CN115466073B - Steel slag material doped with ammonium salt-graphene composite activator and preparation method thereof - Google Patents

Abstract

The invention discloses a steel slag material doped with an ammonium salt-graphene composite activator and a preparation method thereof, belonging to the technical field of industrial additives. Described ammonium salt-graphene composite activator comprises ammonium salt and graphene, and wherein, ammonium salt is the compound of ammonium chloride, ammonium bicarbonate and ammonium sulfate, and graphene is multilayer graphene, and the combination of ammonium salt and graphene The mass ratio is (10-15):1. The ammonium salt-graphene composite activator-doped steel slag material and preparation method of the present invention have simple and easy-to-obtain raw materials and low cost, and the steel slag after doping modification has good compression resistance, flexural resistance and stability effects, and can be used It is applied to concrete; the preparation method is simple, convenient and harmless, and does not produce any waste gas or waste liquid, and is suitable for large-scale industrial production.

Description

Steel slag material doped with ammonium salt-graphene composite activator and preparation method thereof

technical field

The invention belongs to the technical field of industrial additives, and in particular relates to a steel slag material doped with an ammonium salt-graphene composite activator and a preparation method thereof.

Background technique

Steel slag is an inevitable solid waste in the steelmaking process. According to the data of the National Bureau of Statistics of China, China's crude steel output will reach 1.065 billion tons in 2020, ranking first in the world. According to the proportion of steel slag production in China, it accounts for 15% of crude steel output. It can be estimated that China's steel slag production in 2020 will be about 160 million tons, and the cumulative storage exceeds 1 billion tons. In China, steel slag is generally recycled within enterprises for low-value-added uses such as roadbed materials, steel slag bricks, and wastewater treatment. Not only is the utilization rate low, but it will also cause secondary pollution. At present, the comprehensive utilization rate of steel slag in China is low, only about 30%, which is far behind developed countries, especially in road construction and internal recycling in iron and steel enterprises.

Steel slag tailings with good stability have enough market space, such as concrete fine aggregate, concrete porous bricks and pavement bricks, ordinary ready-mixed mortar, steel slag micropowder, etc., steel slag tailings can be used as the main raw material, only fine aggregate The industry has a market capacity of billions of tons. The large-scale resource utilization of steel slag can not only reduce the cost of waste slag treatment and reduce environmental pressure, but also has huge economic benefits, and the market prospect is very promising. However, there are many problems in the utilization of steel slag.

In the ordinary cement concrete system, the total amount of phases contained in steel slag that can be hydrated within 28 days and directly contribute to the strength of concrete is negligibly small. These active substances are well-developed and have large grain sizes, making it difficult to exert gelling properties. Secondly, the composition of steel slag is complex, and its main components include CaO, SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , MgO, FeO and P ₂ O ₅ , and the specific chemical composition fluctuates greatly with different steelmaking raw materials and processes. It brings certain difficulties to production control; in addition, steel slag is unstable. When exposed to the air, the free f-CaO and f-MgO inside the steel slag product will gradually absorb the moisture in the air to form Ca(OH) ₂ and Mg(OH) _2. The volume expansion of more than 1 times will be generated, which will cause the steel slag products to crack and fall off, leaving potential safety hazards. To sum up, it is difficult to process steel slag and its application, which limits the recycling of steel slag and brings concerns to users in the application of steel slag products. Therefore, the large-scale application of steel slag also depends on the development of steel slag processing technology.

Contents of the invention

The object of the present invention is to propose a steel slag material doped with an ammonium salt-graphene composite activator and a preparation method for the problems in the background technology. The ammonium salt-graphene composite activator of the present invention can effectively improve the activity of steel slag and solve the environmental pollution problem caused by the accumulation of a large amount of steel slag; at the same time, it can also reasonably use steel slag instead of cement clinker and apply it to the construction industry to reduce _CO2 in cement enterprises emissions and reduce construction costs.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

A kind of ammonium salt-graphene compound activator, comprises ammonium salt and graphene, and wherein, ammonium salt is the compound of ammonium chloride, ammonium bicarbonate and ammonium sulfate, and graphene is multilayer graphene, and ammonium salt and graphene The mass ratio is (10-15):1.

