CN114180709A - Method for preparing porous steam-cured phosphorus removal biological filter material by utilizing waste foundry clay sand - Google Patents
Method for preparing porous steam-cured phosphorus removal biological filter material by utilizing waste foundry clay sand Download PDFInfo
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- CN114180709A CN114180709A CN202111559587.6A CN202111559587A CN114180709A CN 114180709 A CN114180709 A CN 114180709A CN 202111559587 A CN202111559587 A CN 202111559587A CN 114180709 A CN114180709 A CN 114180709A
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- filter material
- biological filter
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/105—Phosphorus compounds
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- Biodiversity & Conservation Biology (AREA)
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- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention belongs to the technical field of resource recycling, and particularly relates to a method for preparing a porous autoclaved curing dephosphorization biological filter material by using waste foundry clay sand, which comprises the following steps: (1) according to the requirement of the autoclaved concrete technology on the particle size of the raw materials, ball-milling and sieving the waste foundry clay sand; (2) uniformly mixing the sieved waste sand powder, cement, lime, fly ash, zirconium hydroxide, gypsum and the like for later use; (3) adding the adhesive and the pore-forming agent in proportion, and uniformly stirring to obtain a premix; (4) adding a proper amount of water into the premix, and preparing raw material balls with a certain size by using a granulator; (5) performing pre-curing and autoclaved curing operation on the raw material balls according to the technical requirements of conventional autoclaved curing concrete; (6) and (6) discharging. The invention can effectively recycle the waste foundry clay sand, and prepare the porous autoclaved curing dephosphorization biological filter material with high added value, thereby having high economic and environmental benefits.
Description
Technical Field
The invention belongs to the technical field of waste recycling, and particularly relates to a method for preparing a porous steam-cured dephosphorization biological filter material by utilizing an autoclaved aerated concrete technology to recycle resources of waste foundry clay sand.
Background
Casting is a fundamental industry in manufacturing. After the 21 st century, the foundry industry is under dual pressures of both resources and the environment. The solid wastes generated by casting are mainly waste sand and waste ash, and account for more than 90 percent of the total amount of the solid wastes. The waste foundry sand can be classified into clay waste sand, water glass waste sand, resin, coated sand and the like. For the general waste foundry clay sand, the components generally comprise quartz sand (crushed or changed in shape), unreacted clay and various additives (bentonite, coal powder and the like), sintered dead clay, clay which forms micro powder after being calcined (high-temperature reaction), scrap iron and additives; generally has the characteristics of no fine and uneven particles, stable physicochemical property, no water solubility, high temperature resistance and the like.
In the general clay sand casting process, a certain amount of casting waste sand is generated due to the reasons of sand explosion caused by heating, loss of bonding performance caused by dehydration of crystalline bentonite, partial consumption of coal powder and the like, and is removed from a sand system by a dust removal process in the recycling process. The waste clay sand mainly comprises quartz sand (crushed or changed in shape, the content of the crushed or changed shape is 85-95%, the weight ratio is the same as below), unreacted clay and various additives (bentonite, coal dust and the like, 2-3%), sintered dead clay (3-5%), clay which forms micro powder after being sintered and injected, and scrap iron (3-5%). The composite material comprises 90-95 wt% of quartz sand, 3-5 wt% of clay and 2-4 wt% of coal powder.
The key technology of phosphorus adsorption is that the large specific surface area of the adsorbent is utilized to make phosphorus carry out adhesion adsorption, surface precipitation or ion exchange on active sites on the surface of the adsorbent, thereby realizing the transfer of phosphorus from a water phase to a solid phase and achieving the separation effect. At present, the commonly used activated carbon in China is poor in adsorption capacity, complex in recycling, expensive and high in treatment cost. Therefore, it is necessary to develop an inexpensive and efficient adsorbent.
