Radiation shielding type high-strength ceramsite based on lead zinc ore tailings and preparation method of radiation shielding type high-strength ceramsite

Abstract

The invention discloses radiation shielding type high-strength ceramsite based on lead-zinc ore tailings and a preparation method of the radiation shielding type high-strength ceramsite, and relates to the technical field of radiation protection concrete. The lead-zinc ore tailings containing more Pb elements are used as main ceramic forming raw materials, a proper amount of lead-rich raw materials are used as auxiliary materials to adjust the content of the Pb elements, a proper amount of boron-rich raw materials are used as auxiliary materials to adjust the content of the B elements, and the composite powder with the proper content of the Pb elements and the proper content of the B elements is prepared. The efficient shielding effect of the Pb element and the B element on gamma rays and neutron radiation is fully exerted, and the sintering temperature of the ceramsite is remarkably reduced. In addition, a proper amount of fly ash floating beads with spheroidal cavity structures are introduced as a pore-forming template, so that the purpose of regulating and controlling the density grade of the ceramsite is achieved, and the problem that the concrete structure is not uniform due to the fact that the density of aggregate is not matched with that of a cementing material is solved. The prepared ceramsite has relatively high strength and a good radiation shielding coefficient, and has a density similar to that of a cementing material.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of radiation shielding concrete, and particularly relates to a radiation shielding high-strength ceramsite based on lead-zinc ore tailings and a preparation method thereof. BACKGROUND

[0002] Radiation shielding concrete is a high-quality material with good structural performance, convenient construction, low cost and radiation shielding performance, and is widely applied to fields with radiation risks such as nuclear power plants, medical buildings and nuclear research facilities. Aggregates account for more than 60% of the volume fraction in the radiation shielding concrete, and the aggregates with good radiation shielding performance are the key core raw materials of the radiation shielding concrete. At present, the radiation shielding concrete mainly uses natural mineral resources with high density such as barite, serpentine and iron ore as the aggregates, and the density difference between the aggregates and the cementing material is obvious. After the concrete is poured, the bleeding phenomenon is common, the aggregates and the cementing material are prone to stratification, the structure of the radiation shielding concrete is uneven, and the mechanical strength and the radiation shielding performance of the concrete are seriously weakened. SUMMARY

[0003] One of the purposes of the application is to provide a preparation method of radiation shielding high-strength ceramsite based on lead-zinc ore tailings, so as to solve the problem of uneven concrete structure caused by the density mismatch between the aggregates and the cementing material.

[0004] In order to solve the above technical problems, the application adopts the following technical scheme: a preparation method of radiation shielding high-strength ceramsite based on lead-zinc ore tailings, comprising the following steps:

[0005] (1) a certain amount of lead-zinc ore tailings powder is taken, a proper amount of lead-rich powder is added to control the content of lead element, and a proper amount of boron-rich powder is added to control the content of boron element, so as to serve as a main raw material;

[0006] (2) fly ash floating beads are used as a pore-forming template for adjusting the density grade of the ceramsite;

[0007] (3) the main raw material and the pore-forming template are weighed according to the proportion and then subjected to homogenization treatment to obtain uniformly dispersed composite powder;

[0008] (4) the composite powder is prepared into ceramsite raw material by using a granulator, the dried ceramsite raw material is subjected to high-temperature sintering, and after sintering, the sintered product is cooled in the furnace to obtain the radiation shielding high-strength ceramsite based on lead-zinc ore tailings.

[0009] Preferably, the lead-rich powder is one or a plurality of composite components of lead glass powder, lead smelting dust, lead storage battery production waste residue and yellow lead powder, and the particle size of the lead glass powder, the lead smelting dust, the lead storage battery production waste residue and the yellow lead powder is less than 0.045 mm.

[0010] More preferably, the boron-rich powder is one or a plurality of composite compositions of glass or borax, and the particle size of the boron glass powder or borax is less than 0.045 mm.

[0011] More preferably, the particle size of the lead-zinc mine tailings powder is less than 0.088 mm.

[0012] More preferably, the particle size of the fly ash floating bead is less than 0.088 mm.

[0013] More preferably, the mass ratio of the lead-zinc mine tailings powder in all raw materials for preparing the ceramsite raw material is not less than 60%, and the mass ratio of the fly ash floating bead in all raw materials for preparing the ceramsite raw material is not more than 15%.

