阅读说明：本技术 一种rh高附着率喷补料及其制备方法 (RH high-adhesion-rate gunning mix and preparation method thereof ) 是由 刘孟 张剑君 万菲 彭著刚 叶途明 秦世民 于 2021-06-18 设计创作，主要内容包括：本发明公开了一种RH高附着率喷补料,其特征在于,各组分及其所占质量百分比包括：废旧镁铬砖回收料30～60％,烧结镁砂20～45％,镁白云石砂10～30％,镁钙砂5～20％,微粉1～6％,添加物1～5％,防爆纤维0.01～0.1％,补强纤维0.5～2％,复合结合剂0.5～4％,溶胶0.5～2％；其中添加物为硅线石、红柱石、蓝晶石、锆英石中的一种或几种；复合结合剂为Ca(OH)-(2)、Mg(OH)-(2)、磷酸盐、聚磷酸盐中的两种以上。本发明所述喷补料具有附着率高、回弹小等优点,使用后可延长浸渍管的使用寿命、减小喷补次数和喷补料消耗的特点；且涉及的制备方法较简单,适合推广应用。(The invention discloses a gunning mix with high RH adhesion rate, which is characterized by comprising the following components in percentage by mass: 30-60% of waste magnesia-chrome brick reclaimed materials, 20-45% of sintered magnesia, 10-30% of magnesium dolomite sand, 5-20% of magnesia-calcium sand, 1-6% of micro powder, 1-5% of additives, 0.01-0.1% of explosion-proof fibers, 0.5-2% of reinforcing fibers, 0.5-4% of composite binders and 0.5-2% of sol; wherein the additive is one or more of sillimanite, andalusite, kyanite and zircon; the composite binder is Ca (OH) 2 、Mg(OH) 2 Two or more of phosphate and polyphosphate. The gunning material has the advantages of high adhesion rate, small resilience and the like, and has the characteristics of prolonging the service life of the dip pipe and reducing gunning times and gunning material consumption after being used; and the related preparation method is simple and is suitable for popularization and application.)

1. The gunning mix with the high RH adhesion rate is characterized by comprising the following components in percentage by mass: 30-60% of waste magnesia-chrome brick reclaimed materials, 20-45% of sintered magnesia, 10-30% of magnesium dolomite sand, 5-20% of magnesia-calcium sand, 1-6% of micro powder, 1-5% of additives, 0.01-0.1% of explosion-proof fibers, 0.5-2% of reinforcing fibers, 0.5-4% of composite binders and 0.5-2% of sol; wherein the additive is one or more of sillimanite, andalusite, kyanite and zircon; the composite binder is Ca (OH)₂、Mg(OH)₂Two or more of phosphate and polyphosphate.

2. The RH high-adhesion gunning mix according to claim 1, wherein the recycled materials of waste magnesite-chrome bricks with different particle sizes and the mass percentages of the particles are as follows: 15-35% of 3-1mm particles, 20-35% of 1-0.5mm particles, 15-25% of 0.5-0.088mm particles and 10-30% of particles smaller than 0.088 mm; wherein MgO is more than 85 wt%, Cr₂O₃>5wt％。

3. The gunning mix with high RH attachment ratio according to claim 1, wherein the sintered magnesite grains with different particle sizes and their mass percentages comprise: 15-35% of 3-1mm particles, 20-35% of 1-0.5mm particles, 15-25% of 0.5-0.088mm particles and 10-30% of particles smaller than 0.088 mm; MgO is greater than 92 wt%.

4. The gunning mix with high RH attachment ratio according to claim 1, wherein the MgAIMoite sand comprises the following particles with different particle sizes and mass percentages thereof: 30-50% of particles with the diameter of 1-0.5mm, 15-35% of particles with the diameter of 0.5-0.088mm and 20-40% of particles with the diameter less than 0.088 mm; MgO is more than 60 wt%, CaO is more than 15 wt%.

5. The gunning mix with high RH attachment ratio according to claim 1, wherein the magnesite-calcia particles with different particle sizes and the mass percentages thereof comprise: 30-50% of particles with the diameter of 1-0.5mm, 15-35% of particles with the diameter of 0.5-0.088mm and 20-40% of particles with the diameter less than 0.088 mm; wherein CaO is more than 20 wt%, and MgO is more than 65 wt%.

