CN111847943A - A kind of slag micropowder and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of comprehensive utilization of resources, and discloses a slag micropowder and a preparation method thereof. The method comprises the following steps: (1) mixing the hot slag of the titanium extraction tailings with water, and then performing dehydration treatment to obtain crude dechlorination tailings; (2) mixing the crude dechlorination tailings obtained in step (1) with Fe-containing tailings The paddle body of ³⁺ is mixed, then roasting to obtain deep dechlorination residue; (3) the deep dechlorination residue obtained in step (2) is mixed with activator and reinforcing agent, and then ground to a specific surface area greater than or equal to 400m ² / kg; this method adopts Fe ³⁺ paddle body for dechlorination, and improves the technological process, improves the dechlorination effect of titanium extraction tailings, can not only produce slag fine powder that meets the requirements of national standards, but also reduces the production cost, and realizes the extraction of slag. The efficient and comprehensive utilization of titanium tailings resources and the recovery of ferric chloride and other resources are in line with the current circular economy policy requirements.

Description

A kind of slag micropowder and preparation method thereof

technical field

The invention relates to the technical field of comprehensive utilization of resources, in particular to a slag micropowder and a preparation method thereof.

Background technique

The content of silicate glass in the titanium tailing slag is more than 90%, and it has excellent pozzolanic activity. If the chloride ion in the tailing can be effectively removed, active materials such as high-grade slag powder can be developed (currently the national standard requires that it be applied to cement The chlorine content of granulated blast furnace slag powder and concrete is less than 0.06%).

At present, the pyrolytic dechlorination process is used for the titanium extraction tailings. When the temperature exceeds 900 °C, the chlorine in the titanium extraction tailings can be effectively removed, but a large amount of vitreous body in the titanium extraction tailings is crystallized and the activity is lost. The slag remains active, and the roasting and dechlorination temperature cannot exceed 700 °C.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of slag micropowder and a preparation method thereof in order to overcome the problems of low dechlorination effect of titanium extraction tailings and reduced activity in the dechlorination process existing in the prior art.

In order to achieve the above object, one aspect of the present invention provides a method for preparing slag micropowder, the method comprising the following steps:

(1) mixing the titanium tailings hot slag and water, then carrying out dehydration treatment to obtain crude dechlorination tailings;

(2) the crude dechlorination tailings obtained in step (1) are mixed with the paddle body containing ^Fe , then roasting is carried out to obtain deep dechlorination residues;

(3) the deep dechlorination residue obtained in step (2) is mixed with an activator and a reinforcing agent, and then ground to a specific surface area greater than or equal to 400m ² /kg;

Wherein, in step (1), the chlorine content in the crude dechlorination tailings is 0.3-0.5% by weight, and the moisture content is 15-20%.

Preferably, in step (1), the temperature of the titanium-extracted tailings hot slag is 500-600° C., the chlorine content is 2-4% by weight, and the particle size is less than 0.02 mm.

Preferably, in step (1), the mass ratio of the titanium extraction tailings hot slag to water is 1:2-5.

Preferably, in step (1), the dehydration treatment is carried out in a vacuum belt filter; after the dehydration treatment, water is sprayed on the upper part of the belt filter for washing twice, and the liquid-solid ratio of the washing is 0.2-2: 1.

Preferably, in step (2), the Fe ³⁺ concentration in the Fe ³⁺ -containing paddle is 20-50% by weight.

Preferably, in step (2), the mass ratio of the crude dechlorination tailings and the paddle body containing Fe ³⁺ is 1:0.05-0.3.

Preferably, in step (2), the roasting temperature is 600-700° C., the roasting time is 30-120 min, and the roasting atmosphere is an oxidizing atmosphere.

Preferably, in step (2), the chlorine content of the deep dechlorination residue is less than or equal to 0.06% by weight.

Preferably, in step (3), the mass ratio of the deep filter residue, the activator and the enhancer is 1:0.002-0.02:0.01-0.1.

The second aspect of the present invention provides a slag micropowder prepared by the above method.

The method for preparing slag micropowder of the present invention utilizes the paddle body containing Fe ³⁺ for dechlorination, improves the technological process, improves the dechlorination effect of the tailings of titanium extraction, and can produce slag micropowder that meets the requirements of national standards, At the same time, the production cost is reduced, and the efficient and comprehensive utilization of titanium tailings resources is realized, and resources such as ferric chloride are recovered, which meets the current green chemical requirements.

