Radiation-proof foamed ceramic and preparation process thereof

Abstract

The present application relates to the technical field of foamed ceramics, and particularly relates to a radiation-proof foamed ceramic and a preparation process thereof. The radiation-proof foamed ceramic comprises the following raw materials in parts by weight: 20-50 parts of silico-alumina inorganic refractory, 15-50 parts of lead powder, 20-60 parts of barren waste, 0-15 parts of sand, 0-5 parts of calcined talc or magnesia soil; the radiation-proof foamed ceramic further comprises 0.12-0.15 parts by weight of a foaming agent and 0.1-0.35 parts by weight of high-viscosity sodium carboxymethyl cellulose, based on the total amount of the raw materials of the radiation-proof foamed ceramic. By adjusting the basic formula, the alkali metal oxide flux is reduced as much as possible, the lead powder and the alkaline earth metal are mainly used to act together, the silico-alumina inorganic refractory, the magnesia soil or the talc is introduced, and the foamed ceramic has good foaming effect under the condition of a large amount of lead. Meanwhile, a special firing system is set, the time of the high-temperature holding section in the firing system is strictly controlled, the holes formed after foaming are prevented from collapsing, the deformation is prevented, and the density and the strength of the finished product of the radiation-proof foamed ceramic are suitable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foamed ceramics, in particular to a kind of radiation-proof foamed ceramics and its preparation process. BACKGROUND

[0002] The formula system used in the production of foamed ceramics by stacking method is mostly alkali metal and alkali earth metal as flux type material, and silicate with silicon and aluminum as main components to form eutectic body for solid phase reaction, and the foamed ceramics fired is mainly used for building partition wall, waterproof material, heat and sound insulation material, mostly used in building materials, and has not been fully used in some specific functional application fields.

[0003] In the field of radiation protection, ceramic materials can also play a role, such as: rare earth element doped YSZ ceramic material, such as gadolinium oxide, tantalum oxide, etc.; zirconate system ceramic material; La site doped rare earth element modified La2Zr2O7 ceramic material.

[0004] Boron tungsten compound ceramic material, among them, element B10 in boron tungsten binary compound has a large thermal neutron absorption cross section, so the material containing B10 can capture a large number of thermal neutrons and retain a large amount of gas generated to prevent the swelling of the control assembly, and element W also has good radiation protection performance, not only has the effect of slowing down neutrons, but also has good shielding effect on X-rays. According to the present stage research and the consultation of boron tungsten binary phase diagram, it can be known that the existing boron tungsten binary compounds mainly exist in the form of W2B, WB, WB2, W2B5, WB4, etc.; MAX phase ceramic material, such as Ti3SiC2 in MAX system.

[0005] There is also a radiation-proof ceramic material with barium sulfate (BaSO4) as the main component, which has stable chemical properties and no toxicity. Among them, barium element is a heavy metal element, which has good shielding effect on X-rays. The barite powder can block harmful rays when made into a plate. At present, barite is mostly used as a radiation-proof material for concrete filler, and can also be cast into resin plate. There are few studies on the use of barite to fire ceramic plates. When the thickness of the plate is 10mm, the lead equivalent value is 0.96mmPb, which has good protective shielding effect on X-rays.

[0006] Fluorite-based radiation-resistant ceramic is made on the basis of fluorite (fluorite). Fluorite can successfully resist the damage, cracking and swelling of many materials under the action of radioactivity, which will lead to the decrease of the strength and the deterioration of the waterproof performance of these materials. Fluorite has strong radiation resistance due to the "flexible" molecular arrangement in its crystal lattice. Tungsten oxide ceramic has high strength, high density and good radiation resistance, and can be hardened by reducing grain size and increasing dislocation density to further improve radiation resistance.

[0007] The packaging anti-radiation reinforced ceramic, the high-temperature co-fired ceramic process can co-fire the tungsten slurry and the green ceramic belt into a multilayer ceramic plate with shielding function, the shielding function is equivalent to tungsten copper, but the density is smaller, which can effectively reduce the overall weight of the product, for example, a ceramic shell includes a ceramic shell body composed of five layers of alumina ceramic layers, one layer of alumina ceramic layer is added to the upper and lower surfaces respectively, and the upper surface of each alumina ceramic layer is provided with a line for wiring and a pattern for radiation shielding printed by using a metallized slurry, compared with the conventional ceramic shell, the radiation shielding effect of the total dose of space ionization is improved by more than 10 times (such as patent CN102361023A).

[0008] However, there is little research on foamed ceramics with radiation protection function, and lead, as an important radiation protection material, has not been introduced into the ceramic field. Generally, the addition amount of lead is more than 10% to have a relatively obvious radiation protection effect. Especially in the preparation of related products in the formulation system of foamed ceramics, the larger the addition amount of lead, the better the radiation protection effect. However, a large amount of lead-containing raw materials cannot be directly added to the conventional foamed ceramic formulation system to prepare foamed ceramic products with good foaming effect, and a large amount of melt is often formed and cannot be foamed. SUMMARY

[0009] The main purpose of the present application is to provide a kind of anti-radiation foamed ceramic and its preparation process, to improve the technical problem that the existing lead-containing anti-radiation foamed ceramic cannot be foamed when the addition amount of lead is large.