6. The RH high adhesion gunning mix according to claim 1, wherein the micro powder is alumina, silica, ZrO₂One or more of MgO and SiC, and the average grain diameter is 0.05-0.2 μm.

7. The RH high-adhesion gunning mix according to claim 1, wherein the explosion-proof fiber has a diameter of 0.1-10 μm and a length of 1-5 mm; is one or more of polyethylene fiber, polypropylene fiber and polyester fiber.

8. The gunning mix with high RH adhesion ratio according to claim 1, wherein the sol is one or more of silica sol, aluminum sol or silica-alumina sol.

9. The method for preparing the RH high-adhesion-rate gunning mix as defined in any one of claims 1 to 8, comprising the steps of:

1) weighing the raw materials according to the proportion;

2) the preparation of the gunning material comprises the steps of firstly mixing the weighed aggregate, then adding the micro powder, the additive, the explosion-proof fiber, the reinforcing fiber, the composite binder and the sol, and continuously and uniformly mixing;

3) and forming and sintering the obtained mixture to obtain the RH high-adhesion-rate gunning mix.

Technical Field

The invention belongs to the technical field of refractory materials, and particularly relates to an RH high-adhesion gunning material and a preparation method thereof.

Background

The RH vacuum circulation degassing refining technology was successfully developed by Ruhrstahl and Heraeus in 1957, and is abbreviated as RH method. After the 80 s of the last century, the number of RH devices has increased rapidly, and the functions have been shifted from being mainly used for dehydrogenation to being mainly used for multifunctional external refining equipment such as deep decarburization and deoxidation, inclusion removal and the like. The RH refining furnace is subjected to long-term gas flow and high-speed washing of molten steel during use, and the operating conditions are very severe, whereas the operating conditions of the submerged pipe immersed in molten steel for a long period of time are the most severe among all the apparatuses constituting the RH furnace. The inner wall of the immersion pipe is not only washed by high-speed airflow and molten steel, but also the outer wall is eroded by slag and is rapidly cooled and heated. Meanwhile, the service life of the immersed tube is limited by various factors such as mechanical damage during cleaning of sticky slag on the outer wall of the immersed tube, mismatch of thermal expansion coefficients of the castable and the immersed tube core steel plate after being heated, and the immersed tube becomes the weakest link in RH refining equipment due to comprehensive factors. Therefore, how to improve the service life of the RH furnace dip pipe has been widely concerned and valued by the industry people.

In the field operation process, the service life of the RH furnace dip pipe is prolonged by adopting a mode of spraying and repairing refractory materials. Patent CN101367659A discloses a high-performance hot gunning mix for smelting silicon steel with a magnesium-calcium RH dip pipe, which mainly comprises high-purity magnesite and synthesized magnesium-calcium sand, organic additives such as calcium lignosulfonate and modified starch ether are compositely used to replace low-melting harmful plasticizers such as soft clay and water glass used in the conventional gunning mix so as to realize good gunning adhesion and good high-temperature performance of the gunning mix; CN102659432A discloses a novel RH gunning mix, which adopts fused magnesite coarse powder, fused magnesite fine powder and chrome sand as main raw materials, and is added with slaked lime, light calcium carbonate, sodium hexametaphosphate, borax, silicon micropowder, sodium tripolyphosphate and carboxymethyl cellulose in a matching way, so that the service life of an RH insertion tube can be obviously prolonged; CN108610062A discloses a magnesia-calcia refractory gunning mix, which takes magnesia, limestone and quicklime powder as main raw materials, and is added with titanium oxide powder, sodium dihydrogen phosphate, sodium hexametaphosphate, sodium carboxymethylcellulose and other bonding agents in an auxiliary manner, has higher high-temperature strength and rapid condensation performance, and can be applied to easily-washed parts of a converter, an electric furnace and an RH refining furnace. However, although the above-reported gunning materials have slightly improved performance, they are generally not high in the adhesion rate of the gunning materials, and the consumption of the gunning materials is large (the adhesion rate and the consumption are determined by the gunning rebound situation and the single-furnace gunning material consumption in the field implementation process), so that a lot of rebounding and waste are caused. Therefore, the research and development of the gunning mix for the dip pipe of the RH refining furnace with high adhesion rate have important significance for saving the consumption of refractory materials and prolonging the service life of the dip pipe.