The calcium silicate substance has the capability of slowly releasing calcium ions and alkalinity, is easy to be made into porous materials with various shapes, and has better adsorption effect on phosphate radicals in water. The tobermorite in the autoclaved concrete block can provide calcium ions, so that the tobermorite is combined with phosphate radicals in water, and stable calcium hydroxy phosphate is generated on the surface of the tobermorite to realize phosphorus removal. The zirconium ion is generally considered to have strong phosphate complexing ability, the zirconium modified material also has remarkable effect at present when being used as a phosphorus removal adsorbent, and the hydrated oxide of the tetravalent zirconium has rich hydroxyl ions and water molecules, and the hydroxyl ions and the water molecules participate in ligand substitution and can adsorb phosphate in aqueous solution, so that the purpose of removing phosphorus is achieved.
The document (Zhengying et al, development and casting of used sand autoclaved brick, 2007, 56 (9), p 1001-1004) discloses a method for preparing a solid autoclaved brick by using used casting sand, fly ash and rock salt as main raw materials, adding a certain amount of slaked lime and a composite additive, and performing processes of rolling, pressing, autoclaving and the like, wherein the quality of the solid autoclaved brick meets the performance requirements of autoclaved sand-lime brick (GB 11945-1999), and the solid autoclaved brick is mainly used for building materials. However, no report is found at present that the porous biological filter material is prepared by using waste foundry sand and combining an autoclaved concrete technology, and the porous biological filter material is particularly applied to sewage dephosphorization.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method for preparing the porous autoclaved curing dephosphorization biological filter material by using the waste foundry clay sand achieves the purposes of comprehensively utilizing the waste foundry sand and changing waste into valuable. By means of the rapid complexation principle of zirconium ions and phosphate radicals, aiming at the increasingly strict phosphorus removal rate requirement of sewage treatment, the autoclaved porous phosphorus removal biological filter material is prepared, can meet the current sewage phosphorus removal requirement, can achieve the purpose of recycling wastes, and has extremely high economic, environmental and social benefits.
The invention relates to a method for preparing a porous autoclaved curing dephosphorization biological filter material by utilizing waste foundry clay sand, which specifically comprises the following steps:
(1) according to the requirement of the autoclaved concrete technology on the particle size of the raw materials, ball-milling and sieving waste foundry clay sand, wherein the mesh number is not less than 200 meshes;
(2) uniformly mixing the sieved waste sand powder (20-40 wt%, the same below), cement (30-40%), fly ash (5-15%), lime (10-15%), zirconium hydroxide (0.5-1%), gypsum (the balance) and the like for later use;
(3) adding 0.5-1% of adhesive and 0.06-0.1% of pore-forming agent in proportion, and uniformly stirring to obtain a premix;
(4) adding a proper amount of water (generally accounting for about 30 percent of the weight of the powder) into the premix, and preparing raw material balls with a certain size by using a granulator;
(5) performing precuring and autoclaved curing operation on the raw material balls according to the technical requirement of conventional autoclaved curing concrete;
(6) and discharging.
Wherein:
the grain size of all the powder in the step (1) and the step (2) is not less than 200 meshes.
The zirconium hydroxide used in step (2) may be commercial industrial grade zirconium hydroxide, or alternatively, zirconium oxychloride octahydrate may be added in an equimolar amount (based on the amount of zirconium element), preferably commercial zirconium hydroxide.
The cement in the step (3) is ordinary portland cement, preferably over 42.5MPa type ordinary portland cement.
The pore-forming agent in the step (3) is special aluminum powder for commercial autoclaved concrete, and the used binder is one of commercial dispersible rubber powder, polyvinylpyrrolidone or polyethylene oxide, preferably dispersible rubber powder.
The granulation size in the step (4) is adjustable, and is generally 10-50 mm, preferably 25-30 mm.
The pre-curing condition in the step (5) is 50-70 ℃, and the initial curing time is 1.5-2 hours, preferably 60 ℃, and 1.5 hours.
And (5) performing autoclaved curing at 150 ℃ for 8-10 hours, preferably 8 hours.
Compared with the prior art, the invention has the following beneficial effects:
1. the production process is simple, the raw materials are few in variety, and the waste foundry clay sand is used as the autoclaved aerated concrete filter material aggregate, so that the waste is changed into valuable, and the resources and the production cost are saved.