[0010] To achieve the above purpose, the present application provides an anti-radiation foamed ceramic, which comprises the following raw materials by weight: 20-50 parts of silico-alumina inorganic refractory material, 15-50 parts of lead powder, 20-60 parts of refractory waste, 0-15 parts of sand, and 0-5 parts of calcined talc or magnesia.

[0011] The anti-radiation foamed ceramic further comprises 0.12-0.15 parts by weight of a foaming agent and 0.1-0.35 parts by weight of a high-viscosity sodium carboxymethyl cellulose, based on the total amount of the raw materials of the anti-radiation foamed ceramic.

[0012] The present application provides a closed-pore anti-radiation foamed ceramic using lead powder as one of the main raw materials, which abandons the traditional foamed ceramic formulation system using alkali metal oxides (potassium, sodium) as the main flux, and uses lead powder and alkaline earth metals to prepare lightweight porous anti-radiation foamed ceramic materials.

[0013] The lead content in the raw materials of the radiation-proof foamed ceramic of the present solution can be more than 15%, and can even be added to about 50% at the maximum, and the higher the lead content, the better the radiation-proof effect. One of the core focuses of the present solution is the adjustment of the basic formula, using the above-mentioned raw materials and proportions, and reducing the alkali metal oxide flux in the formula as much as possible, the total amount of alkali metal oxide ≤1.0%, in addition to the lead-containing raw materials, the main raw materials also include silico-alumina inorganic refractory (such as cordierite, etc.), and a small amount of magnesia soil or talc is introduced, which can ensure that the foamed ceramic has good foaming effect under the condition of high lead content.

[0014] Because aluminum and a large amount of lead are introduced into the formula, the density is large, and segregation and precipitation are easy to occur during the ball milling production of the slurry, therefore, high-viscosity sodium carboxymethyl cellulose needs to be introduced into the raw materials to improve the viscosity of the slurry. The foaming agent and high-viscosity sodium carboxymethyl cellulose are introduced in the form of addition, that is, the total amount of the raw materials of the radiation-proof foamed ceramic refers to the total amount of the silico-alumina inorganic refractory, lead powder, refractory waste, sand, calcined talc or magnesia soil.

[0015] Preferably, the total amount of alkali metal oxide in the radiation-proof foamed ceramic raw materials is ≤1% in mass percentage. When a large amount of alkali metal is contained in the formula system, the alkali metal, lead powder and alkaline earth metal jointly act after the sintering temperature of the powder is sharply reduced, which leads to the generation of a large amount of liquid phase, the viscosity reaches the viscosity of glass, and after cooling, a color close to turquoise green and an unconventional foamed ceramic morphology appear, and at the same time, the obtained foamed ceramic will have a serious collapse.

[0016] Preferably, the refractory waste is at least one of construction debris, kaolin tailings and feldspar tailings (the tailings have a low content of potassium and sodium). The refractory waste in the present solution can use kaolin tailings, construction debris or feldspar tailings, which have a low content of alkali metal components (such as potassium and sodium) and mainly contain some alkaline earth metal components (such as calcium and magnesium).

[0017] Preferably, the silico-alumina inorganic refractory is at least one of cordierite, bauxite and corundum. One of the main functions of the silico-alumina inorganic refractory is to improve the high-temperature resistance and prevent the foamed ceramic from collapsing during sintering. The silico-alumina inorganic refractory in the present solution can use materials with a high content of aluminum, such as cordierite, bauxite, corundum powder (alumina powder) and the like, and the cordierite is most preferred.

[0018] Preferably, the radiation-proof foamed ceramic further comprises 0.3 parts by weight of a green body reinforcing agent and 1.2 parts by weight of a de-bonding agent, based on the total amount of the raw materials of the radiation-proof foamed ceramic. In addition to the above-mentioned main raw materials, the radiation-proof foamed ceramic of the present application further introduces a green body reinforcing agent to improve the plasticity of the powder particles, to improve the green strength of the foamed ceramic, to improve the bonding performance of the powder, and to reduce the breakage of the green body during transportation and production. The green body reinforcing agent that can be used in the present application includes sodium humate, various starches, carboxymethyl cellulose, polyvinyl alcohol, paraffin, bone glue, and sometimes building material fiber waste liquid or papermaking mud waste liquid, and lignin. The de-bonding agent used in the present application is a liquid de-bonding agent, such as water glass or a mixture of water glass and sodium tripolyphosphate, sodium hexametaphosphate, water glass, or NSA type de-bonding agent (Na2O-SiO2-Al2O3 salt). The addition of the above-mentioned de-bonding agent has a great influence on the slurry prepared after ball milling, which can make the viscosity of the foamed ceramic slurry after ball milling suitable, reduce the water content of the slurry, improve the fluidity of the slurry, and make the performance of the finally prepared radiation-proof foamed ceramic product better.

