CN114163157A

CN114163157A - Process for producing slag micropowder admixture by slag dilution and application

Info

Publication number: CN114163157A
Application number: CN202111604145.9A
Authority: CN
Inventors: 柏森; 郭军; 穆怀富; 毕建国; 赵一鹏; 李晓峰; 薛金柱; 郑海东; 王志强
Original assignee: Jifei Ferroalloy Co ltd
Current assignee: Jifei Ferroalloy Co ltd
Priority date: 2021-12-24
Filing date: 2021-12-24
Publication date: 2022-03-11
Anticipated expiration: 2041-12-24
Also published as: CN114163157B

Abstract

The invention discloses a process for producing slag micropowder admixture by slag dilution, which comprises the steps of S1, manganese-silicon slag treatment; s2, treating low-carbon ferrochromium slag ash; and S3, preparing the slag micro powder admixture. The invention also discloses application of the slag micro powder admixture, which is used for admixture of cement and used as a building material. The manganese-silicon slag and the low-carbon ferrochromium slag ash are firstly used for slag micro powder production and micro powder preparation in the cement industry, and can be used as a cement admixture after dilution treatment and proportioning with an alkali activator and an acid activator, and after the micro powder is doped, the compression strength and the flexural strength of the cement meet the requirements of S95-grade cement micro powder.

Description

Process for producing slag micropowder admixture by slag dilution and application

The technical field is as follows:

the invention relates to a process for producing building materials and application thereof, in particular to a process for producing slag micropowder admixture by slag depletion and application thereof.

Background art:

the ferroalloy manganese-silicon slag is waste slag generated in the process of producing manganese-silicon-iron alloy by smelting raw materials such as manganese-silicon ore, lime, coke and the like at high temperature, and contains 20-21% of CaO and SiO₂About 39-42% of Al₂O₃About 14 to 16% by weight, and about 7 to 8% by weight of MnO. The slag is acid slag with main chemical components of iron deficiency, low CaO and SiO₂High MnO content, low slag quality coefficient and low activity (the quality coefficient is a main method for evaluating the quality of slag by chemical component analysis, and the national standard GB/T203 of China stipulates that the quality coefficient K of granulated blast furnace slag is (CaO + MgO + Al)₂O₃)/(SiO₂+ MnO + TiO), the mass coefficient K reflects the proportional relationship between the active components and the less active and inactive components in the slag, the higher the mass coefficient K value, the higher the slag activity).

The low-carbon ferrochrome slag ash is formed by pulverizing low-carbon ferrochrome slag under a natural cooling condition, is waste slag generated when the low-carbon ferrochrome is produced by high-temperature smelting of raw materials such as chromium ore, silicon-chromium alloy, lime and the like, and contains 50-52% of high-content CaO and SiO₂About 28-29% of Al₂O₃About 7 to 8% of Cr₂O₃About 3.6 to 4.5%. The low-carbon ferrochromium slag ash is alkaline ash, and has a high mass coefficient calculated according to chemical components. However, the active beta-CaO is transformed into inactive gamma-CaO substance under the condition of slow natural cooling and the like of CaO, so that the real activity of the slag ash is not high.

The manganese-silicon slag and the low-carbon ferrochrome slag ash produced by domestic ferroalloy enterprises are basically used as inert substance fillers in the cement industry. However, the two types of slag have low activity and contain a large amount of difficult-to-grind substances (the difficult-to-grind substances in the manganese-silicon slag are high-silicon vitreous bodies, which results in that the grinding time is increased in the grinding process, meanwhile, the high-silicon vitreous bodies are inactive substances to influence the slag activity, the difficult-to-grind substances in the low-carbon ferrochrome slag ash are low-carbon ferrochrome particles, which cannot be ground to influence the grinding fineness), the difficult-to-grind substances are limited by regional conditions in an inner Mongolia region and are not approved by the local cement industry, the difficult-to-grind substances are basically solid waste residues, and the difficult-to-grind substances are managed by the enterprise capital government to be discharged and buried.