Description of drawings

Fig. 1 is the process flow diagram of preparing slag micropowder according to the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

A first aspect of the present invention provides a method for preparing slag micropowder, the process flow diagram of which is shown in Figure 1, and the method comprises the following steps:

(1) mixing the titanium tailings hot slag and water, then carrying out dehydration treatment to obtain crude dechlorination tailings;

(2) the crude dechlorination tailings obtained in step (1) are mixed with the paddle body containing ^Fe , then roasting is carried out to obtain deep dechlorination residues;

(3) the deep dechlorination residue obtained in step (2) is mixed with an activator and a reinforcing agent, and then ground to a specific surface area greater than or equal to 400m ² /kg;

Wherein, in step (1), the chlorine content in the crude dechlorination tailings is 0.3-0.5% by weight, and the moisture content is 15-20%.

In the method of the present invention, the titanium-extracted tailing hot slag is a by-product after high-temperature carbonization and low-temperature chlorination of titanium-containing blast furnace slag, and the main components contain 25-30% by weight of calcium oxide, 20- 25 wt% silica, 5-10 wt% titania, 15-20 wt% alumina, 5-10 wt% magnesium oxide, 2-4 wt% chloride, 5-8 wt% of free carbon.

In the method of the present invention, there is no special requirement for the source of the Fe ^{3+-containing} paddle, and it can be purchased or homemade. In a specific embodiment, the specific configuration step of the Fe ^{3+-containing} paddle is mixing ferric sulfate and water and/or mixing ferrous sulfate and water, and blowing compressed air inward to perform aeration oxidation treatment.

In the method of the present invention, the activator is an alkali activator, which is used to improve the activity of the slag micropowder. In a specific embodiment, the activator is calcium oxide or calcium hydroxide.

In the method of the present invention, the reinforcing agent is used to improve the strength of the slag micropowder, and there is no special requirement for the selection of the reinforcing agent, which can be a conventional choice in the field. In a specific embodiment, the reinforcing agent is gypsum.

In the method of the present invention, in step (3), there is no special requirement for the selection of the grinding equipment, and it can be a conventional selection in the field. In a specific embodiment, the grinding is carried out in a ball mill or a vertical mill.

In the method of the present invention, in step (1), the temperature of the hot slag from the titanium tailings is 500-600°C. Specifically, the temperature of the titanium tailings hot slag may be 500°C, 510°C, 550°C, 570°C or 600°C.

In the method of the present invention, in step (1), the chlorine content of the titanium extraction tailings is 2-4% by weight, and the particle size is less than 0.02 mm.

In the method of the present invention, in step (1), the mass ratio of the hot slag of the titanium extraction tailings to water is 1:2-5. In a specific embodiment, the mass ratio of the titanium extraction tailing hot slag to water may be 1:2, 1:3, 1:4 or 1:5.

In the method of the present invention, in step (1), in a preferred case, the dehydration treatment is carried out in a vacuum belt filter, and after the dehydration treatment, water is sprayed on the upper part of the belt filter for washing twice, so The washing conditions are as follows: the liquid-solid ratio of washing is 0.2-2:1. In a specific embodiment, the liquid-solid ratio of the washing may be 0.2:1, 0.5:1, 0.7:1, 1:1, 1.5:1 or 2:1.

In the method of the present invention, in step (1), the chlorine content of the crude dechlorination tailings is 0.3-0.5% by weight. Preferably, the chlorine content of the crude dechlorination tailings is 0.35-0.5% by weight, and further preferably, the chlorine content of the crude dechlorination tailings is 0.37-0.48% by weight.

In the method of the present invention, in step (1), the moisture content of the crude dechlorination tailings is 15-20%. Preferably, the moisture content of the crude dechlorination tailings is 16-20%.

In the method of the present invention, in step (2), the conditions of the Fe ^{3+-containing paddle are as follows: the Fe 3+ concentration} is 20-50% by weight. In specific embodiments, the concentration of Fe ³⁺ may be 20 wt %, 25 wt %, 30 wt %, 40 wt % or 50 wt %.

In the method of the present invention, in step (2), the mass ratio of the rough demineralized slag tailings and the paddle body containing Fe ³⁺ is 1:0.05-0.3. In a specific embodiment, the mass ratio of the rough de-slag tailings and the paddle body containing Fe ³⁺ may be 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25 or 1:0.3.

