CN111451439A - Regeneration method of Papu resin used sand - Google Patents
Regeneration method of Papu resin used sand Download PDFInfo
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- CN111451439A CN111451439A CN202010386959.9A CN202010386959A CN111451439A CN 111451439 A CN111451439 A CN 111451439A CN 202010386959 A CN202010386959 A CN 202010386959A CN 111451439 A CN111451439 A CN 111451439A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
- B22C5/04—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by grinding, blending, mixing, kneading, or stirring
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/66—Monolithic refractories or refractory mortars, including those whether or not containing clay
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Mold Materials And Core Materials (AREA)
Abstract
The invention relates to a regeneration method of Papu resin used sand, which comprises the following steps: feeding used sand: mechanically crushing the Papu resin used sand into single particles; thermal regeneration: roasting the crushed used sand at high temperature to obtain hot sand; thermal mechanical-chemical regeneration: and putting the thermal-state sand into negative-pressure closed mechanical milling equipment, and spraying atomized acid liquor in a shower manner to obtain the reclaimed sand. The method has the advantages of low operation cost, high efficiency and good quality of the reclaimed sand; the waste heat of the sand is fully utilized, and the policy of energy conservation and emission reduction is met; the method does not need to reuse wet regeneration, removes the alkaline oxide of the regenerated sand, and solves the bottleneck problem of thermal regeneration; the advantages of thermal method-mechanical-chemical regeneration are combined, industrial production can be realized, the efficiency is high, the effect is good, additional heat energy supplement and equipment addition are not needed, chemical regeneration under a thermal state can be realized, the acid consumption value of the regenerated sand is low, and the workability is good.
Description
Technical Field
The invention belongs to the technical field of reclaimed sand, and particularly relates to a method for regenerating Papu resin used sand.
Background
The high-speed development of high-speed rails, heavy trucks, loaders, ships, nuclear industries and the like in China has more and more requirements on large steel castings, is a very good opportunity for the casting industry in China, needs to produce excellent large steel castings, needs mature casting technology and needs excellent molding materials for matching, and common alkali phenolic self-hardening sand, Papu resin sand, furan resin sand, Bonni resin sand, sodium silicate sand and the like, wherein the Papu resin sand has the characteristics of good strength, high efficiency and wide application range and is adopted by a plurality of casting plants.
The ratio of casting and molding material is typically 1: 1, i.e. 1 ton of moulding material sand is consumed per 1 ton of casting produced, and the amount of discharged waste sand is 1 ton as well. Millions of tons of casting production in China per year, the emission of such huge amounts of waste sand, the pressure on the natural environment and the company costs is not insignificant! The improvement of the regeneration process of the used casting sand, the replacement of new sand for cyclic utilization is an urgent requirement and a necessary trend for realizing energy conservation and emission reduction of enterprises and green production of the casting industry in China.
At present, no advanced method exists for the regeneration treatment of the used parade resin sand, the reutilization rate of the conventional regenerated sand method is less than 60%, the problems of low strength of molding sand and many pores of a casting can be solved only by adopting a facing sand process of new sand in the production of a complex steel casting, the problem of high acid consumption value of the regenerated sand is not solved all the time, and the low initial strength of the slow solidification of the molding sand when the temperature is low in winter also exists, so that some steel casting enterprises do not dare to adopt the used sand regeneration process.
The present invention has been made in view of the above circumstances.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a regeneration method of Papu resin used sand, which has the advantages of high regeneration utilization rate, high removal rate of residues on the surface of the used sand, low operation cost and high efficiency.
In order to achieve the purpose, the invention adopts the following technical scheme:
a regeneration method of Papu resin used sand comprises the following steps:
(1) feeding used sand: mechanically crushing the Papu resin used sand into single particles;
(2) thermal regeneration: roasting the crushed used sand at high temperature to obtain hot sand;
(3) thermal mechanical-chemical regeneration: and putting the thermal-state sand into negative-pressure closed mechanical milling equipment, and spraying atomized acid liquor in a shower manner to obtain the reclaimed sand.
In the step (1), the used sand is mechanically crushed into single particles, and the hot roasting effect is influenced because part of blocky sand cores exist in the used sand.
Further, the roasting temperature in the step (2) is 600-.
Further, the roasting temperature in the step (2) is 700 ℃, and the roasting time is 4.5 h.
The longer the roasting time, the better the effect, but the energy consumption increase is obvious, the purpose is to remove low-melting point materials and resin films in the used sand and keep the sand temperature.
