallization unit, a gypsum pretreatment unit, a high-gravity ammoniation reactor, a multiphase reactor, an aging tank, a closed diaphragm filter press, an ammonium sulfate evaporation and crystallization unit, and a nano-calcium carbonate drying and grinding unit, wherein the outlet of the ammonium carbonate synthesis unit is connected to the multiphase reactor.
[0048] Example 2:
[0049] like Figure 1 As shown in the figure, this invention provides a method for the co-production of solid waste gypsum and by-product ammonium chloride, comprising the following steps:
[0050] Step 1: The by-product ammonium chloride is pulverized into two streams, with the ammonium chloride being pulverized to 50 mesh. One stream reacts with calcium carbonate slurry in an ultrafine wet mill under slight negative pressure to prepare an ammonia-carbon dioxide mixture. The wet reaction temperature is 63℃, and the gauge pressure is -3.2 kPa, resulting in an ammonium bicarbonate solution. The other stream reacts with calcium oxide in an ultrafine dry mill under high negative pressure to prepare high-purity ammonia and solid calcium chloride. The gauge pressure of the dry reaction is -83 kPa. The ammonium bicarbonate solution and ammonia are then combined to synthesize high-purity ammonium carbonate at a temperature of 48℃. The calcium chloride produced by the wet and dry processes is combined and concentrated to prepare calcium chloride dihydrate. The calcium carbonate and calcium oxide are obtained from Pidgeon process magnesium slag and ammonia-soda process white mud.
[0051] Step 2: Solid waste gypsum (including phosphogypsum and titanium gypsum) is crushed, impurity removed, and pulped, and then sequentially fed into a high-gravity ammoniation reactor and a multiphase reactor. The reaction temperature of the multiphase reactor is 50℃ and the reaction time is 45min. It reacts with the high-purity ammonium carbonate prepared in Step 1 at 50℃ for 45min. After aging and separation by closed diaphragm filter press, the separation is carried out using a closed diaphragm filter press.
[0052] Step 3: The ammonium sulfate filtrate obtained by separation is evaporated, concentrated, crystallized and dried to obtain the ammonium sulfate product. The calcium carbonate filter cake is dried and ultra-finely ground to obtain the nano calcium carbonate product.
[0053] Secondly, the reaction principle of the above method is as follows:
[0054] Unit 1: Preparation of Ammonium Carbonate and Calcium Chloride from Ammonium Chloride Byproducts
[0055] 2NH4Cl + CaCO3 = CaCl2 + 2NH3↑ + CO2↑ + H2O
[0056] NH3 + CO2 + H2O = NH4HCO3
[0057] 2NH4Cl + CaO = CaCl2 + 2NH3↑ + H2O
[0058] NH4HCO3 + NH3 = (NH4)2CO3
[0059] Unit 2: Reaction of Ammonium Carbonate with Solid Waste Gypsum
[0060] (NH4)2CO3 + CaSO4 = (NH4)2SO4 + CaCO3↓
[0061] Furthermore, a dedicated apparatus for implementing the method described above includes: an ammonium chloride pulverizing unit, an ultrafine wet mill, an ultrafine dry mill, an ammonium carbonate synthesis unit, a calcium chloride concentration and crystallization unit, a gypsum pretreatment unit, a high-gravity ammoniation reactor, a multiphase reactor, an aging tank, a closed diaphragm filter press, an ammonium sulfate evaporation and crystallization unit, and a nano-calcium carbonate drying and grinding unit, wherein the outlet of the ammonium carbonate synthesis unit is connected to the multiphase reactor.
[0062] Example 3:
[0063] like Figure 1 As shown in the figure, this invention provides a method for the co-production of solid waste gypsum and by-product ammonium chloride, comprising the following steps:
[0064] Step 1: The by-product ammonium chloride is pulverized into two streams, with the ammonium chloride being pulverized to 60 mesh. One stream reacts with calcium carbonate slurry in an ultrafine wet mill under slight negative pressure to prepare an ammonia-carbon dioxide mixture. The wet reaction temperature is 65℃, and the gauge pressure is -3.5kPa, resulting in an ammonium bicarbonate solution. The other stream reacts with calcium oxide in an ultrafine dry mill under high negative pressure to prepare high-purity ammonia and solid calcium chloride. The gauge pressure of the dry reaction is -85kPa. The ammonium bicarbonate solution and ammonia are then combined to synthesize high-purity ammonium carbonate at a temperature of 50℃. The calcium chloride produced by the wet and dry processes is combined and concentrated to prepare calcium chloride dihydrate. The calcium carbonate and calcium oxide are obtained from steel slag, Pidgeon process magnesium slag, and ammonia-soda process white mud.
