Active auxiliary cementing material prepared by red mud tempering and method
阅读说明：本技术 一种赤泥调质制备的活性辅助胶凝材料及方法 (Active auxiliary cementing material prepared by red mud tempering and method ) 是由 胡月阳 王路明 于 2021-10-20 设计创作，主要内容包括：本发明公开了一种赤泥调质制备的活性辅助胶凝材料及方法,将烘干赤泥和调质原料均匀的混合,得到混合物A；将混合物A加热到1000-1500℃,得到液相的混合物B,维持该温度0.3-3h得到充分反应的液相混合物C；将混合物C直接采用急速冷却的方式进行冷却,冷却后得到的调质赤泥D；将得到的调质赤泥D进行烘干处理,并进行粉磨即得。本发明对赤泥进行调质制备活性辅助胶凝材料,一方面利用赤泥中的铁铝等材料,将其活化为玻璃体；另一方面利用赤泥中的碱达到液相低温形成的目的,该种方法能够大幅的提升赤泥活性,并且降低处理的温度。(The invention discloses an active auxiliary cementing material prepared by red mud tempering and a method thereof, wherein the dried red mud and the tempering raw material are uniformly mixed to obtain a mixture A; heating the mixture A to 1000-1500 ℃ to obtain a liquid phase mixture B, and maintaining the temperature for 0.3-3h to obtain a fully reacted liquid phase mixture C; directly cooling the mixture C in a rapid cooling mode to obtain tempered red mud D after cooling; and drying the obtained tempered red mud D, and grinding to obtain the finished product. According to the invention, the red mud is quenched and tempered to prepare the active auxiliary cementing material, on one hand, materials such as iron, aluminum and the like in the red mud are utilized to be activated into a vitreous body; on the other hand, the purpose of forming a liquid phase at low temperature is achieved by using alkali in the red mud, the method can greatly improve the activity of the red mud and reduce the treatment temperature.)
1. The method for preparing the active auxiliary cementing material by red mud tempering is characterized by comprising the following steps:
(1) weighing quenched and tempered raw materials of the dried red mud and the red mud;
(2) uniformly mixing the dried red mud obtained in the step (1) with a tempering raw material to obtain a mixture A;
(3) heating the mixture A to 1000-1500 ℃ to obtain a liquid phase mixture B, and maintaining the temperature for 0.3-3h to obtain a fully reacted liquid phase mixture C;
(4) directly cooling the mixture C in a rapid cooling mode to obtain tempered red mud D after cooling;
(5) and drying the obtained tempered red mud D, and grinding to obtain the finished product.
2. The method for preparing the active auxiliary cementing material by red mud refining according to claim 1, wherein in the step (1), the refining raw material of the red mud is any one or a mixture of more than two of fly ash, slag, silica fume, clay, iron tailings, lime, calcium hydroxide, calcium carbide, steel slag or limestone.
3. The method for preparing the active auxiliary cementing material by red mud refining according to claim 1, wherein in the step (1), the proportion of the red mud refining raw material to the dried red mud is calculated according to the following mass percent:
red mud: 40% -80%;
tempering raw materials: 20 to 60 percent.
4. The method for preparing the active auxiliary cementing material by red mud refining as claimed in claim 1, wherein in the step (1), the specific surface area of the dried red mud is 150-500m2/kg。
5. The method for preparing the active auxiliary cementing material by red mud refining as claimed in claim 1, wherein in the step (1), the specific surface area of the refining raw material is 200-400m2/kg。
6. The method for preparing the active auxiliary cementing material by red mud refining as claimed in claim 1, wherein in the step (3), the mixture A is heated to 1000-1500 ℃ at a heating rate of 5-50 ℃/min.
7. The method for preparing the active auxiliary cementing material by red mud refining as claimed in claim 1, wherein in the step (4), the rapid cooling mode comprises water cooling, liquid nitrogen cooling or argon cooling.
8. The red mud refining active auxiliary cementing material prepared by any one of the preparation methods in the claims 1 to 7.
9. The red mud refining active auxiliary cementing material as claimed in claim 8, characterized in that the specific surface area thereof is 300-800m2/kg。
10. The red mud refining active auxiliary cementitious material according to claim 8, characterized in that the activity index of the material is not less than 60% in 7 days and not less than 80% in 28 days.
Technical Field
The invention belongs to the field of solid waste recycling treatment, and particularly relates to an active auxiliary cementing material prepared by red mud conditioning and a method.
Background
Along with the rapid development of economy, urbanization is continuously promoted, people have greater and greater demand for aluminum products in order to better build cities, and a large amount of industrial byproduct red mud is generated. With the rising of building material cost and the rising of environmental protection requirements of people in recent years, the resource utilization of red mud which is an industrial waste becomes a trend.
The red mud is a byproduct generated in the production process of extracting aluminum, and because the red mud contains more alkali and less active materials, when the red mud is used as an additive of a building material, minerals in cement can be affected to form alkali silicate reaction, so that the performance of cement concrete and building material products is greatly reduced, and finally safety accidents are caused.