Disclosure of Invention

The invention aims to provide the RH high-adhesion-rate gunning mix and the preparation method thereof, the gunning mix has the advantages of high adhesion rate, small resilience and the like, the service life of the dip pipe can be prolonged after the gunning mix is used, the gunning mix times and the gunning mix consumption are reduced, and the related preparation method is simple and is suitable for popularization and application.

In order to achieve the purpose, the invention adopts the technical scheme that:

the gunning mix with the high RH adhesion rate comprises the following components in percentage by mass: 30-60% of waste magnesia-chrome brick reclaimed materials, 20-45% of sintered magnesia, 10-30% of magnesium dolomite sand, 5-20% of magnesia-calcium sand, 1-6% of micro powder, 1-5% of additives, 0.01-0.1% of explosion-proof fibers, 0.5-2% of reinforcing fibers, 0.5-4% of composite binders and 0.5-2% of sol; wherein the additive is one or more of sillimanite, andalusite, kyanite and zircon; the composite binder is Ca (OH)₂、Mg(OH)₂More than two of phosphate (aluminum monohydrogen phosphate or aluminum dihydrogen phosphate) and polyphosphate (sodium tripolyphosphate or sodium hexametaphosphate).

In the scheme, the recycled materials of the waste magnesia-chrome bricks comprise the following particles with different particle sizes in percentage by mass: 15-35% of particles with the diameter of 3-1mm, 20-35% of particles with the diameter of 1-0.5mm, 15-25% of particles with the diameter of 0.5-0.088mm and 10-30% of particles with the diameter less than 0.088 mm.

In the scheme, the waste magnesia-chrome brick reclaimed material is classified and recycled by means of sorting, deironing, damage screening, chemical analysis and the like, wherein MgO is more than 85 wt%, and Cr is more than 85 wt%₂O₃>5wt％。

In the above scheme, the particles with different particle sizes in the sintered magnesite and the mass percentage of the particles with different particle sizes in the sintered magnesite comprise: 15-35% of 3-1mm particles, 20-35% of 1-0.5mm particles, 15-25% of 0.5-0.088mm particles and 10-30% of particles smaller than 0.088 mm; MgO is greater than 92 wt%.

In the above scheme, the magnesium dolomite sand comprises particles with different particle sizes and mass percentages thereof: 30-50% of particles with the diameter of 1-0.5mm, 15-35% of particles with the diameter of 0.5-0.088mm and 20-40% of particles with the diameter less than 0.088 mm; MgO is more than 60 wt%, CaO is more than 15 wt%.

In the above scheme, the magnesia-calcium sand comprises the following particles with different particle sizes and mass percentages thereof: 30-50% of particles with the diameter of 1-0.5mm, 15-35% of particles with the diameter of 0.5-0.088mm and 20-40% of particles with the diameter less than 0.088 mm; wherein CaO is more than 20 wt%, and Mg is more than 65 wt%.

In the scheme, the micro powder is alumina, silicon oxide and ZrO₂One or more of MgO and SiC, and the average grain diameter is 0.05-0.2 μm.

In the scheme, the average particle size of the additive is 0.5-0.088 mm.

In the scheme, the diameter of the explosion-proof fiber is 0.1-10 mu m, and the length of the explosion-proof fiber is 1-5 mm; one or more of polyethylene fiber, polypropylene fiber and polyester fiber can be selected.

In the scheme, the reinforcing fibers are metal fibers (selected from common steel fibers, heat-resistant steel fibers and the like) with the diameter of 0.1-1 mm and the length of 5-30 mm.

In the scheme, the sol is one or more of silica sol, aluminum sol or silicon-aluminum sol.

The preparation method of the RH high-adhesion-rate gunning mix comprises the following steps:

1) weighing the raw materials according to the proportion;

2) the gunning mix is prepared by weighing and selecting raw materials according to a preset proportion, mixing the raw materials by using a mixer, adding aggregate and mixing for 30 min-2 h in the mixing process, then gradually adding fine powder, additives, an explosion-proof agent, reinforcing fibers, a composite binding agent and sol and mixing for 1 h-10 h, bagging the uniformly mixed gunning mix and vacuumizing for later use.