[0014] More preferably, in the composite powder obtained in step (3), the mass fraction of lead element is 5-20%, and the mass fraction of boron element is not less than 1%.

[0015] More preferably, the particle size of the ceramsite raw material obtained in step (4) is between 0.5-25 mm.

[0016] More preferably, in step (4), the high-temperature sintering condition is that the temperature is 600-1200℃, the holding time is 20-60 min, and finally the furnace is cooled.

[0017] It should be noted that in some contents of the present application, chemical element symbols are directly used for expression, for example, the lead element is Pb element, and the boron element is B element, which does not affect the understanding of the present application by those skilled in the art.

[0018] The present application also provides a radiation shielding high-strength ceramsite based on lead-zinc mine tailings, which is prepared by the above preparation method.

[0019] The present application uses the lead-zinc mine tailings containing a large amount of Pb element as the main raw material for making ceramics, and adjusts the content of Pb element by adding an appropriate amount of lead-rich material, and adjusts the content of B element by adding an appropriate amount of boron-rich material, so as to prepare a composite powder with appropriate Pb element and B element content, which fully plays the high-efficiency shielding effect of Pb element and B element on gamma rays and neutron radiation, and significantly reduces the sintering temperature of the ceramsite. In addition, by introducing an appropriate amount of fly ash floating bead with a spherical cavity structure as a pore-forming template, the density grade of the ceramsite is controlled, and the problem of uneven concrete structure caused by the mismatch of the density of aggregate and cementitious material is solved.

[0020] Compared with the prior art, the lead-zinc ore tailing-based ceramite prepared by the application has high strength and good radiation shielding coefficient, and has density close to that of cementing material. In addition, the preparation process of the application is simple, the raw materials are mainly solid wastes, and the application has the advantages of low energy consumption, low carbon emission, low cost and easy industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a preparation method flowchart of the application;

[0022] Figure 2 It is a physical map of the radiation shielding high-strength ceramite based on lead-zinc ore tailings prepared by the application. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of those skilled in the art, the application will be further described below in combination with examples and drawings. The content mentioned in the embodiments is not a limitation of the application.

[0024] As Figure 1 shown, a preparation method of radiation shielding high-strength ceramite based on lead-zinc ore tailings mainly uses lead-zinc ore tailing powder containing Pb element with suitable particle size as main raw material, uses lead glass powder, lead smelting dust, lead storage battery production waste slag, and yellow lead powder and other lead-rich raw materials to adjust the content of Pb element, uses appropriate boron glass powder, borax and other boron-containing raw materials to control B element, and uses fly ash floating bead as a pore-forming template to control the density grade of ceramite. Then the above-mentioned materials are weighed, homogenized, formed, and dried to obtain ceramite raw material. The dried ceramite raw material is then sintered at high temperature to obtain radiation shielding high-strength ceramite based on lead-zinc ore tailings. In the following examples, the particle size of the lead-zinc ore tailing powder used is less than 0.088mm, and the particle size of the Pb-rich powder and the B-rich powder is less than 0.045mm, and the particle size of the fly ash floating bead is less than 0.088mm; in the raw material ratio for preparing ceramite, the mass ratio of lead-zinc ore tailing powder is not less than 60%, the mass ratio of fly ash floating bead is 1.5%-15%, the mass ratio of Pb element is 5-20%, and the mass ratio of B element is not less than 1%. The main difference between the examples is that the particle size of the lead-zinc ore tailing powder, the type of lead-rich raw material, the type of boron-rich raw material, the ratio of various raw materials, and the conditions of heat treatment are different.

[0025] Example 1

[0026] I. Preparation of ceramite raw material

[0027] Raw materials: 200-mesh lead-zinc mine tailings powder (PbO content 1.5 wt%), 600-mesh lead glass powder (PbO content 25 wt%), 600-mesh high-boron glass powder (B2O3 content 18.5 wt%), 200-mesh fly ash floating bead, paper pulp waste liquid (binder), the lead-zinc mine tailings powder in the above raw materials is from a tailings pond in Hengyang, Hunan Province, and the other raw materials are mainly enterprise solid waste or commercially available raw materials.

[0028] Equipment: planetary ball mill, disc granulator, electric heating drying oven, muffle furnace.

[0029] 1. The lead-zinc mine tailings powder, lead glass powder, boron glass powder, and fly ash floating bead were weighed according to the mass ratio of 60:21:16:3, then mixed in a planetary ball mill, the ball-to-material ratio was 1:1, the rotation speed was 300 r / min, and the processing time was 15 min, then the material was discharged to obtain a homogenized powder for standby.