Further, in the ammonium salt, the mass fraction of ammonium chloride is 20wt%-35wt%, the mass fraction of ammonium bicarbonate is 35wt%-65wt%, and the mass fraction of ammonium sulfate is 15wt%-30wt%.

A steel slag material doped with an ammonium salt-graphene composite activator, comprising the above-mentioned ammonium salt-graphene composite activator and steel slag, and the mass ratio of the ammonium salt-graphene composite activator to steel slag is 1:(10 ~30).

A kind of preparation method of the steel slag material doped with ammonium salt-graphene composite activator, comprises the following steps:

Step 1, weighing raw materials:

According to the ratio of "20wt%-35wt% ammonium chloride, 35wt%-65wt% ammonium bicarbonate, 15wt%-30wt% ammonium sulfate", three ammonium salts of ammonium chloride, ammonium bicarbonate and ammonium sulfate were weighed as raw materials;

Step 2, ball milling:

Put the raw materials weighed in step 1 into a ball mill for ball milling, the ball milling speed is 30-40r/min, the ball milling time is 5min, after the ball milling is completed, the ammonium salt compound is obtained;

Step 3, mix with graphene:

Mix the ammonium salt compound obtained in step 2 with graphene according to the mass ratio of (10-15): 1, ball mill, the ball milling speed is 200r/min, the ball milling time is 10min, after the ball milling is completed, ammonium salt-graphite is obtained ene complex activator;

Step 4, mixing with steel slag:

Add the ammonium salt-graphene composite activator obtained in step 3 to the steel slag, the mass ratio of the ammonium salt-graphene composite activator to the steel slag is 1: (10-30); then, put it into a ball mill for ball milling, The ball milling speed is 30~40r/min, and the ball milling time is 10min;

Step 5, drying:

After the ball milling is completed, put it into a constant temperature drying oven, react and dry at a temperature of 40-50° C. for 20 minutes, and obtain the steel slag material doped with the ammonium salt-graphene composite activator.

The present invention provides a steel slag material doped with an ammonium salt-graphene composite activator and a preparation method thereof. The steel slag material is doped with a compound of three ammonium salts and graphene as an activator, and any of the three ammonium salts can be used. Provide NH ₄ ⁺ , NH ₄ ⁺ can promote the depolymerization of glass body and RO phase in steel slag (dissociation of a large number of Ca–O and Al–O bonds), and promote the re-reaction of Ca ²⁺ and Al ²⁺ after dissociation Gelling substances C–(A)–S–H. At the same time, the ammonium salt complex can be decomposed to produce CO ₂ microcapsules, which can react with free f–CaO to generate CaCO ₃ , which solves the stability problem of steel slag and improves the safe use performance of steel slag. In addition, ammonium bicarbonate in the ammonium salt is alkaline, while ammonium chloride and ammonium sulfate are weakly acidic. Such an acid-base environment is more likely to dissociate the aggregates in the steel slag and continue to undergo hydration reactions, which is conducive to improving The steel slag active substance C–S–H; the addition of graphene can promote the excitation reaction, accelerate the hydration reaction, and further generate more gelling substances C–S–H.

Compared with prior art, the beneficial effect of the present invention is:

1. The ammonium salt-graphene composite activator-doped steel slag material and preparation method provided by the present invention have simple and easy-to-obtain raw materials and low cost, and the compression resistance, flexural resistance and stability effects of the modified steel slag after doping Very good for use in concrete.

2. The ammonium salt-graphene composite activator-doped steel slag material and preparation method provided by the present invention are simple, convenient and harmless, and will not produce any waste gas or liquid, and are suitable for large-scale industrial production.