[0019] Preferably, the foaming agent is silicon carbide. Of course, in the remaining schemes, the foaming agent can also be used in combination with manganese oxide and the like.

[0020] Preferably, the high-viscosity sodium carboxymethyl cellulose has a viscosity of 200-1200 mPa·s. The high-viscosity sodium carboxymethyl cellulose is mainly used to improve the viscosity of the slurry after ball milling, but its viscosity also needs to be controlled within the above-mentioned suitable range, otherwise, the powder obtained after spray granulation will have poor size distribution, or even cannot form complete spherical particles, which will result in poor strength of the radiation-proof foamed ceramic product.

[0021] In addition, the present application also provides a preparation process of the radiation-proof foamed ceramic as described in any one of the above schemes, which comprises the following steps: uniformly mixing the silico-alumina inorganic refractory material, the lead powder, the barren waste material, the sand, the calcined talc or the magnesia soil, the foaming agent, and the high-viscosity sodium carboxymethyl cellulose according to the proportions, then ball milling, granulating, distributing, sintering, and cooling to obtain the radiation-proof foamed ceramic.

[0022] Preferably, the firing curve during firing is: heating from room temperature to 650 DEG C at a rate of 5.5-6.5 DEG C / min, and keeping at 650 DEG C for 30 min; heating from 650 DEG C to 950 DEG C at a rate of 3-4 DEG C / min; heating from 950 DEG C to 1070 DEG C at a rate of 5.5-6.5 DEG C / min; heating from 1070 DEG C to 1120 DEG C at a rate of 1.5-2.0 DEG C / min, and keeping at 1120 DEG C for 3-8 min. The radiation-proof foamed ceramic of the present scheme needs to strictly control the high-temperature holding time in the firing system during firing. If the holding time is too long, the holes are prone to collapse, resulting in serious deformation of the foamed ceramic product. If the holding time is too short, the density of the foamed ceramic product is prone to be too large, and the foaming effect is not good. The highest firing temperature should be controlled at 1120 DEG C, and the holding time at the highest firing temperature should be 3-8 min. The obtained radiation-proof foamed ceramic product has good quality, uniform pore size, and appropriate density and strength.

[0023] Preferably, the radiation-proof foamed ceramic after firing contains a plurality of pores, and the pore size of the pores is 0.5-2 mm. The radiation-proof foamed ceramic has a large number of pores inside. When the raw materials or the preparation process is adjusted, the density of the product can be adjusted in the range of 600-1050 kg / m 3 around, the pores are uniform, and the pore size is about 0.5-2 mm. Under the same density, the pore size of the radiation-proof foamed ceramic of the present scheme is larger than that of the conventional foamed ceramic.

[0024] Compared with the prior art, the radiation-proof foamed ceramic of the present scheme has the following beneficial effects:

[0025] 1. By adjusting the basic formula, the amount of alkali metal oxide flux is reduced as much as possible, lead powder and alkaline earth metals are mainly used together, silico-alumina inorganic refractory and a small amount of magnesia or talc are introduced, which can ensure that the foamed ceramic has good foaming effect even when the lead content is large, and the maximum lead content can be more than 50%, and the foamed ceramic prepared has uniform pores and relatively good strength.

[0026] 2. A special firing system is provided for the radiation-proof foamed ceramic, and the high-temperature holding time in the firing system is strictly controlled to avoid the collapse of the holes formed after foaming, prevent the deformation of the foamed ceramic product, and obtain a foamed ceramic product with appropriate density and strength. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0028] Figure 1 Physical map of a set of radiation-proof foamed ceramics provided by the present application;

[0029] Figure 2 Physical map of another set of radiation-proof foamed ceramics provided by the present application;

[0030] Figure 3 Physical map of a conventional radiation-proof foamed ceramic after foaming collapse.

[0031] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the protection scope of the present application.

[0033] In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on that a person skilled in the art can realize it. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the present application.

[0034] A preparation process of a radiation-proof foamed ceramic, comprising the following steps:

[0035] According to the proportion, 20-50 parts of the silico-alumina inorganic refractory material, 15-50 parts of the lead powder, 20-60 parts of the barren waste, 0-15 parts of the high-temperature sand, 0-5 parts of the calcined talc or the magnesia soil, 0.12-0.15 parts of the foaming agent, 0.1-0.35 parts of the high-viscosity sodium carboxymethyl cellulose, 0.15-0.35 parts of the green body reinforcing agent and 0.8-1.5 parts of the de-gluing agent are uniformly mixed and then ball-milled. After granulation, distribution, sintering and natural cooling, the radiation-proof foamed ceramic is obtained.

[0036] The firing curve during firing is: increasing the temperature from room temperature to 650 DEG C at a rate of 5.5-6.5 DEG C / min, and keeping the temperature at 650 DEG C for 30 min; increasing the temperature from 650 DEG C to 950 DEG C at a rate of 3-4 DEG C / min; increasing the temperature from 950 DEG C to 1070 DEG C at a rate of 5.5-6.5 DEG C / min; increasing the temperature from 1070 DEG C to 1120 DEG C at a rate of 1.5-2.0 DEG C / min, and keeping the temperature at 1120 DEG C for 3-8 min.