[0030] 2. Start the disc granulator, first add 500 g of homogenized powder to the mixing disc, spray an appropriate amount of paper pulp waste liquid into the mixing disc, mix for 1-3 min, then appropriately supplement the paper pulp waste liquid according to the balling condition of the material; then slowly screen in the homogenized powder, and then appropriately supplement the paper pulp waste liquid; repeat the above steps, and the ceramic raw material balls in the mixing disc continuously grow, and the ceramic raw material balls with a particle size of 10-25 mm are treated by mechanical screening.

[0031] II. Heat treatment of ceramic raw material balls.

[0032] 1. Dry the ceramic raw material balls in a blast drying oven, the drying schedule is 110℃ for 24 h.

[0033] 2. Put the dried ceramic raw material balls into a sagger, then place it in a muffle furnace for heat treatment. The heat treatment schedule is as follows: room temperature-350℃, 10℃ / min; 350℃ for 1 h; 350℃-850℃, 5℃ / min; 850℃ for 0.5 h; cool down with the furnace, then mechanically screen to obtain lead-zinc mine tailings-based high-strength ceramic.

[0034] III. Performance index test.

[0035] After testing, the performance indexes of the radiation shielding type high-strength ceramic based on lead-zinc mine tailings prepared in this embodiment are as follows: apparent density 2.35 g / cm 3 , bulk density 1455 kg / m 3 , cylinder compressive strength 20.5 MPa, water absorption 3.1%, γ-ray attenuation coefficient 0.22 cm -1 , neutron ray attenuation coefficient 0.25 cm -1 .

[0036] Example 2

[0037] I. Preparation of ceramsite raw meal.

[0038] Raw materials: 200-mesh lead-zinc ore tailings powder (PbO content 1.5 wt%), 600-mesh lead smelting dust (PbO content 45 wt%), 600-mesh high borosilicate glass powder (B2O3 content 18.5 wt%), 200-mesh fly ash cenospheres, and pulp waste liquor (binder). Among the above raw materials, the lead-zinc ore tailings powder comes from a tailings pond in Hengyang, Hunan Province. The other raw materials are mainly enterprise solid waste or commercially available raw materials.

[0039] Equipment: planetary ball mill, disc granulator, electric drying oven, muffle furnace.

[0040] 1. Weigh the lead-zinc ore tailings powder, lead smelting dust, high borosilicate glass powder, and fly ash cenospheres according to a mass ratio of 65:15:15:5. Then, place them in a planetary ball mill for mixing. The ball-to-material ratio is 1:1, the rotation speed is 300 r / min, and the processing time is 15 min. The resulting homogenized powder is ready for use.

[0041] 2. Start the disc granulator. First, add 500g of homogenized powder to the mixing disc. Then, spray an appropriate amount of pulp waste liquid into the mixing disc. After mixing for 1-3 minutes, spray more pulp waste liquid as needed based on the pelletizing condition of the material. Then, slowly sieve in the homogenized powder and spray more pulp waste liquid as needed. Repeat the above steps. The ceramsite pellets in the mixing disc will continue to grow. Use mechanical screening to process the ceramsite pellets with a particle size of 5-15mm.

[0042] II. Heat treatment of ceramsite raw material balls.

[0043] 1. Use a blower-type drying oven to dry the ceramsite raw material. The drying regime is to keep it at 110℃ for 24 hours.

[0044] 2. The dried ceramsite pellets are loaded into a sagger and then placed in a muffle furnace for heat treatment. The heat treatment regime is as follows: room temperature - 350℃, 10℃ / min; 350℃ for 1 hour; 350℃ - 900℃, 5℃ / min; 900℃ for 0.5 hours; cooled in the furnace, and then mechanically screened to obtain high-strength ceramsite based on lead-zinc ore tailings.

[0045] III. Performance Index Testing.

[0046] The performance indicators of the high-strength ceramsite based on lead-zinc mine tailings prepared in this embodiment are as follows, as tested: apparent density 2.40 g / cm³. 3 Bulk density 1498 kg / m³ 3 The cylinder compressive strength is 23.5 MPa, the water absorption rate is 2.5%, and the gamma-ray attenuation coefficient is 0.26 cm⁻¹. -1The neutron radiation attenuation coefficient is 0.24 cm⁻¹. -1 .