The invention content is as follows:

the first purpose of the invention is to provide a process for producing slag micropowder admixture by slag depletion, which is to remove inert substances and difficult-to-grind substances influencing activity in manganese-silicon slag and low-carbon ferrochrome slag ash; enriching valuable minerals for recycling (the valuable minerals in the manganese-silicon slag are mainly MnO which can be recycled, and meanwhile, the MnO is an inert substance which influences the activity in the slag, the national standard GB/T203 of China stipulates that the MnO is less than 4%, if the MnO content in the slag is more than 4%, the activity of the slag can be seriously influenced, the substances which are difficult to grind in the low-carbon ferrochrome slag ash are low-carbon ferrochrome grains, and the low-carbon ferrochrome grains can be recycled and reused as the valuable minerals); the slag quality coefficient is improved to produce slag micropowder. The waste residue can be comprehensively utilized, and the environmental protection problem of waste residue discharge is solved.

The second purpose of the invention is to provide an application of slag micropowder admixture in slag depletion production.

The first purpose of the invention is implemented by the following technical scheme: a process for producing slag micropowder admixture by slag depletion comprises the following steps

S1, manganese-silicon slag treatment: carrying out primary grinding on manganese-silicon slag generated in the production of manganese-silicon alloy through pre-grinding, then carrying out air separation classification to remove substances difficult to grind and partial inert substances, carrying out magnetic separation on the manganese-silicon slag subjected to air separation classification under the strong magnetic condition, and carrying out magnetic separation on valuable mineral enriched slag; carrying out micro-grinding on the manganese-silicon slag subjected to magnetic separation in a high-fine ball mill to obtain silicon-manganese slag powder meeting the use standard of the cement industry for later use;

s2, treating low-carbon ferrochrome slag ash: feeding the low-carbon ferrochrome slag ash into a powder concentrator, and adjusting the air speed of the powder concentrator to perform fineness classification on the low-carbon ferrochrome slag ash so as to obtain valuable minerals difficult to grind and ferrochrome slag pre-prepared materials;

s3, preparing the slag micro powder admixture: mixing silicomanganese slag powder obtained in the S1. manganese-silicon slag treatment and ferrochrome slag pre-prepared materials obtained in the S2. low-carbon ferrochrome slag ash treatment according to the weight ratio of (7-9) to (1-3), and mixing the mixture with an alkali activator and an acid activator according to the weight ratio of (85-90): (3-5): and (7-10) mixing and grinding the materials according to the mass ratio to obtain the cement admixture.

Further, in the S1. manganese-silicon slag treatment, the grinding fineness of the primary grinding is classified as follows: more than or equal to 80 meshes and 97 percent; not less than 120 meshes and 90 percent; not less than 200 meshes and 50 percent.

Further, in the S1. manganese-silicon slag treatment, the wind speed is adjusted to be divided into two levels of fineness below 200 meshes and fineness above 200 meshes during air separation and classification, and the fineness above 200 meshes is used as a preparation material for preparing the slag micro powder.

Further, in the S1 manganese-silicon slag treatment, the magnetic separation strength is 5000-8000 GS.

Further, in the S1 manganese-silicon slag treatment, the micro-grinding grade is S95 grade, namely the specific surface area is 500m²More than g.

Further, in the S2. low-carbon ferrochrome slag ash treatment, the wind speed of the separator is adjusted into two levels of fineness below 200 meshes and fineness above 200 meshes, and the fineness above 200 meshes is used as a ferrochrome slag preparation material.

Further, the acid excitant is desulfurized gypsum.

Further, the alkali-activator is portland cement clinker.

The second object of the present invention is implemented by the following embodiments: the application of slag depletion in producing superfine slag powder as admixture for cement.

Furthermore, the blending amount of the slag micro powder admixture accounts for 20-50% of the weight of the cement.