[0037] The barren waste is at least one of construction debris, kaolin tailings, feldspar tailings; the silico-alumina inorganic refractory material is at least one of cordierite, bauxite, corundum; the foaming agent is silicon carbide; the viscosity of the high-viscosity sodium carboxymethyl cellulose is 200-1200 mPa·s.

[0038] The technical solutions of the present application are further described in detail below in combination with specific embodiments, and it should be understood that the following embodiments are only used to explain the present application and do not limit the present application.

[0039] The chemical compositions of the raw materials in the following examples are shown in the following table (unit, %):

[0040]

[0041]

[0042] Comparative Example 1

[0043] In the conventional foamed ceramic raw material in the prior art, lead powder is directly introduced: 20 parts of lead powder, 56 parts of pressed mud (lithium tailings), 15 parts of white cutting slag, 1 part of cordierite, 8 parts of magnesia, 0.35 parts of silicon carbide, 1.3 parts of liquid debonding agent, and 0.1 part of manganese oxide are uniformly mixed and then ball milled, and then granulated, distributed, fired, and cooled to obtain a lead-containing (radiation-proof) foamed ceramic. The chemical composition corresponding to the above formula is: PbO 20.00%, SiO2 55.71%, Al2O3 13.47%, Fe2O3 0.51%, TiO2 0.06%, CaO 0.94%, MgO 2.21%, K2O 2.13%, Na2O 2.99%, and L.O.I 1.98% by mass percentage.

[0044] The traditional firing system of foamed ceramic is used: increasing the temperature from room temperature to 600 DEG C at a rate of 12 DEG C / min; increasing the temperature from 600 DEG C to 850 DEG C at a rate of 6 DEG C / min; increasing the temperature from 850 DEG C to 1000 DEG C at a rate of 5 DEG C / min; increasing the temperature from 1000 DEG C to 1160 DEG C at a rate of 3.5 DEG C / min, and keeping the temperature at 1160 DEG C for 25 min.

[0045] Comparative Example 2

[0046] The steps and parameters in the present comparative example are the same as those in Comparative Example 1, except that the firing system of the present scheme is used: the temperature is raised from room temperature to 650℃ at a rate of 6℃ / min, and the temperature is kept at 650℃ for 30min; the temperature is raised from 650℃ to 950℃ at a rate of 3.5℃ / min; the temperature is raised from 950℃ to 1070℃ at a rate of 6℃ / min; the temperature is raised from 1070℃ to 1120℃ at a rate of 1.5℃ / min, and the temperature is kept at 1120℃ for 6min.

[0047] Example 1

[0048] A preparation process of a radiation-proof foamed ceramic, comprising the following steps:

[0049] According to the proportion, 20 parts by weight of the silico-alumina inorganic refractory material (bauxite), 20 parts by weight of the lead powder, 60 parts by weight of the barren waste (50 parts of construction waste, 10 parts of kaolin tailings), 0.15 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (viscosity 1000mPa·s), 0.3 parts by weight of the green body reinforcing agent and 1.2 parts by weight of the de-gluing agent are uniformly mixed and then ball milled, and then granulated, distributed, fired and cooled to obtain the radiation-proof foamed ceramic. The chemical composition corresponding to the above formula is: PbO 20.00%, SiO2 44.8%, Al2O3 25.26%, Fe2O3 3.06%, TiO2 0.59%, CaO 0.58%, MgO 1.65%, K2O 0.34%, Na2O 0.44% and L.O.I 3.28% by mass percentage.

[0050] The conventional firing system is used: the temperature is raised from room temperature to 600℃ at a rate of 12℃ / min; the temperature is raised from 600℃ to 850℃ at a rate of 6℃ / min; the temperature is raised from 850℃ to 1000℃ at a rate of 5℃ / min; the temperature is raised from 1000℃ to 1120℃ at a rate of 3.5℃ / min, and the temperature is kept at 1120℃ for 5min.

[0051] Example 2

[0052] A preparation process of a radiation-proof foamed ceramic, comprising the following steps:

[0053] The radiation-proof foamed ceramic is obtained by mixing 25 parts by weight of the silico-alumina inorganic refractory material (corundum powder), 20 parts by weight of the lead powder, 55 parts by weight of the refractory waste (construction debris), 0.12 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000 mPa·s), 0.3 parts by weight of the green body reinforcing agent and 1.2 parts by weight of the de-bonding agent, uniformly mixing, ball milling, granulating, distributing, sintering and cooling. The chemical composition corresponding to the above formula is, in percentage by mass: PbO 20.00%, SiO2 42.49%, Al2O3 27.30%, Fe2O3 3.33%, TiO2 0.59%, CaO 0.70%, MgO 1.96%, K2O 0.33%, Na2O 0.45% and L.O.I 2.85%.