[0047] Example 3

[0048] I. Preparation of ceramsite raw meal.

[0049] Raw materials: 325 mesh lead-zinc ore tailings powder (PbO content 1.5 wt%), 600 mesh lead smelting dust (PbO content 45 wt%), 325 mesh borax (Na2B4O7·5H2O, of which B2O3 content is 48 wt%), 325 mesh fly ash cenospheres, and pulp waste liquor (binder). Among the above raw materials, the lead-zinc ore tailings powder comes from a tailings pond in Hengyang, Hunan Province. The other raw materials are mainly enterprise solid waste or commercially available raw materials.

[0050] Equipment: planetary ball mill, disc granulator, electric drying oven, muffle furnace.

[0051] 1. Weigh the lead-zinc ore tailings powder, lead smelting dust, borax powder, and fly ash cenospheres according to a mass ratio of 70:18:7:5. Then, place them in a planetary ball mill for mixing. The ball-to-material ratio is 1:1, the rotation speed is 300 r / min, and the processing time is 15 min. The resulting homogenized powder is ready for use.

[0052] 2. Start the disc granulator. First, add 500g of homogenized powder to the mixing disc. Then, spray an appropriate amount of pulp waste liquid into the mixing disc. After mixing for 3-5 minutes, spray more pulp waste liquid as needed based on the pelletizing condition of the material. Then, slowly sieve in the homogenized powder and spray more pulp waste liquid as needed. Repeat the above steps. The ceramsite pellets in the mixing disc will continue to grow. Use mechanical screening to process the ceramsite pellets with a particle size of 10-20mm.

[0053] II. Heat treatment of ceramsite raw material balls.

[0054] 1. Use a blower-type drying oven to dry the ceramsite raw material. The drying regime is to keep it at 110℃ for 24 hours.

[0055] 2. The dried ceramsite pellets are loaded into a sagger and then placed in a muffle furnace for heat treatment. The heat treatment regime is as follows: room temperature - 350℃, 10℃ / min; 350℃ for 1 hour; 350℃ - 950℃, 5℃ / min; 950℃ for 0.5 hours; cooled in the furnace, and then mechanically screened to obtain high-strength ceramsite based on lead-zinc ore tailings.

[0056] III. Performance Index Testing.

[0057] The performance indicators of the high-strength ceramsite based on lead-zinc mine tailings prepared in this embodiment are as follows, as tested: apparent density 2.47 g / cm³. 3 Bulk density 1535 kg / m³3 The cylinder compressive strength is 20.5 MPa, the water absorption rate is 3.3%, and the gamma-ray attenuation coefficient is 0.27 cm⁻¹. -1 The neutron radiation attenuation coefficient is 0.25 cm⁻¹. -1 .

[0058] Example 4

[0059] I. Preparation of ceramsite raw meal.

[0060] Raw materials: 800 mesh lead-zinc ore tailings powder (PbO content 1.5 wt%), 325 mesh litharge powder (PbO content 99 wt%), 600 mesh high borosilicate glass powder (B2O3 content 18.5 wt%), 200 mesh fly ash cenospheres, and pulp waste liquor (binder). Among the above raw materials, the lead-zinc ore tailings powder comes from a tailings pond in Hengyang, Hunan Province. The other raw materials are mainly enterprise solid waste or commercially available raw materials.

[0061] Equipment: planetary ball mill, disc granulator, electric drying oven, muffle furnace.

[0062] 1. Weigh the lead-zinc ore tailings powder, litharge powder, high borosilicate glass powder, and fly ash cenospheres according to a mass ratio of 62:14:16:8. Then, place them in a planetary ball mill for mixing. The ball-to-material ratio is 1:1, the rotation speed is 300 r / min, and the processing time is 15 min. The resulting homogenized powder is ready for use.

[0063] 2. Start the disc granulator. First, add 500g of homogenized powder to the mixing disc. Then, spray an appropriate amount of pulp waste liquid into the mixing disc. After mixing for 3-5 minutes, spray more pulp waste liquid as needed based on the pelletizing condition of the material. Then, slowly sieve in the homogenized powder and spray more pulp waste liquid as needed. Repeat the above steps. The ceramsite pellets in the mixing disc will continue to grow. Use mechanical screening to process the ceramsite pellets with a particle size of 0.5-3mm.

[0064] II. Heat treatment of ceramsite raw material balls.