In the method of the present invention, in step (2), the calcination conditions are: the temperature is 600-700°C. In specific embodiments, the calcination temperature may be 600°C, 650°C or 700°C.

In the method of the present invention, in step (2), the conditions of the roasting are as follows: the time is 30-120 min. In a specific embodiment, the roasting temperature may be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min.

In the method of the present invention, in step (2), the roasting conditions are: the roasting atmosphere is an oxidizing atmosphere. In specific embodiments, the firing atmosphere may be oxygen, air or ozone.

In the method of the present invention, in step (2), the condition of the deep dechlorination residue is that the chlorine content is less than or equal to 0.06% by weight. Preferably, the chlorine content of the deep dechlorination residue is 0.045-0.06% by weight.

In the method of the present invention, in step (3), the mass ratio of the deep filter residue, the activator and the enhancer is 1:0.002-0.02:0.01-0.1. In a specific embodiment, the mass ratio of the deep filter residue, the activator and the enhancer may be 1:0.005:0.04, 1:0.01:0.05, 1:0.02:0.1.

In the method of the present invention, in step (3), in a preferred case, the grinding is fine to a specific surface area of 400-500 m ² /kg.

The second aspect of the present invention provides a slag micropowder prepared by the above method.

The method for preparing slag micropowder of the present invention has the following advantages:

(1) Dechlorination using the paddle containing Fe ³⁺ , optimizing the process flow, so that the chlorine in the titanium extraction tailings can be removed to less than 0.06% by weight, and the activity index can reach more than 95%, which meets the standard requirements.

(2) The overall process is compact, the process is simple, and the production cost is low.

(3) It can realize the efficient and comprehensive utilization of titanium tailing slag resources, and at the same time recover ferric chloride and other resources, which meets the current requirements of green chemical industry.

The present invention will be described in detail through the following examples, but the protection scope of the present invention is not limited thereto.

Example 1

(1) Mix the 550°C titanium tailing hot slag (chlorine content is 2-4% by weight, particle size < 0.02mm) and water in a mass ratio of 1:2, and then use a vacuum belt filter for dehydration treatment, then The upper part of the belt filter is sprayed with water for two washings, and the washing liquid-solid ratio is 0.2:1 to obtain crude dechlorination tailings with a chlorine content of 0.48% by weight and a moisture content of 18%;

(2) ferric sulfate and water are mixed, and the slurry with ^Fe concentration of 30% by weight is configured to be 30% by weight, and the crude dechlorination tailings obtained in step (1) and the paddle containing ^Fe are in a mass ratio of 1:0.3 Mixing, then calcining in air at 700 ° C, the calcining time is 30min, to obtain a deep dechlorination residue with a chlorine content of 0.06% by weight;

(3) be 1: 0.01: 0.05 mixing with step ( ² ) gained deep dechlorination residue with calcium hydroxide and gypsum by mass ratio, grind to specific surface area 420m /kg with ball mill or vertical mill, obtain slag micropowder A1 .

Example 2

(1) Mix the 510°C titanium tailing hot slag (chlorine content is 2-4% by weight, particle size < 0.02mm) and water in a mass ratio of 1:3, then use a vacuum belt filter for dehydration treatment, and then The upper part of the belt filter is sprayed with water for two washings, and the washing liquid-solid ratio is 1:1 to obtain crude dechlorination tailings with a chlorine content of 0.36% by weight and a moisture content of 16%;

(2) mixing ferrous sulfate and water, blowing compressed air inwards to carry out exposure oxidation, and configuring into a slurry with Fe ³⁺ concentration of 25% by weight, and mixing the crude dechlorination tailings obtained in step (1) with Fe ³⁺ The paddle of ⁺ is mixed by mass ratio of 1:0.05, and then calcined in air at 600 ° C, and the calcination time is 120 min to obtain a deep dechlorination residue with a chlorine content of 0.059% by weight;

(3) be 1: 0.02: 0.1 mixing with step (2) gained deep dechlorination residue with calcium hydroxide and gypsum by mass ratio, with ball mill or vertical mill grinding to specific surface area 450m ² /kg, obtain slag micropowder A2 .