In the scheme, the mixing time of the aggregate in the step 1) is 30 min-2 h.

In the scheme, the mixing time in the step 1) is 1-10 h.

Preferably, the mixture obtained in the step 1) is bagged and vacuumized for standby.

In the scheme, the performance of the final gunning material is detected by sample preparation and sintering according to the performance detection standard of the refractory material.

The RH high-adhesion-rate gunning material obtained according to the scheme has the volume density of 2.3-2.7 g/cm after being burnt at 1500 DEG C³The flexural strength after 1500 ℃ firing is 5-15 MPa, the linear change rate after 1500 ℃ firing is-3%, the flexural strength at 1200 ℃ high temperature is 0.8-2.5 MPa, 3-6 furnaces can be used for one-time spray repair, and the adhesion rate can reach 85-92%.

The principle of the invention is as follows:

according to the invention, the recycled waste magnesia-chrome brick material and the sintered magnesia are selected as main raw materials, so that a large amount of resources can be saved, the refractoriness of the gunning mix at high temperature can be fully ensured due to the existence of periclase crystal grains in the main crystal phases of the recycled waste magnesia-chrome brick material and the sintered magnesia, and meanwhile, magnesia-chrome spinel can be formed due to the existence of a small amount of chromium elements in the waste magnesia-chrome brick, so that the erosion resistance of the gunning mix is greatly improved;

on one hand, the introduction of the dolomite magnesite and the magnesia-calcium magnesite further improves the erosion resistance of the gunning material by introducing CaO, and simultaneously, the CaO, the MgO and the SiO₂The high-melting-point phase can be generated by reaction at high temperature, so that the bonding strength of the gunning material is further improved, the adhesion rate during gunning is improved, and the service life of the gunning material is greatly prolonged; meanwhile, the micro-expansion effect of additives such as andalusite and the like at high temperature can offset the sintering shrinkage of the gunning material at high temperature, so that the stripping phenomenon of a gunning layer caused by cracking is eliminated, and the adhesion rate of the gunning material is further improved;

the addition of the micro powder can improve the fluidity of the gunning material in the gunning process, and simultaneously, the micro powder reacts with the main material at high temperature to form an intercrystalline bonding phase with high melting point, so that the high-temperature strength of the gunning material is improved;

the explosion-proof fibers can be melted in the gunning mix to form an exhaust channel, so that moisture in the binding agent can be evaporated and discharged, and the gunning mix is prevented from bursting; the addition of the reinforcing fiber can improve the bonding strength of the using layer of the gunning material and prevent quick erosion in the using process;

the addition of the composite bonding agent and the sol can ensure the dispersion uniformity of the gunning material in the gunning process, and can also ensure that the sprayed gunning material can be quickly combined with a thermal-state dip pipe to prevent the gunning material from rebounding and falling off;

compared with the prior art, the invention has the beneficial effects that:

1) the gunning material for the dip pipe of the RH refining furnace has higher adhesion rate, and can effectively overcome the problems of short service life, low adhesion rate, large resilience and the like of the conventional gunning material.

2) The applicability is wide, and the method can be applied to the dip pipe of the RH refining furnace and can also be applied to the high-temperature resistant industry fields of steel ladles, tundishes, iron ladles and the like; after the spray repair is applied to the dip pipe, the service life of the dip pipe can be greatly prolonged, the spray repair times and the consumption of spray repair materials are reduced, and the spray repair is expected to be popularized and applied in large-scale production.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the content of the present invention, but the present invention is not limited to the following examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

The preparation method of the gunning mix with the high RH adhesion rate comprises the following steps:

