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CN-122006685-A - Preparation method and application of iron-calcium synergistic solid waste-based dephosphorization filter material

CN122006685ACN 122006685 ACN122006685 ACN 122006685ACN-122006685-A

Abstract

The invention discloses a preparation method and application of an iron-calcium synergistic solid waste base dephosphorization filter material. According to the method, clay minerals containing Al 2 O 3 and SiO 2 or oily sludge with the oil content less than or equal to 5% wt are used as binders, calcium-containing solid waste is used as an active component, functional auxiliary ferric salt is added, and the iron-calcium synergistic solid waste-based dephosphorization filter material capable of removing phosphorus pollutants in water is prepared through pretreatment, mixing, granulation, drying, roasting and cooling treatment. Through introducing ferric salt and controlling the roasting temperature at 400-700 ℃, the calcium-containing phase which is easy to release OH‑ in solid waste can be converted into a stable phase which is easy to release Ca 2+ and does not release OH‑ , and meanwhile, an iron active site is constructed, so that an iron-calcium interface coupling effect is formed. Compared with the prior art, the invention realizes better adsorption effect while obviously reducing energy consumption, and the prepared filter material has wide raw material sources, low cost, high adsorption capacity and small fluctuation of effluent pH, and can be widely applied to the treatment of phosphorus-containing wastewater.

Inventors

  • MA XIAODONG
  • LI BENXING
  • LIU XIAOYAO

Assignees

  • 河北工业大学

Dates

Publication Date
20260512
Application Date
20260206

Claims (9)

  1. 1. The preparation method of the iron-calcium synergistic solid waste base dephosphorization filter material is characterized in that clay minerals containing Al 2 O 3 and SiO 2 or oily sludge with the oil content less than or equal to 5% wt are used as a binder, calcium-containing solid waste and functional auxiliary ferric salt are added, and the iron-calcium synergistic solid waste base dephosphorization filter material is obtained through pretreatment, mixing, granulation, drying, roasting and cooling treatment; The molar ratio of the calcium element in the calcium-containing solid waste to the iron element in the functional auxiliary ferric salt is 1-10:1; The roasting process is that roasting is carried out at 400-700 ℃ for 5-30 min.
  2. 2. The preparation method of the iron-calcium synergistic solid waste base dephosphorization filter material according to claim 1, wherein the functional auxiliary ferric salt is one or more of ferrous sulfate, ferric trichloride, polymeric ferric sulfate or ferric nitrate.
  3. 3. The preparation method of the iron-calcium synergistic solid waste-based dephosphorizing filter material according to claim 1, wherein the binder is one or more of bentonite, kaolin or oily sludge with the oil content less than or equal to 5% wt, and the sum of the mass contents of Al 2 O 3 and SiO 2 in the binder is more than or equal to 60%; The calcium-containing solid waste is one or more of carbide slag, papermaking white mud, steel slag or iron tailings, and the sum of the mass contents of CaO, ca (OH) 2 and CaCO 3 in the calcium-containing solid waste is more than or equal to 40 percent.
  4. 4. The preparation method of the iron-calcium synergistic solid waste-based dephosphorizing filter material is characterized by comprising, by mass, 20-40% of a binder, 30-50% of calcium-containing solid waste and 10-30% of a functional additive ferric salt.
  5. 5. The preparation method of the iron-calcium synergistic solid waste-based dephosphorizing filter material according to claim 1, which is characterized by comprising the following specific steps: 1) Preprocessing, namely grinding the binder and the calcium-containing solid waste through a 80-120 mesh sieve; 2) Mixing, namely adding ferric salt serving as a functional additive and the pretreated raw materials into a stirrer to mix for 5-10 min, wherein the stirring speed is 80-120 r/min; 3) Granulating, namely granulating the mixed materials in the step 2), and spraying deionized water according to the solid-to-liquid ratio of 1:0.5-1 in the granulating process to obtain spherical particles with the diameter of 6-10 mm; 4) Drying, namely drying the spherical particles prepared in the step 3) for 6-24 hours at room temperature, and then drying for 2-12 hours at 60-120 ℃; 5) Roasting, namely presintering the dried spherical particles for 5-30 min at 150-300 ℃, and roasting at 400-700 ℃ at a temperature rise rate of 5-10 ℃ per min for 5-30 min; 6) And (3) cooling, namely stopping heating, and cooling to room temperature to obtain the iron-calcium synergistic solid waste base dephosphorization filter material.
  6. 6. The method for preparing the iron-calcium synergistic solid waste-based dephosphorizing filter material according to claim 1, wherein the phase of the dephosphorizing filter material comprises anhydrite and anorthite, and also comprises ferric oxide or ferroferric oxide.
  7. 7. The preparation method of the iron-calcium synergistic solid waste-based dephosphorizing filter material according to claim 1, wherein the compressive strength of the dephosphorizing filter material obtained by the preparation method is 150-300N.
  8. 8. The application of the iron-calcium synergistic solid waste-based dephosphorization filter material obtained by the preparation method of any one of claims 1-7 is characterized in that the dephosphorization filter material is applied to the treatment of phosphorus-containing sewage, wherein the concentration of influent phosphorus pollutants is 0.1-50 mg/L, the influent flow is 10-500 m 3 /d, the empty bed contact time is 1-5 d, the pH value fluctuation range of effluent water is less than 0.8, and the adsorption capacity of the filter material reaches 30-65 mg/g.
  9. 9. The use according to claim 8, wherein the dephosphorizing filter material produces brushite or hydroxyapatite after adsorption of phosphate, and further comprises calcium iron phosphate or triclinite.