The utilization of the red mud at the present stage mainly adopts a technology of removing alkali at high temperature and preparing cement, the reaction temperature of raw materials is raised, so that the alkali forms steam before clinker is calcined, the alkali is discharged from gas through a bypass air discharging technology, and the residual red mud is used as a cement correction raw material, so that the purpose of resource utilization of the red mud in the cement is achieved, but in the running process of the method, the red mud is firstly dried and ground, a large amount of energy is consumed, and in the grinding process, the red mud is easy to attach to a grinding machine, so that the energy consumption is further increased; secondly, in the process of removing alkali from the ground red mud, when the bypass is ventilated, the heat is greatly weakened, so that the energy consumption is continuously increased. This method is therefore costly.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the defects of the prior art, the invention provides an active auxiliary cementing material prepared by red mud conditioning and a method thereof, so as to eliminate the influence of alkali in the red mud on the material, improve the activity of inactive materials in the red mud and enable the red mud after conditioning to be used as the auxiliary cementing material.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a method for preparing an active auxiliary cementing material by red mud tempering comprises the following steps:
(1) weighing quenched and tempered raw materials of the dried red mud and the red mud;
(2) uniformly mixing the dried red mud obtained in the step (1) with a tempering raw material to obtain a mixture A;
(3) heating the mixture A to 1000-1500 ℃, preferably 1400-1500 ℃ to obtain a liquid phase mixture B, and maintaining the temperature for 0.3-3h, preferably 0.5-1 h to obtain a fully reacted liquid phase mixture C;
(4) directly cooling the mixture C in a rapid cooling mode to obtain tempered red mud D after cooling;
(5) and drying the obtained tempered red mud D, and grinding to obtain the finished product.
Specifically, in the step (1), the red mud refining raw material is any one or a mixture of two or more of fly ash, slag, silica fume, metakaolin, clay, iron tailings, lime, calcium hydroxide, calcium carbide, steel slag and limestone, preferably any one or a mixture of two or more of fly ash, steel slag and metakaolin.
Preferably, in the step (1), the proportion of the red mud refining raw material to the dried red mud is calculated according to the following mass percentage:
red mud: 40% -80%, preferably 50-65%;
tempering raw materials: 20 to 60 percent.
Preferably, in the step (1), the specific surface area of the dried red mud is 150-500m2/kg。
Preferably, in the step (1), the specific surface area of the modified raw material is 200-400m2/kg。
Preferably, in step (3), the mixture A is heated to 1000-1500 ℃ at a heating rate of 5-50 ℃/min.
Specifically, in the step (4), the rapid cooling mode includes water cooling, liquid nitrogen cooling or argon cooling.
Further, the red mud refining active auxiliary cementing material prepared by the preparation method is also within the protection scope of the invention.
Specifically, the specific surface area of the red mud conditioning active auxiliary cementing material prepared by the invention is 300-800m2/kg。
Specifically, according to the detection of national standard GB/T18046-2017, the activity index of the red mud quenching and tempering active auxiliary cementing material prepared by the invention in 7 days is not lower than 60%, and the activity index in 28 days is not lower than 80%.
Has the advantages that:
(1) according to the invention, the red mud is quenched and tempered to prepare the active auxiliary cementing material, on one hand, materials such as iron, aluminum and the like in the red mud are utilized to be activated into a vitreous body; on the other hand, the purpose of forming a liquid phase at low temperature is achieved by using alkali in the red mud, the method can greatly improve the activity of the red mud and reduce the treatment temperature. The active auxiliary cementing material prepared by the invention utilizes alkali in the red mud to form a liquid phase at a lower temperature, thereby reducing the formation temperature of the liquid phase and reducing the energy consumption. In addition, alkali in the red mud is solidified in a vitreous body, and the time of outward precipitation is far longer than the influence of the soda ash on a cement-based material, so that the active auxiliary cementing material prepared by the method has good safety when being applied.
(2) The cooling mode adopted by the invention is a rapid cooling mode, and the red mud quenched and tempered under the condition forms a solid-phase glass body from a liquid phase rapidly, so that alkali and other harmful materials can be coated in the glass body, and secondary pollution can not be caused.
(3) According to the invention, the ferro-aluminum and the silicon material in the red mud are prepared into the vitreous body, so that the limitation that only silicon is activated at the present stage is broken through, all the materials in the red mud can be utilized, the actual utilization value is created, and the high-value utilization of the red mud is realized.
Drawings
The foregoing and/or other advantages of the invention will become further apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.
FIG. 1 is an XRD pattern of an active supplementary cementitious material prepared in example 1.
FIG. 2 is a photograph of red mud in example 1 before and after refining.
FIG. 3 is a graph comparing the performance of the conditioned red mud as an auxiliary cementitious material in cement in example 1.
Detailed Description
The invention will be better understood from the following examples.