1) weighing the raw materials according to the mixture ratio, wherein the raw materials and the mass percentage of the raw materials are as follows: 50 percent of waste magnesia-chrome brick reclaimed material (MgO is more than 95 percent) and sintered magnesia (MgO)>92%) 28%, magnesium dolomite sand 10%, magnesium calcium sand 5%, micropowder (alumina) 2%, additive 2% (andalusite), explosion-proof fiber 0.05%, reinforcing fiber 0.5%, composite binder 1.95% (Ca (OH)₂Phosphate in a mass ratio of 1:1), 0.5% of sol (silica sol); wherein the recycled material of the waste magnesia-chrome bricks contains particles with different particle sizes and the mass percentage of the particles is as follows: 35% of 3-1mm particles, 35% of 1-0.5mm particles, 15% of 0.5-0.088mm particles, less than15% of 0.088mm granules with an MgO content of 86 wt%, Cr₂O₃Is 5.5 wt%; the sintered magnesia comprises the following particles with different particle diameters in percentage by mass: 25% of 3-1mm particles, 30% of 1-0.5mm particles, 25% of 0.5-0.088mm particles and 20% of particles smaller than 0.088 mm; 30 percent of magnesium dolomite sand particles with the particle size of 1-0.5mm, 30 percent of particles with the particle size of 0.5-0.088mm and 40 percent of particles with the particle size less than 0.088mm, wherein the content of MgO is 62 percent by weight; the magnesia-calcium sand comprises the following particles with different grain diameters in percentage by mass: 40% of particles with the diameter of 1-0.5mm, 30% of particles with the diameter of 0.5-0.088mm and 30% of particles with the diameter less than 0.088mm, wherein the content of CaO is 22%, and the content of MgO is 67 wt%; the average grain diameter of the alumina micro powder is 0.05 micron; the average grain diameter of the andalusite is 0.1 mm; the explosion-proof fiber is organic fiber (polypropylene fiber) with the diameter of 1 mu m and the length of 3 mm; the reinforcing fiber is metal fiber (heat-resistant steel fiber) with the diameter of 0.5mm and the length of 15 mm; SiO in silica sol₂The content is 25 wt%;

2) and mixing the weighed raw materials by using a mixer, adding aggregate and mixing for 30min in the mixing process, then gradually adding the fine powder, the additive, the explosion-proof fiber, the reinforcing fiber, the composite binder and the sol, mixing for 5h, uniformly mixing, bagging the obtained mixture and vacuumizing for later use to obtain the RH high-adhesion-rate gunning mix.

The product obtained in this example was tested to have a bulk density of 2.57g/cm after firing at 1500 deg.C³The flexural strength after 1500 ℃ firing is 6.5MPa, the linear change rate after 1500 ℃ firing is-1.3%, the flexural strength at 1200 ℃ high temperature is 1.2MPa, 3 furnaces can be used for one-time spray repair, and the adhesion rate is 87%.

Example 2

The preparation method of the gunning mix with the high RH adhesion rate comprises the following steps:

1) weighing the raw materials according to the mixture ratio, wherein the raw materials and the mass percentage of the raw materials are as follows: 55 percent of waste magnesia-chrome brick reclaimed material (MgO is more than 95 percent) and sintered magnesia (MgO)>92 percent), 20 percent of magnesium dolomite sand, 13 percent of magnesium calcium sand, 5 percent of micro powder (alumina and silica micro powder), 3 percent of additive (andalusite), 0.03 percent of explosion-proof fiber, 0.8 percent of reinforcing fiber and 1.17 percent of composite binder (Mg (OH)₂The mass ratio of the aluminum sol to the phosphate is 1:2), 1 percent of sol (aluminum sol, Al)₂O₃The content is more than 20wt percent); wherein the recycled material of the waste magnesia-chrome bricks contains particles with different particle sizes and the mass percentage of the particles is as follows: 30% of 3-1mm particles, 35% of 1-0.5mm particles, 20% of 0.5-0.088mm particles and 15% of particles smaller than 0.088mm, wherein the MgO content is 88.5 wt%, and the Cr content is₂O₃The content of (B) is 6.5 wt%; the sintered magnesia comprises the following particles with different particle diameters in percentage by mass: 25% of 3-1mm particles, 30% of 1-0.5mm particles, 25% of 0.5-0.088mm particles and 20% of particles smaller than 0.088 mm; 30 percent of magnesium dolomite sand particles with the particle size of 1-0.5mm, 30 percent of particles with the particle size of 0.5-0.088mm and 40 percent of particles with the particle size less than 0.088mm, wherein the content of MgO is 63 percent by weight; the magnesia-calcium sand comprises the following particles with different grain diameters in percentage by mass: 40% of particles with the diameter of 1-0.5mm, 30% of particles with the diameter of 0.5-0.088mm and 30% of particles with the diameter less than 0.088mm, wherein the content of CaO is 25%, and the content of MgO is 66.5 wt%; the micro powder is prepared by adding aluminum oxide and silicon oxide micro powder according to the mass ratio of 1:1, and the average grain diameter is 0.1 micron; the particle size of the andalusite is 0.1 mm; the explosion-proof agent is organic fiber (polyethylene fiber) with the diameter of 2 mu m and the length of 3.5 mm; the reinforcing fiber is metal fiber (heat-resistant steel fiber) with the diameter of 0.6mm and the length of 20 mm; SiO in silica sol₂The content is 25%;