[0054] The traditional sintering system is adopted: the temperature is raised from room temperature to 600℃ at a rate of 11℃ / min; the temperature is raised from 600℃ to 850℃ at a rate of 7℃ / min; the temperature is raised from 850℃ to 1000℃ at a rate of 6℃ / min; the temperature is raised from 1000℃ to 1120℃ at a rate of 1℃ / min, and the temperature is kept at 1120℃ for 8 min.

[0055] Example 3

[0056] A preparation process of a radiation-proof foamed ceramic, comprising the following steps:

[0057] The radiation-proof foamed ceramic is obtained by mixing 30 parts by weight of the silico-alumina inorganic refractory material (bauxite), 15 parts by weight of the lead powder, 50 parts by weight of the refractory waste (construction debris), 2 parts by weight of the high-temperature sand, 3 parts by weight of the calcined talc, 0.14 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000 mPa·s), 0.3 parts by weight of the green body reinforcing agent and 1.2 parts by weight of the de-bonding agent, uniformly mixing, ball milling, granulating, distributing, sintering and cooling. The chemical composition corresponding to the above formula is, in percentage by mass: PbO 15.00%, SiO2 42.98%, Al2O3 30.42%, Fe2O3 3.23%, TiO2 0.61%, CaO 0.88%, MgO 3.26%, K2O 0.36%, Na2O 0.35% and L.O.I 2.91%.

[0058] The traditional sintering system is adopted: the temperature is raised from room temperature to 600℃ at a rate of 14℃ / min; the temperature is raised from 600℃ to 850℃ at a rate of 7℃ / min; the temperature is raised from 850℃ to 1000℃ at a rate of 4℃ / min; the temperature is raised from 1000℃ to 1120℃ at a rate of 3℃ / min, and the temperature is kept at 1120℃ for 5 min.

[0059] Example 4

[0060] A preparation process of a radiation-proof foamed ceramic, comprising the following steps:

[0061] According to the proportion, 30 parts of the silico-alumina inorganic refractory material (cordierite), 30 parts of the lead powder, 40 parts of the barren waste (construction debris), 0.12 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000 mPa·s), 0.3 parts by weight of the green body reinforcing agent, and 1.2 parts by weight of the de-bonding agent are uniformly mixed and then ball-milled, and then granulated, distributed, sintered, and cooled to obtain the radiation-proof foamed ceramic. The chemical composition corresponding to the above formula is, in terms of mass percentage: PbO 30.00%, SiO2 44.21%, Al2O3 17.75%, Fe2O3 2.42%, TiO2 0.52%, CaO 0.49%, MgO 1.81%, K2O 0.28%, Na2O 0.46%, and L.O.I 2.06%.

[0062] The conventional sintering system is adopted: the temperature is increased from room temperature to 600℃ at a rate of 12℃ / min; the temperature is increased from 600℃ to 850℃ at a rate of 6℃ / min; the temperature is increased from 850℃ to 1000℃ at a rate of 5℃ / min; the temperature is increased from 1000℃ to 1115℃ at a rate of 2℃ / min, and the temperature is kept at 1115℃ for 5 min.

[0063] The (radiation-proof) foamed ceramic prepared in Examples 1-4 and Comparative Examples 1-2 is subjected to performance testing, and the specific test results are shown in the following table:

[0064] Flexural strength / Mpa Pore size / mm Density (Kg / m 3 )]]> Acceptable product rate / % Comparative Example 1 / / / 0 Comparative Example 2 / / / 0 Example 1 5.5 ≤1 723 80 Example 2 5.8 0.5-1 747 85 Example 3 4.9 ≤1 629 75 Example 4 7.6 1-2 993 90

[0065] Note: The above qualified product rate refers to that 100 pieces of foamed ceramic products are prepared according to the preparation process of the comparative example or the example, whether they collapse or not is observed, and those that do not collapse are recorded as qualified, and those that collapse are recorded as unqualified. The qualified product rate = (qualified piece number / total piece number) × 100%.

[0066] As can be seen from the test results in the above table, in Comparative Example 1, a large amount of lead powder is directly introduced into the conventional foamed ceramic formula, which cannot be foamed and formed, and the conventional foamed ceramic sintering system is adopted, and the holding time at the highest sintering temperature is too long, which further affects the quality of the foamed ceramic finished product, and therefore, the qualified product rate is very low. When the sintering system of the present scheme is replaced in Comparative Example 2, a large amount of lead powder is directly introduced into the conventional foamed ceramic formula, and a large amount of liquid phase is generated during sintering, and therefore, a good foamed ceramic qualified product cannot be formed.

[0067] As shown in Examples 1-3, even if the radiation-proof foamed ceramic formulation in the present solution adopts the conventional foamed ceramic firing system, the radiation-proof foamed ceramic produced still has a large number of qualified products, and the radiation-proof foamed ceramic finished product can be produced, and the qualified product rate of some formulations can even be increased to 90%. With the increase of the amount of lead powder, the firing temperature decreases, the bulk density increases, the content of lead increases under the condition of the same pore size, the density increases, and the radiation-proof performance also improves.