2. In the autoclaved curing process, calcium hydroxide in the material, free silica in quartz sand and alumina react to obtain tobermorite; and the flaky crystallized tobermorite and the waste sand aggregate are mutually interwoven to form a compact network structure, which is more beneficial to improving the strength of the filter material.
3. The invention does not need complex treatment such as magnetic separation and iron removal pretreatment on the casting waste sand, and the existence of the scrap iron increases the compressive strength and the dry bulk density of the filter material, thereby improving the final strength of the filter material to a certain extent.
4. The invention has reasonable component proportion, and uses high-strength ordinary portland cement, so that the compression strength of the biological filter material barrel is improved to be more than 12MPa, and the application range of the biological filter material barrel is further expanded.
5. The material produced by the autoclaved aerated concrete technology has the characteristics of low density, large specific surface area and porosity; therefore, the biological filter material prepared by the invention has larger specific surface area which can be more than 5 times of that of a common filter material, and has more obvious advantages in the aspect of water treatment application.
6. According to the invention, zirconium hydroxide is added in the mixed material production process before cement solidification, so that the mixed material is wrapped in the mullite internal structure, the slow release and complex phosphorus removal effects of zirconium ions are promoted to a certain extent, and the mullite has a phosphorus removal effect, so that the filter material has a more lasting phosphorus removal effect, and the reproducibility is higher than that of a lanthanum-containing phosphorus removal filter material.
7. The production process of the biological filter material can be applied to the existing autoclaved aerated concrete production process, the production cost is low, and the market competitive advantage of the product is enhanced.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments in order to make the technical field better understand the scheme of the present invention.
Example 1
(1) According to the requirement of the autoclaved concrete technology on the particle size of the raw materials, ball-milling and sieving the waste foundry clay sand, and sieving the waste foundry clay sand by a 200-mesh sieve;
(2) uniformly mixing the sieved waste sand powder (35% by weight, the same below), cement (35%), fly ash (15%), lime (10%), zirconium hydroxide (0.7%), gypsum (the balance, 4.3%) and the like for later use;
(3) adding the adhesive (1%) and the pore-forming agent (0.06%) in proportion, and uniformly stirring to prepare a premix;
(4) adding 30 percent (weight ratio) of water into the premix, and preparing raw material balls with the diameter of 40mm by using a granulator;
(5) pre-curing (60 ℃, 2 hours) and performing autoclaved curing (150 ℃, 8 hours) on the raw material balls according to the technical requirements of conventional autoclaved curing concrete;
(6) and discharging.
Example 2
(1) According to the requirement of the autoclaved concrete technology on the particle size of the raw materials, ball-milling and sieving the waste foundry clay sand, and sieving the waste foundry clay sand by a 200-mesh sieve;
(2) uniformly mixing the sieved waste sand powder (35% by weight, the same below), cement (30%), fly ash (15%), lime (15%), zirconium hydroxide (0.8%), gypsum (the balance, 4.2%) and the like for later use;
(3) adding the adhesive (1%) and the pore-forming agent (0.06%) in proportion, and uniformly stirring to prepare a premix;
(4) adding 30 percent (weight ratio) of water into the premix, and preparing raw material balls with the diameter of 30mm by using a granulator;
(5) pre-curing (60 ℃, 1.5 hours) and performing autoclaved curing (150 ℃, 8 hours) on the raw material balls according to the technical requirements of conventional autoclaved curing concrete;
(6) and discharging.
Example 3
(1) According to the requirement of the autoclaved concrete technology on the particle size of the raw materials, ball-milling and sieving the waste foundry clay sand, and sieving the waste foundry clay sand by a 200-mesh sieve;
(2) uniformly mixing the sieved waste sand powder (30% by weight, the same below), cement (40%), fly ash (15%), lime (10%), zirconium hydroxide (1%), gypsum (the balance, 4%) and the like for later use;
(3) adding the adhesive (1%) and the pore-forming agent (0.06%) in proportion, and uniformly stirring to prepare a premix;
(4) adding 30 percent (weight ratio) of water into the premix, and preparing raw material balls with the diameter of 45mm by using a granulator;
(5) and performing precuring (60 ℃, 2 hours) and autoclaved curing (150 ℃, 9 hours) on the raw material balls according to the technical requirements of conventional autoclaved curing concrete.