Example 3

(1) Mix the 570°C titanium tailing hot slag (chlorine content is 2-4% by weight, particle size < 0.02mm) and water in a mass ratio of 1:5, and then use a vacuum belt filter for dehydration treatment, then The upper part of the belt filter is sprayed with water for two washings, and the washing liquid-solid ratio is 2:1 to obtain a crude dechlorination tailings with a chlorine content of 0.32% by weight and a moisture content of 20%;

(2) Mixing ferrous sulfate and water, blowing compressed air inwards to carry out exposure oxidation, configuring into a slurry with Fe ³⁺ concentration of 40% by weight, and mixing the crude dechlorination tailings obtained in step (1) with Fe ³⁺ The paddle of ⁺ is mixed by mass ratio of 1:0.15, and then roasted in air at 650 ° C, and the roasting time is 90min, to obtain a deep dechlorination residue with a chlorine content of 0.047% by weight;

(3) be 1: 0.005: 0.04 mixing with step (2) gained deep dechlorination residue with calcium hydroxide and gypsum by mass ratio, with ball mill or vertical mill grinding to specific surface area 440m ² /kg, obtain slag micropowder A3 .

Comparative Example 1

The implementation was carried out according to the method described in Example 1, except that the paddle body containing Fe ³⁺ was replaced with a paddle body containing Fe ²⁺ with the same concentration to obtain the slag fine powder D1.

Comparative Example 2

According to the method described in Example 1, the difference is that the concentration of Fe ³⁺ in the paddle containing Fe ³⁺ is reduced to 10 wt % to obtain slag fine powder D2.

Comparative Example 3

According to the method described in Example 3, the difference is that the roasting temperature is increased to 900° C. to obtain slag fine powder D3.

Test Example 1

The chlorine content and activity index of the slag micropowder prepared in Example 1-3 and Comparative Example 1-3 were measured by the method reported in the national standard GB/T18046-2008, and the test results are shown in Table 1.

Table 1

It can be seen from the results in Table 1 that by using the method of the present invention, the slag micropowder prepared in Examples 1-3 meets the national standard of S95 grade slag micropowder.

The preferred embodiments of the present invention have been described above in detail, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solutions of the present invention, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in the present invention. All belong to the protection scope of the present invention.

Claims (10)

1. A method for producing fine slag powder, characterized by comprising the steps of:

(1) mixing the titanium extraction tailings hot slag with water, and then performing dehydration treatment to obtain coarse dechlorination tailings;

(2) will be provided withThe coarse dechlorination tailings obtained in the step (1) contain Fe³⁺Mixing the slurry, and then roasting to obtain deep dechlorinated slag;

(3) mixing the deep dechlorination slag obtained in the step (2) with an exciting agent and a reinforcing agent, and then grinding the mixture until the specific surface area is more than or equal to 400m²/kg；

Wherein in the step (1), the chlorine content in the coarse dechlorination tailings is 0.3-0.5 wt%, and the water content is 15-20%.

2. The method for preparing slag micropowder according to claim 1, wherein in the step (1), the temperature of the titanium extraction tailings hot slag is 500-600 ℃, the chlorine content is 2-4 wt%, and the particle size is less than 0.02 mm.

3. The method for preparing slag micropowder according to claim 1, wherein in step (1), the mass ratio of the titanium extraction tailings hot slag to water is 1: 2-5.

4. The method for producing fine slag powder according to claim 1, wherein in the step (1), the dehydration treatment is performed in a vacuum belt filter;

preferably, after the dehydration treatment, the washing is carried out twice by spraying water on the upper part of the belt filter, and the liquid-solid ratio of the washing is 0.2-2: 1.

5. the method for producing slag micropowder according to claim 1, wherein in step (2), the Fe-containing slag micropowder^{3 +}Fe in the slurry³⁺The concentration is 20-50 wt%.

6. The production method of fine slag powder according to claim 1, wherein in the step (2), the coarse dechlorinated tailing is supplied with a raw slag containing Fe³⁺The mass ratio of the paddle body is 1: 0.05-0.3.

7. The method for preparing slag micropowder according to claim 1, wherein in the step (2), the roasting temperature is 600-700 ℃, the roasting time is 30-120min, and the roasting atmosphere is an oxidizing atmosphere.

8. The production method of fine slag powder according to claim 1, wherein in the step (2), the chlorine content of the deep dechlorinated slag is 0.06 wt.% or less.

9. The production method of fine slag powder according to claim 1, wherein in step (3), the mass ratio of the deep dechlorinated slag, the exciting agent, and the reinforcing agent is 1: 0.002-0.02: 0.01-0.1.

10. Fine slag powder produced by the method according to any one of claims 1 to 9.

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