[0068] Example 5

[0069] In the present comparative example, the steps and parameters are the same as those in Example 1, except that the firing system in the present solution is used: the temperature is increased from room temperature to 650°C at a rate of 6.2°C / min, and the temperature is kept at 650°C for 30 min; the temperature is increased from 650°C to 950°C at a rate of 3.75°C / min; the temperature is increased from 950°C to 1070°C at a rate of 6°C / min; the temperature is increased from 1070°C to 1120°C at a rate of 1.67°C / min, and the temperature is kept at 1120°C for 5 min.

[0070] Example 6

[0071] In the present comparative example, the steps and parameters are the same as those in Example 2, except that the firing system in the present solution is used: the temperature is increased from room temperature to 650°C at a rate of 6°C / min, and the temperature is kept at 650°C for 30 min; the temperature is increased from 650°C to 950°C at a rate of 3.5°C / min; the temperature is increased from 950°C to 1070°C at a rate of 6°C / min; the temperature is increased from 1070°C to 1120°C at a rate of 1.6°C / min, and the temperature is kept at 1120°C for 5 min. At the same time, the amount of lead powder is increased to 30 parts, and the amount of construction waste is reduced to 45 parts, and the formulation is as follows: 25 parts by weight of the silico-alumina inorganic refractory material (corundum powder), 30 parts by weight of the lead powder, 45 parts by weight of the refractory waste (construction waste), 0.12 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000 mPa·s), 0.3 parts by weight of the green body reinforcing agent, and 1.2 parts by weight of the de-gluing agent. In terms of mass percentage, the chemical composition corresponding to the above formulation is: PbO 30.00%, SiO2 32.22%, Al2O3 32.34%, Fe2O3 2.37%, TiO2 0.32%, CaO 0.02%, MgO 0.38%, K2O 0.14%, Na2O 0.27%, and L.O.I 1.94%.

[0072] Example 7

[0073] The steps and parameters in the present comparative example are the same as those in Example 3, except that the firing schedule of the present scheme is used: the temperature is raised from room temperature to 650℃ at a rate of 6.3℃ / min, and the temperature is kept at 650℃ for 30min; the temperature is raised from 650℃ to 950℃ at a rate of 3.7℃ / min; the temperature is raised from 950℃ to 1070℃ at a rate of 5.8℃ / min; the temperature is raised from 1070℃ to 1120℃ at a rate of 1.8℃ / min, and the temperature is kept at 1120℃ for 5min. Meanwhile, the amount of lead powder is increased to 25 parts, and the amount of construction waste is reduced to 40 parts, i.e. 30 parts by weight of the silico-alumina inorganic refractory material (bauxite), 25 parts by weight of the lead powder, 40 parts by weight of the refractory waste (construction waste), 2 parts by weight of the high-temperature sand, 3 parts by weight of the calcined talc, 0.14 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000mPa·s), 0.3 parts by weight of the green body reinforcing agent, and 1.2 parts by weight of the de-binding agent. In terms of mass percentage, the chemical composition corresponding to the above formulation is: PbO 25.00%, SiO2 35.89%, Al2O3 28.70%, Fe2O3 2.70%, TiO2 0.54%, CaO 0.88%, MgO 3.07%, K2O 0.32%, Na2O 0.4%, and L.O.I 2.5%.

[0074] Example 8

[0075] The steps and parameters in the present comparative example are the same as those in Example 4, except that the firing schedule of the present scheme is used: the temperature is raised from room temperature to 650℃ at a rate of 5.9℃ / min, and the temperature is kept at 650℃ for 30min; the temperature is raised from 650℃ to 950℃ at a rate of 3.7℃ / min; the temperature is raised from 950℃ to 1070℃ at a rate of 6℃ / min; the temperature is raised from 1070℃ to 1120℃ at a rate of 1.7℃ / min, and the temperature is kept at 1120℃ for 5min.

[0076] The radiation-proof foamed ceramics prepared in Examples 5-8 are subjected to performance detection, and the specific detection results are shown in the following table:

[0077] Flexural strength / Mpa Pore size / mm Density (Kg / m 3 )]]> Acceptable product rate / % Example 5 6.0 0.5-1 733 85 Example 6 6.33 0.5-1 863 85 Example 7 5.38 ≤1 655 80 Example 8 8.0 0.5-1 1050 95

[0078] As can be seen from the test results in the above table, the qualified product rate of the radiation-proof foamed ceramics prepared by using the firing schedule of the present scheme is further improved, the bending strength can be improved to more than 6Mpa, and the pores are uniform, the density is between 730-1100Kg / m 3 , and the qualified product rate is high. Moreover, when the firing schedule of the present scheme is used, the amount of lead powder can be increased to 25-40 parts, and the product prepared even when the amount of lead powder is increased still has a high qualified product rate.

[0079] Example 9

[0080] The steps and parameters in this example are the same as those in Example 5, except that the silice-alumina inorganic refractory is cordierite.