The invention has the advantages that:

1. the manganese-silicon slag and the low-carbon ferrochromium slag ash are firstly used for slag micro powder production and micro powder preparation in the cement industry, and can be used as a cement admixture after dilution treatment and proportioning with an alkali activator and an acid activator, and after the micro powder is doped, the compression strength and the flexural strength of the cement meet the requirements of S95-grade cement micro powder.

2. From the aspect of environmental protection, the recycling of metallurgical wastes creates great value, simultaneously saves the use of cement clinker, and reduces the environmental pollution caused by cement production.

3. After the depletion treatment of the manganese-silicon slag and the low-carbon ferrochrome slag, valuable minerals are well purified, and especially the effect of the chute and table combined method is optimal. The manganese metal grade is improved by 15.08-31%, and the yield is 1.0-3.0%. The grade meets the requirement of re-entering the furnace for smelting and ore blending. In this way, it is fully demonstrated that the method is very effective for purifying valuable minerals.

Description of the drawings:

in order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a process flow diagram for slag fines depletion production of a slag fines admixture according to the present invention.

The specific implementation mode is as follows:

the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the experiment carried out in a certain ferroalloy manufacturing enterprise of inner Mongolia in the embodiment, the chemical composition test analysis results of the manganese-silicon slag are listed in Table 1, and the chemical composition test analysis results of the low-carbon ferrochrome slag ash are listed in Table 2.

TABLE 1 chemical composition analysis result table for Mn-Si slag

TABLE 2 chemical composition analysis result table of low-carbon ferrochromium slag ash

Cr₂O₃	SiO₂	FeO	Al₂O₃	CaO	MgO	Total of
							4.38	28.93	0.720	6.44	47.69	8.85	97.28

The mass coefficient K and the basicity coefficient Mo are calculated as follows:

mass coefficient K ═ CaO + MgO + Al₂O₃)/(SiO₂+MnO+TiO)

Basicity coefficient Mo ═ CaO + MgO)/(SiO₂+Al₂O₃)

The national standard GB/T203 of China specifies that the mass coefficient K is more than or equal to 1.2; mo >1 represents alkaline slag; mo ═ 1 represents neutral slag; mo <1 represents acidic slag;

as can be seen from table 1, the K of the mn-si slag used in this example is 44.35/50.14 is 0.88< 1.2; mo is 24.69/60.82 is 0.41; therefore, the manganese-silicon slag in the embodiment is acid slag, the mass coefficient is low, and the activity of the manganese-silicon slag is low.

As can be seen from table 2, K of the low-carbon ferrochromium slag ash used in this example is 65.81/33.208 is 1.98> 1.2; mo is 58.48/35.87 is 1.63; it can be seen that the low-carbon ferrochrome slag ash in the embodiment is alkaline slag, the mass coefficient calculated by chemical components is higher, but the actual activity is not high.

The two types of slag are treated as follows:

1. separating hard-to-grind substance from low-carbon ferrochrome slag ash

The low-carbon ferrochrome slag ash is loaded into a hopper and is sent into a powder concentrator by a belt conveyor, and the air speed of the powder concentrator is adjusted to carry out fineness classification on the low-carbon ferrochrome slag ash, wherein the low-carbon ferrochrome slag ash is divided into two grades of fineness of less than 200 meshes and more than 200 meshes; the material below 200 meshes is valuable mineral, i.e. difficult-to-grind material, and the material above 200 meshes is used as a preparation material for preparing the slag micro powder.

The results of preliminary assay analysis of fine slag powder are shown in Table 3.