(6) And discharging.
The performance indexes of the biological filter material prepared in the embodiment 1-3, such as bulk density, specific surface area, porosity, cylinder pressure strength, phosphorus removal efficiency and the like, are measured according to the existing national standard, and specific measurement results are shown in table 1.
TABLE 1 results of measurements on biofilters prepared in examples 1-3
Of course, the foregoing is only a preferred embodiment of the invention and should not be taken as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.
Claims (7)
1. A porous steam-curing dephosphorization biological filter material prepared by using waste foundry clay sand is characterized in that: the method comprises the following steps:
(1) according to the requirement of the autoclaved concrete technology on the particle size of the raw materials, ball-milling and sieving the waste foundry clay sand;
(2) uniformly mixing the sieved waste sand powder, cement, lime, fly ash, zirconium hydroxide, gypsum and the like for later use;
(3) adding the adhesive and the pore-forming agent in proportion, and uniformly stirring to prepare a premix;
(4) adding a proper amount of water into the premix, and preparing raw material balls with a certain size by using a granulator;
(5) performing precuring and autoclaved curing operation on the raw material balls according to the technical requirements of conventional autoclaved curing concrete;
(6) and discharging.
2. The method for preparing the porous biological filter material for steam culture and phosphorus removal by using the waste foundry clay sand as claimed in claim 1, which is characterized in that: the number of the sieved meshes in the step (1) is not less than 200 meshes.
3. The method for preparing the porous biological filter material for steam culture and phosphorus removal by using the waste foundry clay sand as claimed in claim 1, which is characterized in that: the proportion of zirconium hydroxide in the step (2) should not be more than 1%.
4. The method for preparing the porous biological filter material for steam culture and phosphorus removal by using the waste foundry clay sand as claimed in claim 1, which is characterized in that: the cement in the step (2) is ordinary portland cement.
5. The method for preparing the porous biological filter material for steam culture and phosphorus removal by using the waste foundry clay sand as claimed in claim 1, which is characterized in that: and (3) the pore-forming agent in the step (2) is aluminum powder.
6. The method for preparing the porous biological filter material for steam culture and phosphorus removal by using the waste foundry clay sand as claimed in claim 1, which is characterized in that: in the step (2), the binder is one of dispersible rubber powder, polyvinylpyrrolidone, carboxymethyl cellulose or polyethylene oxide.
7. The method for preparing the porous biological filter material for steam culture and phosphorus removal by using the waste foundry clay sand as claimed in claim 1, which is characterized in that: in the step (4), the curing temperature is 150 ℃, and the curing time is 8-10 hours.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111559587.6A CN114180709A (en) | 2021-12-20 | 2021-12-20 | Method for preparing porous steam-cured phosphorus removal biological filter material by utilizing waste foundry clay sand |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111559587.6A CN114180709A (en) | 2021-12-20 | 2021-12-20 | Method for preparing porous steam-cured phosphorus removal biological filter material by utilizing waste foundry clay sand |
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| Publication Number | Publication Date |
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| CN114180709A true CN114180709A (en) | 2022-03-15 |
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| CN202111559587.6A Withdrawn CN114180709A (en) | 2021-12-20 | 2021-12-20 | Method for preparing porous steam-cured phosphorus removal biological filter material by utilizing waste foundry clay sand |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115108648A (en) * | 2022-05-23 | 2022-09-27 | 西南交通大学 | Water body in-situ phosphate enrichment device |
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2021
- 2021-12-20 CN CN202111559587.6A patent/CN114180709A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115108648A (en) * | 2022-05-23 | 2022-09-27 | 西南交通大学 | Water body in-situ phosphate enrichment device |
| CN115108648B (en) * | 2022-05-23 | 2023-10-20 | 西南交通大学 | Water normal position enrichment phosphate device |
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Application publication date: 20220315 |
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