[0081] The formulation is as follows: 20 parts by weight of the silice-alumina inorganic refractory (cordierite), 20 parts by weight of the lead powder, 60 parts by weight of the barren waste (50 parts of construction debris, 10 parts of kaolin tailings), 0.15 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (viscosity 1000 mPa-s), 0.3 parts by weight of the body strengthening agent, and 1.2 parts by weight of the de-binding agent; the corresponding chemical composition of the above formulation in terms of mass percentage is: PbO 20.00%, SiO2 52.57%, Al2O3 18.24%, Fe2O3 2.93%, TiO2 0.59%, CaO 0.34%, MgO 1.43%, K2O 0.32%, Na2O 0.5%, and L.O.I 3.08%.

[0082] The firing schedule is as follows: from room temperature to 650°C at a rate of 6.2°C / min, and holding at 650°C for 30 min; from 650°C to 950°C at a rate of 3.75°C / min; from 950°C to 1070°C at a rate of 6°C / min; from 1070°C to 1120°C at a rate of 1.67°C / min, and holding at 1120°C for 5 min.

[0083] Example 10

[0084] The steps and parameters in this example are the same as those in Example 6, except that the silice-alumina inorganic refractory is cordierite.

[0085] The firing schedule is as follows: from room temperature to 650°C at a rate of 6.2°C / min, and holding at 650°C for 30 min; from 650°C to 950°C at a rate of 3.75°C / min; from 950°C to 1070°C at a rate of 6°C / min; from 1070°C to 1120°C at a rate of 1.67°C / min, and holding at 1120°C for 5 min.

[0086] Meanwhile, the amount of lead powder is increased to 45 parts, i.e. the formulation is as follows: 20 parts by weight of the silice-alumina inorganic refractory (cordierite), 45 parts by weight of the lead powder, 35 parts by weight of the inert waste (construction debris), 0.12 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000 mPa·s), 0.3 parts by weight of the green strength enhancer, and 1.2 parts by weight of the de-bonding agent. In terms of mass percentage, the chemical composition corresponding to the above formulation is: PbO 45.00%, SiO2 35.38%, Al2O3 13.27%, Fe2O3 2.05%, TiO2 0.4%, CaO 0.33%, MgO 1.28%, K2O 0.21%, Na2O 0.36%, and L.O.I 1.72%.

[0087] Example 11

[0088] In this example, the steps and parameters are the same as in Example 7, except that the silice-alumina inorganic refractory is cordierite.

[0089] The firing schedule is as follows: from room temperature to 650°C at a rate of 6.2°C / min, and holding at 650°C for 30 min; from 650°C to 950°C at a rate of 3.75°C / min; from 950°C to 1070°C at a rate of 6°C / min; from 1070°C to 1120°C at a rate of 1.67°C / min, and holding at 1120°C for 5 min.

[0090] Meanwhile, the amount of lead powder is increased to 50 parts, i.e. 25 parts by weight of the silice-alumina inorganic refractory (cordierite), 50 parts by weight of the lead powder, 20 parts by weight of the inert waste (construction debris), 2 parts by weight of the high-temperature sand, 3 parts by weight of the calcined talc, 0.14 parts by weight of the foaming agent (silicon carbide), 0.25 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000 mPa·s), 0.3 parts by weight of the green strength enhancer, and 1.2 parts by weight of the de-bonding agent. In terms of mass percentage, the chemical composition corresponding to the above formulation is: PbO 50.00%, SiO2 30.72%, Al2O3 12.89%, Fe2O3 1.41%, TiO2 0.35%, CaO 0.44%, MgO 2.33%, K2O 0.2%, Na2O 0.32%, and L.O.I 1.34%.

[0091] The radiation-proof foamed ceramic prepared in Examples 9-11 is subjected to performance testing, and the specific test results are shown in the following table.

[0092] Flexural strength / Mpa Pore size / mm Density (Kg / m 3 )]]> Acceptable product rate / % Example 9 6.2 0.5-1 745 90 Example 10 6.5 ≤1 788 85 Example 11 6.6 ≤1 800 85

[0093] From the test results of the above table, it can be seen that after replacing the silice-alumina inorganic refractory material with the preferred cordierite, the bending strength of the radiation-proof foamed ceramic in the present scheme can be further improved. In addition, the addition amount of lead powder can be increased to more than 40 parts, and the highest addition amount can even reach 50 parts. The prepared radiation-proof foamed ceramic product still has a relatively high qualified product rate and relatively good performance.

[0094] Example 12

[0095] A preparation process of a radiation-proof foamed ceramic, comprising the following steps:

[0096] According to the proportion, 30 parts by weight of the silice-alumina inorganic refractory material (cordierite), 35 parts by weight of the lead powder, 35 parts by weight of the barren waste (25 parts of construction waste and 10 parts of kaolin tailings), 0.12 parts by weight of the foaming agent (silicon carbide), 0.3 parts by weight of the high-viscosity sodium carboxymethyl cellulose (1000 mPa·s), 0.3 parts by weight of the body strengthening agent and 1.2 parts by weight of the de-gluing agent are uniformly mixed and then ball milled. After granulation, distribution, sintering and cooling, the radiation-proof foamed ceramic is obtained. The chemical composition corresponding to the above formula is: PbO 35.00%, SiO2 40.12%, Al2O3 17.56%, Fe2O3 1.74%, TiO2 0.49%, CaO 0.49%, MgO 1.71%, K2O 0.28%, Na2O 0.41% and L.O.I 2.2% by mass percent.