TABLE 3 chemical component analysis table for low-carbon ferrochromium slag powder sample after separation of hard-to-grind substances

Cr₂O₃	SiO₂	Al₂O₃	FeO	CaO	MgO	Total of	Yield of
								3.66	28.38	8.22	0.695	48.25	10.31	96.60	97％

Calculation of Mass coefficient K and basicity coefficient Mo

K＝66.78/32.73＝2.04>1.2；Mo＝58.56/32.04＝1.83>1。

2. Separating hard-to-grind substance from manganese-silicon slag

Drying manganese-silicon slag, feeding into a dry-type ball mill by a disc feeder for pre-grinding, wherein the fineness of the pre-ground slag is 80 meshes, so that valuable minerals can be fully dissociated in a single body, feeding the pre-ground slag into a powder concentrator by a belt conveyor for fineness classification, and feeding easily ground substances (CaO, MgO and Al)₂O₃) Separating the objects difficult to grind (high-silicon glass body) and part of valuable minerals (MnO), and dividing the objects into objects less than 120 meshes (difficult to grind (high-silicon glass body) and part of valuable minerals (MnO)) and objects more than 120 meshes (easy to grind (CaO, MgO, Al)₂O₃) And partial value minerals (MnO)) two grades of fine slag.

And then feeding the slag with the granularity of more than 120 meshes into a magnetic separator with the magnetic field intensity of 7000GS for magnetic separation of valuable minerals (MnO), and obtaining the prepared material for preparing the slag micro powder after the magnetic separation.

Directly feeding the magnetically separated slag and the winnowing separated slag into a mechanical stirring cylinder to prepare ore pulp with the ore pulp concentration of 35% -45%, feeding the ore pulp into a gravity separation chute by a slag pulp pump to perform primary enrichment of valuable minerals, and directly feeding the primarily enriched valuable minerals into a gravity separation table concentrator to be concentrated so as to finally achieve the aim of recycling again.

The test results of the fine slag powder preparation are shown in Table 4.

TABLE 4 chemical component analysis table for slag micropowder

Mn	SiO2	FeO	Al2O3	CaO	MgO	Yield of
							5.08	37.21	0.200	18.82	22.93	3.43	70％

A mass coefficient K; calculation of basicity coefficient Mo

K＝45.18/42.29＝1.068<1.2；Mo＝26.36/56.03＝0.47

3. The processed manganese-silicon slag and the processed low-carbon ferrochrome slag ash are mixed according to the mass ratio of 7:3, and the mixture is tested and analyzed, which is shown in Table 5.

TABLE 5 analysis table for chemical composition assay of mixture

Calculation of Mass coefficient K and basicity coefficient Mo

K＝54.19/38.58＝1.405>1.2；Mo＝38.37/49.71＝0.77

The table calculation shows that the mass coefficient reaches the standard, but the mixed slag is still acid slag. Proper slag excitant needs to be added in the preparation of the micro powder, so that the activity index of the micro powder is further improved.

National standard GB31893-2020 limit and determination method standard for water-soluble chromium in cement; the content of water-soluble chromium (VI chromium) in the cement is less than 10mg/kg (trivalent chromium can be converted into hexavalent chromium under the conditions of high temperature, high humidity and high PH value), and the concentration of the hexavalent chromium in the leachate is as follows: 0.601mg/L, sample hexavalent chromium mass percent: 0.000601% (0.601 mg hexavalent chromium co-leached in 100g sample) for the components of the mixture of the manganese-silicon slag and the low-carbon ferrochromium slag powder, the components meet the use specification of the cement industry.

4. The untreated silicomanganese slag, the pretreated silicomanganese slag and the pretreated low-carbon ferrochromium slag powder are mixed and ground in proportion to prepare micro powder for an activity experiment.

(1) Raw material

Cement of P.I.425

② ISO standard sand

Thirdly, manganese-silicon slag and low-carbon ferrochromium slag ash

Tetra (alkali activator, sulfate activator)

(2) Comparison of Activity

Activity comparison experiments were conducted according to the national standard of the people's republic of China GB/T18046-2008 "granulated blast furnace slag powder Standard for use in Cement and concrete" (Portland Cement: Fine powder: Standard Sand: Water 225:225:1350:225(1:1:6: 1))). The comparative data are shown in Table 6.