The purpose of the invention adopting the roasting is as follows:
(1) when the roasting temperature is too high, alkaline oxides (sodium oxide, calcium oxide, potassium oxide and aluminum oxide) in the waste sand react with silicon dioxide to be ceramized, and the alkaline oxides are firmly adsorbed on the surface of silica sand after being cooled and are difficult to remove.
(2) The firing temperature is too low, and low-melting substances, residual resin films, and the like cannot be sufficiently removed.
The casting pouring temperature is 1300-1500 ℃, the temperature of sand near molten metal exceeds 1000 ℃, for large steel castings, the sand particles are continuously heated, the residues on the sand surface are ceramized, the regenerated sand is thicker and thicker after ceramization, the coating property of the sand and resin is reduced, the strength is obviously reduced, and the sand is difficult to remove by a thermal method.
Secondly, the alkaline substances in the reclaimed sand can accelerate the resin curing reaction, reduce the service time of the core sand, reduce the fluidity of the core sand and reduce the strength of the core sand.
Further, the temperature of the hot sand in the steps (2) and (3) is 100-400 ℃.
Further, H in the acid liquor in the step (3)+The concentration of (b) is 0.05-1 mol/L.
Further, the acid solution is obtained by dissolving one or more of hydrochloric acid, sulfuric acid, phosphoric acid, carbonic acid, oxalic acid, hydrosulfuric acid, nitric acid, formic acid, acetic acid and propionic acid in water. The residues on the surface of the used sand are alkaline, acid consumption value of the reclaimed sand is reduced by using acid liquor, the acid is dissolved in water, and H is controlled+In a concentration of 0.05-1 mol/L, H+If the concentration is too low, the chemical reaction efficiency of the acid liquid and the alkaline oxide is low, the implementation effect is not ideal, and if the concentration is too high, equipment is corroded.
Further, in the mechanical grinding equipment in the step (3), the rotating wheels are used for driving the sand grains to collide and rub with each other, salt generated on the surfaces of the sand grains is separated, and an induced air negative pressure system is used for collecting and removing the salt.
The hot sand enters mechanical grinding equipment, under the drive of a roller, the sand is in a boiling state, and atomized acid liquor is sprayed, is uniformly contacted with the sand and chemically reacts with alkaline substances on the surface of the sand to generate salt; the water is evaporated by the heat of the sand in the hot state.
Further, the water content of the reclaimed sand in the step (3) is less than or equal to 0.5 percent.
Further, the acid consumption value of the reclaimed sand in the step (3) is 3.0-5.0 ml.
Wherein, the adding amount of the acid in the step (3) is determined according to the acid consumption value of the hot sand, the adding amount is increased correspondingly when the acid consumption value of the hot sand is higher, for example, the acid consumption value of the hot sand is 10ml, namely 10ml of hydrochloric acid (molar concentration is 0.1 mol/L) is consumed for 50g of sand, and the threshold value of the adding of the acid is that 10ml of 0.1 mol/L acid is used for neutralizing every 50g of sand.
The commercial hydrochloric acid with the mass fraction of 37% has the molar concentration of 12 mol/L, and the addition amount per ton of the sand acid is calculated according to the following formula:
the required amount of hydrochloric acid is added into the clear water, and the amount of water is controlled by the following steps:
the amount of acid liquor (water + acid) is controlled by the evaporable water amount of the sand temperature, the water content of the reclaimed sand and the temperature of the finished reclaimed sand, the water content of the reclaimed sand is less than or equal to 0.5 percent, and the strength of core making can be reduced if the water content is too high.
The reclaimed sand temperature directly influences the resin curing, and the optimal using temperature of the Papu resin (including cold cores, alkali phenolic aldehyde and the like) is 15-35 ℃, if the temperature is higher than 35 ℃, the solvent is promoted to volatilize and the strength is reduced if the temperature is an open type sand mixing bin; in addition, too high sand temperature can accelerate curing, and the formability and the service time of the sand core are influenced; the viscosity of the resin below 15 ℃ will increase, affecting the uniformity of sand and resin coating and affecting the uniformity of sand core strength.
The used sand treated by the method can realize that:
(1) the removal rate of the residues on the surface of the waste sand is more than or equal to 95 percent, and the ignition loss is less than or equal to 0.15 percent;
(2) the acid consumption value of the reclaimed sand is consistent with that of the new sand;
(3) the reclaimed sand can replace new sand by 100 percent for core production;
(4) the temperature of the reclaimed sand is 20-35 ℃, and is controllable.