2) and mixing the weighed raw materials by using a mixer, adding aggregate and mixing for 1min in the mixing process, then gradually adding fine powder, additives, an explosion-proof agent, a reinforcing fiber, a composite binding agent and sol, mixing for 4h, uniformly mixing, bagging the obtained mixture and vacuumizing for later use to obtain the RH high-adhesion-rate gunning mix.

The product obtained in this example was tested to have a bulk density of 2.45g/cm after firing at 1500 deg.C³The flexural strength after 1500 ℃ firing is 8.5MPa, the linear change rate after 1500 ℃ firing is-1.6%, the flexural strength at 1200 ℃ high temperature is 1.5MPa, 4 furnaces can be used for one time of spray repair, and the adhesion rate is 88%.

Example 3

The preparation method of the gunning mix with the high RH adhesion rate comprises the following steps:

1) weighing the raw materials according to the mixture ratio, wherein the raw materials and the mass percentage of the raw materials are as follows: 43 percent of waste magnesia-chrome brick reclaimed material (MgO is more than 95 percent) and sintered magnesia (MgO)>92%) 30%, magnesium dolomite sand 13%, magnesium7% of calcium sand, 2% of micro powder (alumina and MgO micro powder), 1% of additive (zircon), 0.05% of explosion-proof fiber, 0.95% of reinforcing fiber and 2% of composite binder (Mg (OH)₂The mass ratio of the phosphate is 1:3), and 1% of sol (aluminum sol); wherein the recycled material of the waste magnesia-chrome bricks contains particles with different particle sizes and the mass percentage of the particles is as follows: 35% of 3-1mm particles, 30% of 1-0.5mm particles, 20% of 0.5-0.088mm particles and 15% of particles smaller than 0.088mm, wherein the MgO content is 88 wt%, and the Cr content is₂O₃The content of (B) is 7.2 wt%; the sintered magnesia comprises the following particles with different particle diameters in percentage by mass: 35% of 3-1mm particles, 30% of 1-0.5mm particles, 25% of 0.5-0.088mm particles and 10% of particles smaller than 0.088 mm; 40% of magnesium dolomite sand particles with the particle size of 1-0.5mm, 30% of magnesium dolomite sand particles with the particle size of 0.5-0.088mm and 30% of magnesium dolomite sand particles with the particle size of less than 0.088mm, wherein the content of MgO is 64 wt%; the magnesia-calcium sand comprises the following particles with different grain diameters in percentage by mass: 35% of particles with the diameter of 1-0.5mm, 25% of particles with the diameter of 0.5-0.088mm and 40% of particles with the diameter less than 0.088mm, wherein the content of CaO is 21 wt% and the content of MgO is 68 wt%; the micro powder is prepared by mixing alumina and MgO micro powder according to the mass ratio of 1:1, and the average grain diameter is 0.1 micron; the particle size of the andalusite is 0.1 mm; the explosion-proof agent is organic fiber (polyester fiber) with the diameter of 5 mu m and the length of 5 mm; the reinforcing fiber is metal fiber (heat-resistant steel fiber) with the diameter of 0.2mm and the length of 15 mm; silica-alumina sol of which SiO₂15 wt% of Al₂O₃10 wt% of the total weight of the composition;

2) and mixing the weighed raw materials by using a mixer, adding aggregate and mixing for 1min in the mixing process, then gradually adding fine powder, additives, an explosion-proof agent, a reinforcing fiber, a composite binding agent and sol, mixing for 4h, uniformly mixing, bagging the obtained mixture and vacuumizing for later use to obtain the RH high-adhesion-rate gunning mix.