3. The steel slag material doped with the ammonium salt-graphene composite activator in Example 4 of the present invention is mixed with P.O 42.5 cement at a ratio of 3:7 according to the GB/T17671-1999 test standard, and placed in a water culture environment at 20°C Among them, after 28 days of curing, its compressive strength can reach 39.3Mpa; according to the Rayleigh clip method in the GB/T1346-2011 test standard, its stability has been reduced from 2mm to 0.5mm.

Detailed ways

Below in conjunction with embodiment the present invention will be further described. Apparently, the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

A kind of preparation method of the steel slag material doped with ammonium salt-graphene composite activator, specifically comprises the following steps:

Step 1, weighing raw materials:

According to the ratio of "20wt% ammonium chloride, 65wt% ammonium bicarbonate, 15wt% ammonium sulfate", three ammonium salts of ammonium chloride, ammonium bicarbonate and ammonium sulfate were weighed as raw materials;

Step 2, ball milling:

Put the raw materials weighed in step 1 into a ball mill for ball milling, the ball milling speed is 38r/min, the ball milling time is 5min, after the ball milling is completed, the ammonium salt compound is obtained;

Step 3, mix with graphene:

The ammonium salt compound obtained in step 2 is mixed with graphene according to the mass ratio of 12:1, ball milled, the ball milling speed is 200r/min, and the ball milling time is 10min. After the ball milling is completed, the ammonium salt-graphene composite activator is obtained ;

Step 4, mixing with steel slag:

Add the ammonium salt-graphene composite activator obtained in step 3 to the steel slag, the mass ratio of the ammonium salt-graphene composite activator to the steel slag is 1:20; then, put it into a ball mill for ball milling, the ball milling speed is 35r /min, the ball milling time is 10min; wherein, the steel slag components are: CaO 45wt%-56wt%, SiO ₂ 10wt%-15wt%, Al ₂ O ₃ 1.8wt%-4wt%, Fe ₂ O ₃ 20wt%-28wt% %, MgO 6wt%~7wt%, MnO ₂ wt%~3wt%;

Step 5, drying:

After the ball milling is completed, put it into a constant temperature drying oven, react and dry at a temperature of 50° C. for 20 minutes, and obtain the steel slag material doped with the ammonium salt-graphene composite activator.

The steel slag material prepared in Example 1 and P.O 42.5 cement are mixed according to the ratio of steel slag material: P.O 42.5 cement = 3:7 by mass, and maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 43.5Mpa, and the activity index is 91.3%. According to the test standard of the Rayleigh clip method in GB/T1346-2011, the stability of the test is reduced to 1mm.

Example 2

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 35 wt%, the mass fraction of ammonium bicarbonate is 35 wt%, and the mass fraction of ammonium sulfate is 30 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 2 and P.O 42.5 cement are mixed according to the mass ratio of steel slag material: P.O 42.5 cement = 3:7, and are maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 42.4Mpa, and the activity index is 89.1%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 2mm.

Example 3

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 20 wt%, the mass fraction of ammonium bicarbonate is 60 wt%, and the mass fraction of ammonium sulfate is 20 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 3 and P.O 42.5 cement are mixed according to the mass ratio of steel slag material: P.O 42.5 cement = 3:7, and are maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 43.2Mpa, and the activity index is 90.8%. According to the test standard of the Rayleigh clip method in GB/T1346-2011, the stability of the test is reduced to 1mm.

Example 4

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 25 wt%, the mass fraction of ammonium bicarbonate is 55 wt%, and the mass fraction of ammonium sulfate is 20 wt%. All the other processes are identical to Example 1.

According to the GB/T 17671-2021 test standard, the steel slag material prepared in Example 4 and P.O 42.5 cement were mixed according to the mass ratio of steel slag material: P.O 42.5 cement = 3:7, and cured in a water culture environment at 20°C After 28 days, the highest compressive strength can reach 43.9Mpa, and the activity index is 92.2%. According to the test standard of the Rayleigh clip method in GB/T1346-2011, the stability of the test is reduced to 0.5mm.