[0065] 1. Use a blower-type drying oven to dry the ceramsite raw material. The drying regime is to keep it at 110℃ for 24 hours.

[0066] 2. The dried ceramsite pellets are loaded into a sagger and then placed in a muffle furnace for heat treatment. The heat treatment regime is as follows: room temperature - 300℃, 5℃ / min; 300℃ for 2 hours; 300℃ - 1000℃, 10℃ / min; 1000℃ for 1 hour; cooled in the furnace, and then mechanically screened to obtain high-strength ceramsite based on lead-zinc ore tailings.

[0067] III. Performance Index Testing.

[0068] The performance indicators of the high-strength ceramsite based on lead-zinc mine tailings prepared in this embodiment are as follows, based on testing: apparent density 2.51 g / cm³. 3 Bulk density 1610 kg / m³ 3 The cylinder compressive strength is 25.3 MPa, the water absorption rate is 2.3%, and the gamma-ray attenuation coefficient is 0.29 cm⁻¹. -1 The neutron radiation attenuation coefficient is 0.24 cm⁻¹. -1 .

[0069] The lead-zinc mine tailings used in the above embodiments for preparing the ceramsite mainly originate from a lead-zinc mine tailings dam in Hengyang City, Hunan Province, and have a large existing stockpile. Lead glass powder, lead smelting dust, borosilicate glass powder, and fly ash cenospheres mainly originate from enterprise solid waste; pulp waste liquor is inexpensive. Overall, the raw material costs are low and the sources are wide-ranging. The prepared lead-zinc mine tailings-based ceramsite has high compressive strength, low water absorption, a density similar to cementitious materials, and good shielding performance against gamma rays and neutron rays. Simultaneously, the introduction of lead glass, benzene glass, and borax during raw material preparation can significantly reduce the sintering temperature of the ceramsite, resulting in significant energy-saving advantages.

[0070] To facilitate understanding by those skilled in the art of the improvements of this invention over the prior art, some of the accompanying drawings and descriptions have been simplified. The above embodiments are preferred implementations of this invention. In addition, this invention can be implemented in other ways. Any obvious substitutions without departing from the concept of this technical solution are within the protection scope of this invention.

Claims

1. A method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings, characterized in that, Includes the following steps: (1) Take a certain amount of lead-zinc ore tailings powder, add an appropriate amount of lead-rich powder to regulate the lead content, and add an appropriate amount of boron-rich powder to regulate the boron content, as the main raw material. (2) Fly ash cenospheres are used as pore-forming templates to control the density grade of ceramsite; (3) The main raw material and the pore-forming template are weighed according to the ratio and then homogenized to obtain a uniformly dispersed composite powder; (4) The composite powder is prepared into ceramsite raw material using a granulator, and the dried ceramsite raw material is then sintered at high temperature. After sintering, it is cooled with the furnace to obtain the radiation shielding type high-strength ceramsite based on lead-zinc mine tailings.

2. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: The lead-rich powder is composed of one or more of the following: lead glass powder, lead smelting dust, lead-acid battery production waste residue, and lead oxide powder. The particle size of the lead glass powder, lead smelting dust, lead-acid battery production waste residue, and lead oxide powder is all less than 0.045 mm.

3. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: The boron-rich powder is composed of one or more of glass and borax, and the particle size of the borosilicate glass powder and borax is less than 0.045 mm.

4. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: The particle size of the lead-zinc mine tailings powder is less than 0.088 mm.

5. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: The fly ash cenospheres have a particle size of less than 0.088 mm.

6. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: The lead-zinc mine tailings powder shall account for no less than 60% of the total mass of all raw materials used in the preparation of ceramsite raw meal; the fly ash cenospheres shall account for no more than 15% of the total mass of all raw materials used in the preparation of ceramsite raw meal.

7. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: In the composite powder obtained in step (3), the mass fraction of lead is 5-20% and the mass fraction of boron is not less than 1%.

8. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: The particle size of the ceramsite raw material obtained in step (4) is between 0.5 and 25 mm.

9. The method for preparing radiation-shielding high-strength ceramsite based on lead-zinc mine tailings according to claim 1, characterized in that: In step (4), the conditions for high-temperature sintering are: temperature of 600-1200℃, holding time of 20-60min, and finally cooling with the furnace.

10. A radiation-shielding type high-strength ceramsite based on lead-zinc mine tailings, characterized in that: It is prepared by the preparation method described in any one of claims 1-9.

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