[0065] Step 2: Solid waste gypsum (including desulfurized gypsum, phosphogypsum, and titanium gypsum) is crushed, impurities removed, and pulped, and then sequentially fed into a high-gravity ammoniation reactor and a multiphase reactor. The reaction temperature in the multiphase reactor is 50°C and the reaction time is 45 min. It reacts with the high-purity ammonium carbonate prepared in Step 1 at 50°C for 45 min. After aging and separation by closed-loop diaphragm filter press, the separation is carried out using a closed-loop diaphragm filter press.
[0066] Step 3: The ammonium sulfate filtrate obtained by separation is evaporated, concentrated, crystallized and dried to obtain the ammonium sulfate product. The calcium carbonate filter cake is dried and ultra-finely ground to obtain the nano calcium carbonate product.
[0067] Secondly, the reaction principle of the above method is as follows:
[0068] Unit 1: Preparation of Ammonium Carbonate and Calcium Chloride from Ammonium Chloride Byproducts
[0069] 2NH4Cl + CaCO3 = CaCl2 + 2NH3↑ + CO2↑ + H2O
[0070] NH3 + CO2 + H2O = NH4HCO3
[0071] 2NH4Cl + CaO = CaCl2 + 2NH3↑ + H2O
[0072] NH4HCO3 + NH3 = (NH4)2CO3
[0073] Unit 2: Reaction of Ammonium Carbonate with Solid Waste Gypsum
[0074] (NH4)2CO3 + CaSO4 = (NH4)2SO4 + CaCO3↓
[0075] Furthermore, a dedicated apparatus for implementing the method described above includes: an ammonium chloride pulverizing unit, an ultrafine wet mill, an ultrafine dry mill, an ammonium carbonate synthesis unit, a calcium chloride concentration and crystallization unit, a gypsum pretreatment unit, a high-gravity ammoniation reactor, a multiphase reactor, an aging tank, a closed diaphragm filter press, an ammonium sulfate evaporation and crystallization unit, and a nano-calcium carbonate drying and grinding unit, wherein the outlet of the ammonium carbonate synthesis unit is connected to the multiphase reactor.
[0076] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for the co-production of solid waste gypsum and by-product ammonium chloride, characterized in that: Includes the following steps: Step 1: The by-product ammonium chloride is pulverized and divided into two streams. One stream reacts with calcium carbonate slurry under slight negative pressure in an ultrafine wet mill to prepare an ammonia-carbon dioxide mixture, which is then carbonized to obtain an ammonium bicarbonate solution. The other stream reacts with calcium oxide under high negative pressure in an ultrafine dry mill to prepare high-purity ammonia and solid calcium chloride. The ammonium bicarbonate solution and ammonia are then combined to obtain high-purity ammonium carbonate. The calcium chloride produced by the wet and dry processes is combined and concentrated to prepare calcium chloride dihydrate. Step 2: After being crushed, impurities removed, and pulped, the solid waste gypsum is sequentially fed into a high-gravity ammoniation reactor and a multiphase reactor, where it reacts with the high-purity ammonium carbonate prepared in Step 1 at 50°C for 45 minutes. After aging and separation by closed-loop membrane pressure filtration, the gypsum is further processed. Step 3: The ammonium sulfate filtrate obtained by separation is evaporated, concentrated, crystallized and dried to obtain the ammonium sulfate product. The calcium carbonate filter cake is dried and ultra-finely ground to obtain the nano calcium carbonate product.
2. The method for co-producing solid waste gypsum and by-product ammonium chloride according to claim 1, characterized in that: In step one, the ammonium chloride is pulverized to 40-60 mesh, the wet reaction temperature is 60-65℃, and the gauge pressure is -3 to -3.5 kPa; the dry reaction gauge pressure is -80 to -85 kPa; and the synthesis temperature of the high-purity ammonium carbonate is 45-50℃.
3. The method for co-producing solid waste gypsum and by-product ammonium chloride according to claim 1, characterized in that: In step two, the solid waste gypsum includes one or more of desulfurized gypsum, phosphogypsum, and titanium gypsum.
4. The method for co-producing solid waste gypsum and by-product ammonium chloride according to claim 1, characterized in that: In step two, the reaction temperature of the multiphase reactor is 50°C, the reaction time is 45 min, and a closed diaphragm filter press is used for separation.
5. The method for co-producing solid waste gypsum and by-product ammonium chloride according to claim 1, characterized in that: In step one, the calcium carbonate and calcium oxide are one or more of steel slag, Pijang process magnesium slag, and ammonia-soda process white mud.
6. A dedicated apparatus for implementing the method according to any one of claims 1-5, characterized in that: include: The system includes an ammonium chloride pulverizing unit, an ultrafine wet mill, an ultrafine dry mill, an ammonium carbonate synthesis unit, a calcium chloride concentration and crystallization unit, a gypsum pretreatment unit, a high-gravity ammoniation reactor, a multiphase reactor, an aging tank, a closed diaphragm filter press, an ammonium sulfate evaporation and crystallization unit, and a nano-calcium carbonate drying and grinding unit. The outlet of the ammonium carbonate synthesis unit is connected to the multiphase reactor.