Example 5

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 25 wt%, the mass fraction of ammonium bicarbonate is 50 wt%, and the mass fraction of ammonium sulfate is 25 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 5 and P.O 42.5 cement are mixed according to the mass ratio of steel slag material: P.O 42.5 cement = 3:7, and are maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 43.4Mpa, and the activity index is 91.1%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 1mm.

Example 6

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 30 wt%, the mass fraction of ammonium bicarbonate is 55 wt%, and the mass fraction of ammonium sulfate is 15 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 6 and P.O 42.5 cement are mixed according to the ratio of steel slag material: P.O 42.5 cement = 3:7 by mass, and maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 43.7Mpa, and the activity index is 91.8%. According to the test standard of the Rayleigh clip method in GB/T1346-2011, the stability of the test is reduced to 1mm.

Example 7

Compared with Example 1, this embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 20 wt%, the mass fraction of ammonium bicarbonate is 55 wt%, and the mass fraction of ammonium sulfate is 25 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 7 and P.O 42.5 cement are mixed according to the ratio of steel slag material: P.O 42.5 cement = 3:7 by mass, and maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 43.7Mpa, and the activity index is 91.8%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 1mm.

Example 8

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 25 wt%, the mass fraction of ammonium bicarbonate is 45 wt%, and the mass fraction of ammonium sulfate is 30 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 8 and P.O 42.5 cement are mixed according to the ratio of steel slag material: P.O 42.5 cement = 3:7 by mass, and maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 43.1Mpa, and the activity index is 90.6%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 2mm.

Example 9

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 30 wt%, the mass fraction of ammonium bicarbonate is 45 wt%, and the mass fraction of ammonium sulfate is 25 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 9 and P.O 42.5 cement are mixed according to the ratio of steel slag material: P.O 42.5 cement = 3:7 by mass, and maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 42.8Mpa, and the activity index is 89.9%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 2mm.

Example 10

Compared with Example 1, the present embodiment differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 35 wt%, the mass fraction of ammonium bicarbonate is 45 wt%, and the mass fraction of ammonium sulfate is 20 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Example 10 and P.O 42.5 cement are mixed according to the ratio of steel slag material: P.O 42.5 cement = 3:7 by mass, and maintained in an aquaculture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 43.2Mpa, and the activity index is 90.8%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 2mm.

Comparative example 1

Compared with Example 1, this comparative example differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 35 wt%, the mass fraction of ammonium bicarbonate is 30 wt%, and the mass fraction of ammonium sulfate is 35 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Comparative Example 1 and P.O 42.5 cement were mixed according to the mass ratio of steel slag material: P.O 42.5 cement = 3:7, and maintained in a water culture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 41.4Mpa, and the activity index is 86.9%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 2mm.

Comparative example 2

Compared with Example 1, this comparative example differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 40 wt%, the mass fraction of ammonium bicarbonate is 30 wt%, and the mass fraction of ammonium sulfate is 20 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Comparative Example 2 and P.O 42.5 cement are mixed according to the mass ratio of steel slag material: P.O 42.5 cement = 3:7, and are maintained in a water culture environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, its compressive strength can reach 40.6Mpa, and its activity index is 85.2%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 2mm.

Comparative example 3

Compared with Example 1, this comparative example differs in that: in the ammonium salt, the mass fraction of ammonium chloride is 45 wt%, the mass fraction of ammonium bicarbonate is 30 wt%, and the mass fraction of ammonium sulfate is 25 wt%. All the other processes are identical to Example 1.

The steel slag material prepared in Comparative Example 3 and P.O 42.5 cement are mixed according to the ratio of steel slag material: P.O 42.5 cement = 3:7 in mass ratio, and maintained in an aquatic environment at 20°C according to the GB/T 17671-2021 test standard After 28 days, the highest compressive strength can reach 40.2Mpa, and the activity index is 85.4%. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 2mm.