Description

Preparation method and application of iron-calcium synergistic solid waste-based dephosphorization filter material Technical Field The invention belongs to the technical field of water pollution control, and particularly relates to a preparation method and application of an iron-calcium synergistic solid waste base dephosphorization filter material. Background The eutrophication of water body caused by phosphorus pollution, the excessive accumulation of phosphorus serving as a key limiting nutrient element for biological growth of a water ecological system breaks the balance of the water ecological system, triggers large-scale outbreak of algal bloom, leads to the exhaustion of dissolved oxygen of the water body and the deterioration of water quality, further causes death of fish and other organisms, finally causes the collapse of the ecological system, and seriously threatens the safety of drinking water and sustainable development of ecological environment. In recent years, industrial solid wastes (such as steel slag, iron tailings and carbide slag) are widely used for preparing cheap solid waste-based dephosphorizing filter materials due to low cost, wide sources and large yield. The active components of the filter material are calcium-containing phases, and have two defects that firstly, alkaline calcium-containing phases (such as calcium silicate, calcium oxide, calcium carbonate and the like) have limited capability of releasing Ca 2+ in water to restrict the dephosphorization performance, and secondly, the phases release OH - in the dephosphorization process, so that the pH of water body is obviously increased to harm the aquatic ecosystem. Engineering application needs to simultaneously consider adsorption efficiency and pH stability, but the existing materials are difficult to consider. For example, chinese patent CN202011073114.0 discloses a dephosphorization ceramsite in wastewater, which is obtained by adopting the combination of fly ash and calcium-containing solid waste carbide slag and roasting at 800-1050 ℃, and the pH value of the dephosphorization ceramsite is adjusted to 7.0-8.5 under the condition of no additional acid. Chinese patent CN202410393623.3 discloses a functional ceramsite for efficiently purifying phosphorus-containing wastewater, a preparation method and application, wherein desulfurized gypsum and salt gypsum are used as functional auxiliary agents to relieve pH change caused in the reaction process of a binder and calcium oxide solid waste of carbide slag, and the roasting temperature is 1150-1200 ℃. The prior achievements of the applicant can stabilize the pH, but the energy consumption in the preparation of the ceramsite is higher, the relative cost is higher, and the technical problem to be solved is how to prepare the low-cost dephosphorization filter material with lower energy consumption on the premise of improving the dephosphorization effect and ensuring the pH stability. Disclosure of Invention The invention aims to provide a preparation method and application of an iron-calcium synergistic solid waste base dephosphorization filter material, and the triple targets of high-efficiency dephosphorization, stable pH and reduced energy consumption are synchronously realized through iron-calcium interface coupling. Through the ferric salt serving as a functional auxiliary agent and the regulation and control of roasting conditions, the calcium-containing phase in solid waste is promoted to be converted into a structure which is easier to release Ca 2+ and does not release OH - (under the traditional roasting conditions, calcium oxide is easy to form after roasting, and the calcium oxide forms easily form hydroxyl in water, so that the pH value of water body is increased), and meanwhile, fe 2+/Fe3+ active sites are introduced, so that efficient dephosphorization and pH stability are synchronously realized, and the technical bottleneck of the existing material is broken through. The method has the advantages of simple preparation process, low cost and the like, and solves the problems of the common use of the calcium-containing functional filter material that the pH of the water body is raised and the phosphate adsorption capacity is poor at neutral pH. The technical scheme adopted by the invention is as follows: The preparation method of the iron-calcium synergistic solid waste base dephosphorization filter material comprises the steps of taking clay minerals containing Al 2O3 and SiO 2 or oily sludge with the oil content less than or equal to 5 wt% as a binder, adding calcium-containing solid waste and functional auxiliary ferric salt, and carrying out pretreatment, mixing, granulating, drying, roasting and cooling treatment to obtain the iron-calcium synergistic solid waste base dephosphorization filter material; The molar ratio of the calcium element (calculated by Ca) in the calcium-containing solid waste to the iron element (calculated by Fe) in the functional auxili