Compared with the prior art, the invention has the beneficial effects that:
(1) the method has the advantages of simple equipment, low operation cost and good quality of the reclaimed sand; the waste heat of the hot reclaimed sand is fully utilized, the neutralization reaction rate of acid liquor and alkaline oxide is accelerated, and the policy of energy conservation and emission reduction is met; the method has the advantages of combining the advantages of thermal method-mechanical-chemical regeneration, fully removing alkaline oxides on the surface of the used sand, solving the bottleneck problem of thermal method regeneration, not needing to additionally implement a wet regeneration process, realizing industrial production, having high efficiency and good effect, not needing to additionally supplement heat energy and increase equipment, having low acid consumption value of the regenerated sand and good workability;
(2) the temperature and the water content of the reclaimed sand can be controlled by adjusting the addition of water, and the reclaimed sand can be directly applied to core making production to get rid of the constraint on the environmental temperature; for winter, especially in the north, the new sand must be heat treated; in summer, particularly in the south, the reclaimed sand needs to be cooled, and if the reclaimed sand is processed by a conventional heating method, an additional cooling system is needed to ensure that the produced reclaimed sand can meet the requirement of timely core making production.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
The used Pi-Pu resin sand selected in the following examples and comparative examples is the same batch of used sand, and the quality and the performance are basically consistent.
Example 1
The regeneration method of the used kapok resin sand in the embodiment comprises the following steps:
(1) feeding used sand: mechanically crushing the Papu resin used sand into single particles;
(2) thermal regeneration: roasting the used sand subjected to magnetic separation at 600 ℃ for 8 hours to obtain hot sand, wherein the temperature of the hot sand is 400 ℃;
(3) thermal mechanical-chemical regeneration: putting the hot sand into a negative pressure closed mechanical grinding device, driving the sand to be in a boiling state under the drive of a roller, and spraying atomized acid liquor in a shower mode, wherein the acid liquor is obtained by dissolving hydrochloric acid in water, and H in the acid liquor+The concentration of the acid liquor is 0.05 mol/L, and the acid liquor isThe sand grains are uniformly contacted and chemically reacted with alkaline substances on the surfaces of the sand grains to generate salt, water is evaporated by using the heat of the sand in a thermal state, the rotating wheel is used for driving the sand grains to collide and rub with each other, the salt on the surfaces of the sand is separated, and an induced air negative pressure system is used for collecting and removing the salt to obtain reclaimed sand.
Example 2
The regeneration method of the used kapok resin sand in the embodiment comprises the following steps:
(1) feeding used sand: mechanically crushing the Papu resin used sand into single particles;
(2) thermal regeneration: roasting the used sand subjected to magnetic separation at 700 ℃ for 4.5 hours to obtain hot sand, wherein the temperature of the hot sand is 250 ℃;
(3) thermal mechanical-chemical regeneration: putting the hot sand into a negative pressure closed mechanical grinding device, driving the sand to be in a boiling state under the drive of a roller, and spraying atomized acid liquor in a shower mode, wherein the acid liquor is obtained by dissolving acetic acid in water, and H in the acid liquor+The concentration of the acid liquor is 0.5 mol/L, the acid liquor is uniformly contacted with sand grains and chemically reacts with alkaline substances on the surfaces of the sand grains to generate salt, the heat of the sand in a thermal state is utilized to evaporate water, the rotating wheels are utilized to drive the sand grains to collide and rub with each other, the salt on the surfaces of the sand is separated, and an induced air negative pressure system is utilized to collect and remove the salt to obtain the reclaimed sand.
Example 3
The regeneration method of the used kapok resin sand in the embodiment comprises the following steps:
(1) feeding used sand: mechanically crushing the Papu resin used sand into single particles;
(2) thermal regeneration: roasting the used sand subjected to magnetic separation at 600 ℃ for 1h to obtain hot sand, wherein the temperature of the hot sand is 100 ℃;
(3) thermal mechanical-chemical regeneration: the hot sand is put into a negative pressure closed mechanical grinding device, and under the drive of a roller, the sand is positioned "Boiling, spraying atomized acid solution in water with oxalic acid dissolved in H+The concentration of 1 mol/L, the even and sand grain contact of acidizing fluid to take place chemical reaction with the alkaline material on sand grain surface, produce the salt, utilize the heat of sand under the hot state to evaporate moisture, utilize runner drive between the sand grain collision each other, rub, separate the salt on sand surface, utilize induced air negative pressure system to collect and get rid of, obtain the reclaimed sand.