Comparative example 4

The original steel slag material and P.O 42.5 cement are mixed according to the ratio of original steel slag material: P.O 42.5 cement = 3:7 by mass, and maintained in a water culture environment at 20°C for 28 days according to the GB/T 17671-2021 test standard. The composition of steel slag is: 45wt%-56wt% of CaO, 10wt%-15wt% of SiO2, 1.8wt%-4wt% of Al2O3, 20wt%-28wt% of Fe2O3, 6wt%-7wt% of MgO, and 3wt% of MnO2. Its compressive strength can reach up to 32.5Mpa, and its activity index is 68.2%. According to the test standard of the Rayleigh clip method in GB/T1346-2011, the stability is detected to be reduced to 2mm.

Comparative example 5

According to the GB/T 17671-2021 test standard, the P.O 42.5 cement is cured in an aquatic environment at 20°C for 28 days, and its compressive strength can reach a maximum of 47.6Mpa. According to the test standard of Rayleigh clip method in GB/T1346-2011, its stability is 0.5mm.

Table 1

Table 1 shows the compressive strength, activity index and stability of the samples of Examples 1-10 and Comparative Examples 1-5. As can be seen from Table 1, according to the detection result of embodiment and comparative example, when the massfraction of ammonium bicarbonate in three kinds of ammonium is 55wt%, anti-pressure, activity index, stability effect are all better, and when the ammonium bicarbonate The compressive properties begin to deteriorate when the mass fraction increases or decreases.

Claims (3)

1. The ammonium salt-graphene composite excitant is characterized by comprising ammonium salt and graphene, wherein the ammonium salt is a compound of ammonium chloride, ammonium bicarbonate and ammonium sulfate, the graphene is multilayer graphene, and the mass ratio of the ammonium salt to the graphene is (10-15): 1, a step of;

in the ammonium salt, the mass fraction of the ammonium chloride is 20-35 wt%, the mass fraction of the ammonium bicarbonate is 35-65 wt%, and the mass fraction of the ammonium sulfate is 15-30 wt%.

2. The steel slag material doped with the ammonium salt-graphene composite activator is characterized by comprising the ammonium salt-graphene composite activator and steel slag according to the mass ratio of 1: (10-30).

3. The preparation method of the steel slag material doped with the ammonium salt-graphene composite activator is characterized by comprising the following steps of:

step 1, weighing raw materials:

weighing three ammonium salts of ammonium chloride, ammonium bicarbonate and ammonium sulfate as raw materials according to the proportion of '20-35 wt% of ammonium chloride, 35-65 wt% of ammonium bicarbonate and 15-30 wt% of ammonium sulfate';

step 2, ball milling:

putting the raw materials weighed in the step 1 into a ball mill for ball milling treatment, wherein the ball milling rotating speed is 30-40 r/min, the ball milling time is 5min, and obtaining an ammonium salt compound after ball milling is completed;

step 3, mixing with graphene:

and (2) mixing the ammonium salt compound obtained in the step (2) with graphene according to the mass ratio of (10-15): 1, ball milling, wherein the ball milling rotating speed is 200r/min, the ball milling time is 10min, and the ammonium salt-graphene composite excitant is obtained after the ball milling is completed;

step 4, mixing with steel slag:

adding the ammonium salt-graphene composite activator obtained in the step 3 into steel slag, wherein the mass ratio of the ammonium salt-graphene composite activator to the steel slag is 1: (10-30); then, putting the mixture into a ball mill for ball milling treatment, wherein the ball milling rotating speed is 30-40 r/min, and the ball milling time is 10min;

step 5, drying:

and after ball milling, placing the mixture into a constant-temperature drying oven, and drying the mixture for 20 minutes at the temperature of 40-50 ℃ to obtain the ammonium salt-graphene composite excitant doped steel slag material.