[0097] The sintering curve during sintering is: from room temperature to 650℃ at a rate of 6.2℃ / min, and keep at 650℃ for 30min; from 650℃ to 950℃ at a rate of 3.75℃ / min; from 950℃ to 1070℃ at a rate of 6℃ / min; from 1070℃ to 1120℃ at a rate of 1.67℃ / min, and keep at 1120℃ for 5min.

[0098] The radiation-proof foamed ceramic prepared in Example 12 is subjected to performance detection, and the specific detection results are shown in the following table:

[0099] Flexural strength / Mpa Pore size / mm Density (Kg / m 3 )]]> Acceptable product rate / % Example 12 8.9 ≤0.5 1050 95

[0100] From the test results of the above table, it can be seen that under the most preferred raw materials and parameters, the bending strength of the radiation-proof foamed ceramic prepared in the present scheme can reach 8.9Mpa, the qualified product rate is about 95%, and the overall performance is relatively good.

[0101] The above merely describes the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structural variations or direct / indirect applications in other related technical fields based on the content of the present application description are included in the patent protection scope of the present application.

Claims

1. A radiation-resistant foamed ceramic, characterized in that, The raw materials include the following parts by weight: 20-50 parts of silica-alumina inorganic refractory material, 15-50 parts of lead powder, 20-60 parts of barren waste, 0-15 parts of sand, and 0-5 parts of calcined talc or magnesia clay. Based on the total amount of raw materials in the radiation-proof foamed ceramic, the radiation-proof foamed ceramic further includes 0.12-0.15 parts by weight of foaming agent and 0.1-0.35 parts by weight of high-viscosity sodium carboxymethyl cellulose; The total amount of alkali metal oxides in the radiation-resistant foamed ceramic raw material is ≤1%; The barren waste material is at least one of construction waste, kaolin tailings, and feldspar tailings; The silica-aluminate inorganic refractory material is at least one of cordierite, bauxite, and corundum; The preparation process of the radiation-proof foamed ceramic includes the following steps: according to the formula, the silica-alumina inorganic refractory material, the lead powder, the barren waste, the sand, the calcined talc or the magnesia clay, the foaming agent and the high-viscosity sodium carboxymethyl cellulose are mixed evenly and then ball-milled, and then granulated, distributed, fired and cooled to obtain the radiation-proof foamed ceramic; The firing curve during firing is as follows: The temperature was increased from room temperature to 650℃ at a rate of 5.5-6.5℃ / min, and held at 650℃ for 30 minutes. The temperature was increased from 650℃ to 950℃ at a rate of 3-4℃ / min. The temperature was increased from 950℃ to 1070℃ at a rate of 5.5-6.5℃ / min. The temperature is increased from 1070℃ to 1120℃ at a rate of 1.5-2.0℃ / min, and then held at 1120℃ for 3-8 minutes.

2. The radiation-shielding foamed ceramic according to claim 1, characterized in that, Based on the total amount of raw materials of the radiation-proof foamed ceramic, the radiation-proof foamed ceramic further includes 0.15-0.35 parts by weight of green body reinforcing agent and 0.8-1.5 parts by weight of desizing agent.

3. The radiation-shielding foamed ceramic according to claim 1, characterized in that, The foaming agent is silicon carbide.

4. The radiation-shielding foamed ceramic according to claim 1, characterized in that, The viscosity of the high-viscosity sodium carboxymethyl cellulose is 200-1200 mPa·s.

5. A preparation process for radiation-shielding foamed ceramic as described in any one of claims 1-4, characterized in that, The process includes the following steps: according to the specified ratio, the silica-alumina inorganic refractory material, the lead powder, the barren waste, the sand, the calcined talc or the magnesia clay, the foaming agent and the high-viscosity sodium carboxymethyl cellulose are mixed evenly and then ball-milled. After granulation, spreading, firing and cooling, the radiation-proof foamed ceramic is obtained. The firing curve during firing is as follows: The temperature was increased from room temperature to 650℃ at a rate of 5.5-6.5℃ / min, and held at 650℃ for 30 minutes. The temperature was increased from 650℃ to 950℃ at a rate of 3-4℃ / min. The temperature was increased from 950℃ to 1070℃ at a rate of 5.5-6.5℃ / min. The temperature is increased from 1070℃ to 1120℃ at a rate of 1.5-2.0℃ / min, and then held at 1120℃ for 3-8 minutes.

6. The preparation process of the radiation-shielding foamed ceramic according to claim 5, characterized in that, The fired radiation-resistant foamed ceramic contains a number of pores with a pore diameter of 0.5-2 mm.

Images