Comparative example 1
The regeneration method of the used Papu resin sand in the comparative example is the same as that in the example 2, except that the step (2) is removed, the used sand after magnetic separation is directly put into mechanical grinding equipment, and atomized acid liquor is sprayed for treatment.
Comparative example 2
The regeneration method of the used Papu resin sand of the comparative example is the same as that of the example 2, except that no acid solution is sprayed in the step (3).
Test example 1
The reclaimed sand obtained by the methods of examples 1 to 3 and comparative examples 1 to 2 was subjected to the measurement of the quality properties, and the results are shown in Table 1.
TABLE 1
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (9)
1. The regeneration method of the used Papu resin sand is characterized by comprising the following steps:
(1) feeding used sand: mechanically crushing the Papu resin used sand into single particles;
(2) thermal regeneration: roasting the crushed used sand at high temperature to obtain hot sand;
(3) thermal mechanical-chemical regeneration: and putting the thermal-state sand into negative-pressure closed mechanical milling equipment, and spraying atomized acid liquor in a shower manner to obtain the reclaimed sand.
2. The method for regenerating depsipoly resin used sand as claimed in claim 1, wherein the calcination temperature in the step (2) is 600-750 ℃ and the calcination time is 1-8 h.
3. The regeneration method of Papu resin used sand according to claim 2, wherein the calcination temperature in the step (2) is 700 ℃ and the calcination time is 4.5 h.
4. The method for regenerating depsipoly resin used sand as claimed in claim 1, wherein the temperature of the hot sand in the steps (2) and (3) is 100-400 ℃.
5. The method for regenerating depside used resin sand according to claim 1, wherein H in the acid solution in the step (3)+The concentration of (b) is 0.05-1 mol/L.
6. The method for regenerating Papu resin used sand according to claim 1 or 5, wherein the acid solution is one or more selected from hydrochloric acid, sulfuric acid, phosphoric acid, carbonic acid, oxalic acid, hydrosulfuric acid, nitric acid, formic acid, acetic acid and propionic acid dissolved in water.
7. The method for regenerating depsipoly resin used sand according to claim 1, wherein in the step (3), the mechanical grinding equipment drives the sand grains to collide and rub with each other by using a rotating wheel, so as to separate salt generated on the surfaces of the sand grains, and an induced air negative pressure system is used for collecting and removing the salt.
8. The method for regenerating depsipoly resin used sand according to claim 1, wherein the water content of the regenerated sand in the step (3) is less than or equal to 0.5%.
9. The regeneration method of Papu resin used sand according to claim 1, wherein the acid consumption value of the regenerated sand in the step (3) is 3.0-5.0 ml.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010386959.9A CN111451439A (en) | 2020-05-09 | 2020-05-09 | Regeneration method of Papu resin used sand |
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| CN202010386959.9A CN111451439A (en) | 2020-05-09 | 2020-05-09 | Regeneration method of Papu resin used sand |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114101577A (en) * | 2021-11-24 | 2022-03-01 | 北京仁创砂业铸造材料有限公司 | Regeneration method of casting 3D printing waste sand |
| CN114749599A (en) * | 2022-03-31 | 2022-07-15 | 广西兰科资源再生利用有限公司 | Micro-wet method treatment process for waste foundry sand |
| CN117123729A (en) * | 2023-07-06 | 2023-11-28 | 江门市新会区金昌矽砂有限公司 | Regeneration preparation process of baozhu sand |
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| CH575262A5 (en) * | 1974-09-12 | 1976-05-14 | Escher Wyss Ag | Reclaiming foundry moulding sand - using chamber contg. fluidised bed, pneumatic accelerator, and impact wall |
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| CN110586855A (en) * | 2019-08-07 | 2019-12-20 | 山西永益铸管股份有限公司 | Method for recycling waste sand from sand mold casting |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114101577A (en) * | 2021-11-24 | 2022-03-01 | 北京仁创砂业铸造材料有限公司 | Regeneration method of casting 3D printing waste sand |
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| CN117123729A (en) * | 2023-07-06 | 2023-11-28 | 江门市新会区金昌矽砂有限公司 | Regeneration preparation process of baozhu sand |
| CN117123729B (en) * | 2023-07-06 | 2024-05-24 | 江门市新会区金昌矽砂有限公司 | Regeneration preparation process of baozhu sand |
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Application publication date: 20200728 |