In the following examples, undisturbed red mud, fly ash, metakaolin, calcium hydroxide, steel slag, limestone were obtained from commercially randomly purchased samples. Wherein the specific surface area of the red mud is 283m2Per kg, specific surface area of the fly ash 335m2Per kg, metakaolin specific surface area 264m2/kg。
Example 1
In the embodiment, the red mud quenching and tempering active auxiliary cementing material is prepared by weighing the following raw materials in percentage by mass:
the preparation method comprises the following steps:
(1) weighing the dried red mud, the fly ash, the metakaolin and the calcium hydroxide according to the proportion, and fully mixing to obtain a mixture A;
(2) heating the mixture A to 1500 ℃ at the speed of 10 ℃/min to obtain a liquid-phase mixture B, and then keeping the temperature for 1h to obtain a fully-reacted liquid-phase mixture C;
(3) directly pouring the liquid-phase mixture C into circulating water for cooling to obtain the quenched and tempered red mud D, drying and grinding to obtain the auxiliary cementing material, namely the required finished product, wherein the specific surface area is 350m2In terms of/kg. The finished product is added into cement to determine the activity index, and the activity index in 7 days is 60 percent and the activity index in 28 days is 81 percent according to the standard detection of national standard GB/T18046-2017.
The product obtained in example 1 was subjected to XRD characterization as shown in FIG. 1. As can be seen from the figure, through the quenching and tempering mode of the invention, the obtained red mud quenching and tempering activity auxiliary cementing material has an amorphous phase peak in the range of 20-40 degrees, and particularly, the amorphous phase peak appearing around 30 degrees represents that the red mud quenching and tempering activity auxiliary cementing material has higher activity. In addition, it can be also obviously seen from the appearance that the red mud after tempering presents the appearance of a glossy vitreous phase, as shown in fig. 2, wherein the left side is a photograph of the red mud before tempering, and the right side is the red mud tempering active auxiliary cementing material with the vitreous appearance.
Example 2
In the embodiment, the red mud quenching and tempering active auxiliary cementing material is prepared by weighing the following raw materials in percentage by mass:
the preparation method comprises the following steps:
(1) weighing the dried red mud, the steel slag, the metakaolin and the limestone according to the proportion, and fully mixing to obtain a mixture A;
(2) heating the mixture A to 1450 ℃ at the speed of 20 ℃/min to obtain a liquid-phase mixture B, and then keeping the temperature for 0.8h to obtain a fully-reacted liquid-phase mixture C;
(3) directly pouring the liquid-phase mixture C into liquid nitrogen for cooling to obtain the quenched and tempered red mud D, drying and grinding to obtain the auxiliary cementing material, namely the required finished product, wherein the specific surface area is 360m2In terms of/kg. The finished product is added into cement to determine the activity index, and the activity index in 7 days is 62 percent and the activity index in 28 days is 83 percent according to the standard detection of national standard GB/T18046-2017.
Example 3
In the embodiment, the red mud quenching and tempering active auxiliary cementing material is prepared by weighing the following raw materials in percentage by mass:
drying the red mud by 65 percent,
30 percent of steel slag,
5 percent of metakaolin.
The preparation method comprises the following steps:
(1) weighing the dried red mud, the steel slag and the metakaolin according to the proportion, and fully mixing to obtain a mixture A;
(2) heating the mixture A to 1400 ℃ at the speed of 15 ℃/min to obtain a liquid-phase mixture B, and then keeping the temperature for 0.5h to obtain a fully-reacted liquid-phase mixture C;
(3) directly pouring the liquid-phase mixture C into liquid nitrogen for coolingDrying and grinding the obtained modified red mud D to obtain an auxiliary cementing material, namely a required finished product with the specific surface area of 400m2In terms of/kg. The finished product is added into cement to determine the activity index, and the activity index in 7 days is 64 percent and the activity index in 28 days is 85 percent according to the standard detection of national standard GB/T18046-2017.
The red mud thermally refining activated supplementary cementitious material prepared in example 1 was incorporated in 50 wt% into cement in comparison with granulated blast furnace slag powder test standard GB/T17671-1999 for cement, mortar and concrete, and ordinary portland cement of reference P.II 52.5 according to cement mortar strength test standard GB/T17671-1999, and the 7-day and 28-day strengths of which are shown in FIG. 3. As can be seen from fig. 3: compared with cement doped with slag, the cement doped with 50 wt% of the quenched and tempered red mud has the advantages that the compressive strength is enhanced in 7 days and 28 days, and the quenched and tempered red mud can be excited under an alkaline condition, has the characteristic of an auxiliary cementing material, and can replace the slag to become a novel auxiliary cementing material.
The invention breaks through the limitation of utilization of alkali and inactive aluminum iron in the red mud, designs and optimizes the proportion of the mineral composition to regulate and control the red mud into an active vitreous material, eliminates the harm of the alkali in the red mud in the building materials through regulation and control, and also prepares the red mud into an auxiliary cementing material with high added value.
The invention provides a thought and a method for preparing an active auxiliary cementing material by red mud tempering, and a method for realizing the technical scheme, and the above description is only a preferred embodiment of the invention, and it should be noted that, for a person skilled in the art, several improvements and decorations can be made without departing from the principle of the invention, and the improvements and decorations should be regarded as the protection scope of the invention. All the components not specified in the present embodiment can be realized by the prior art.