The product obtained in this example was tested to have a bulk density of 2.53g/cm after firing at 1500 deg.C³The flexural strength after 1500 ℃ firing is 7.1MPa, the linear change rate after 1500 ℃ firing is 1.1 percent, the flexural strength at 1200 ℃ high temperature is 1.8MPa, 5 furnaces can be used for one-time spray repair, and the adhesion rate is 90 percent.

Example 4

The preparation method of the gunning mix with the high RH adhesion rate comprises the following steps:

1) weighing the raw materials according to the mixture ratio, wherein the raw materials and the mass percentage of the raw materials are as follows: 40% of waste magnesia-chrome brick reclaimed material (MgO is more than 95%), and sintered magnesia (MgO)>92 percent), 26 percent of magnesium dolomite sand, 15 percent of magnesium calcium sand, 10 percent of micro powder (silicon oxide, ZrO)₂2% of SiC, 3% of additive (zircon and sillimanite added according to the mass ratio of 1:1), 0.03% of explosion-proof fiber, 0.5% of reinforcing fiber and 1.97% of composite binder (Ca (OH)₂The mass ratio of the phosphate to the polyphosphate is 1:1:1), and 1.5% of sol (aluminum sol); wherein the recycled material of the waste magnesia-chrome bricks contains particles with different particle sizes and the mass percentage of the particles is as follows: 35% of 3-1mm particles, 35% of 1-0.5mm particles, 15% of 0.5-0.088mm particles and 15% of particles smaller than 0.088mm, wherein the MgO content is 89 wt%, and the Cr content is₂O₃Is 5.5 wt%; the sintered magnesia comprises the following particles with different particle diameters in percentage by mass: 25% of 3-1mm particles, 30% of 1-0.5mm particles, 25% of 0.5-0.088mm particles and 10% of particles smaller than 0.088 mm; 30 percent of magnesium dolomite sand particles with the particle size of 1-0.5mm, 30 percent of particles with the particle size of 0.5-0.088mm and 40 percent of particles with the particle size less than 0.088mm, wherein the content of MgO is 63 percent by weight; the magnesia-calcium sand comprises the following particles with different grain diameters in percentage by mass: 40% of particles with the diameter of 1-0.5mm, 30% of particles with the diameter of 0.5-0.088mm and 30% of particles with the diameter less than 0.088mm, wherein the content of CaO is 26% and the content of MgO is 66 wt%; the micro powder is made of silicon oxide and ZrO₂Adding SiC micro powder according to the mass ratio of 2:1:1, wherein the average particle size is 0.1 micron; the average grain diameter of the andalusite and the sillimanite is 0.3 mm; the explosion-proof agent is organic fiber with the diameter of 3 mu m and the length of 3.5mm (the polypropylene fiber and the polyethylene fiber are added according to the mass ratio of 1: 1); the reinforcing fiber is metal fiber (common steel fiber) with the diameter of 0.7mm and the length of 20 mm; SiO 2₂30% silica sol and Al₂O₃35 percent of aluminum sol, the mass ratio is 1: 1;

2) and mixing the weighed raw materials by using a mixer, adding aggregate and mixing for 1.5 hours in the mixing process, then gradually adding fine powder, additives, an explosion-proof agent, a reinforcing fiber, a composite bonding agent and sol and mixing for 6 hours, uniformly mixing, bagging the obtained mixture and vacuumizing for later use to obtain the RH high-adhesion-rate gunning mix.

After testing, the bookExample the product obtained has a bulk density after firing at 1500 ℃ of 2.6g/cm³The flexural strength after 1500 ℃ firing is 9.0MPa, the linear change rate after 1500 ℃ firing is-1.5%, the flexural strength at 1200 ℃ high temperature is 2.0MPa, 5 furnaces can be used for one time of spray repair, and the adhesion rate is 90%.

It is apparent that the above embodiments are only examples for clearly illustrating and do not limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications are therefore intended to be included within the scope of the invention as claimed.