Table 6 table of comparative experimental data of activity

Through experimental calculation and activity experimental verification; the pretreated silicomanganese slag and the low-carbon ferrochromium slag ash are proportioned according to the proportion of 7:3, alkali and acid excitant with proper proportion are added for mixed grinding, and the grinding fineness D97 is less than or equal to 30 micrometers; the activity test indexes can meet the requirements of various indexes for producing S75 and S95 grade slag micro powder.

5. Analysis of blending experiments

Taking manganese-silicon slag and low-carbon ferrochrome slag ash in tables 1 and 2, pretreated manganese-silicon slag micro powder and low-carbon ferrochrome slag powder in tables 3 and 4, and the balance of ingredients comprising alkali activator silicate clinker and acid activator desulfurized gypsum, mixing and grinding the raw materials according to the proportion of (63%: 27%: 3%: 7%) to (59.5%: 25.5%: 5%: 10%), wherein the grinding fineness D97 is less than or equal to 30 microns. Blending experiments were performed according to the ratios in Table 7, and the results of performance testing are shown in Table 8.

TABLE 7 blending experiment sample preparation table

TABLE 8 results of activity test of cement and pure cement containing admixtures

The GB/T18046 technical indexes of the superfine slag powder are listed in Table 9.

TABLE 9GB/T18046 technical index

As can be seen from the data in Table 8, the pre-treated manganese-silicon slag and the pre-treated low-carbon ferrochrome slag ash are mixed into the mixed slag ash according to the proportion of 7: 3. The micro powder is prepared by mixing and grinding 90% of mixed slag ash, 3% of portland cement clinker, 7% of desulfurized gypsum or 85% of mixed slag ash, 5% of portland cement clinker and 10% of desulfurized gypsum. After the micro powder is mixed, the compression strength and the breaking strength of the cement micro powder reach the requirements of S95 level cement micro powder. From the aspect of environmental protection, the recycling of metallurgical wastes creates great value, simultaneously saves the use of cement clinker, and reduces the environmental pollution caused by cement production.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The process for producing the slag micropowder admixture by slag depletion is characterized by comprising the following steps

2. The process for producing the slag micropowder admixture by slag depletion according to claim 1, wherein in the S1. manganese-silicon slag treatment, the fineness of the grinding ore of the primary grinding is classified as: more than or equal to 80 meshes and 97 percent; not less than 120 meshes and 90 percent; not less than 200 meshes and 50 percent.

3. The process for producing slag micropowder admixture by slag depletion as claimed in claim 1, wherein in the S1. manganese slag treatment, the wind speed is adjusted to two levels of fineness of 200 meshes or less and 200 meshes or more during air classification, and 200 meshes or more is used as a preliminary material for producing slag micropowder.

4. The process for slag depletion production of superfine slag powder admixture according to claim 1, wherein in the S1. manganese-silica slag treatment, the magnetic separation strength is 5000-8000 GS.

5. The process for slag-depletion production of fine slag powder admixtures according to claim 1, wherein in the S1. manganese slag treatment, the micro-grinding grade is S95 grade, i.e. the specific surface area is 500m²More than g.

6. The process for producing the slag micropowder admixture by slag depletion according to claim 1, wherein in the S2. low-carbon ferrochrome slag ash treatment, the air speed of a separator is adjusted into two levels of fineness of less than 200 meshes and more than 200 meshes, and the fineness of more than 200 meshes is used as a ferrochrome slag preparation material.

7. The process for slag-depletion production of fine slag powder admixtures according to claim 1, wherein the acid-excitant is desulfurized gypsum.

8. The process for slag-depletion production of fine slag powder admixtures according to claim 1, wherein the alkali-activator is portland cement clinker.

9. Use of a slag-depleted slag micropowder admixture according to any one of claims 1 to 8 as a cement admixture.

10. The use of slag-depleted slag micropowder admixture according to claim 9 in an amount of from 20 to 50% by weight based on the cement.