CN112279532B

CN112279532B - Mineral admixture and preparation method thereof

Info

Publication number: CN112279532B
Application number: CN202011112957.7A
Authority: CN
Inventors: 王肇嘉; 刘艳军; 徐瑞来; 李沙; 李润丰
Original assignee: Beijing Building Materials Academy of Sciences Research
Current assignee: Beijing Building Materials Academy of Sciences Research
Priority date: 2020-10-16
Filing date: 2020-10-16
Publication date: 2022-01-28
Anticipated expiration: 2040-10-16
Also published as: CN112279532A

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a mineral admixture and a preparation method thereof. The mineral admixture has a crystalline phase proportion of 60 mass% or more; the crystalline phase comprises, based on the total mass of the crystalline phase: 0-10% of dicalcium silicate crystal, 0-3% of calcium oxide crystal, 50-85% of iron oxide-doped calcium sulfosilicate crystal, 0-12% of calcium sulfoaluminate crystal and 0-15% of tetracalcium aluminoferrite crystal. The mineral admixture has high hydration activity, and after 30% of reference cement is replaced by the mineral admixture, according to GBT 1596-. Meanwhile, the fertilizer can be prepared by using industrial solid wastes as raw materials, so that waste is changed into valuable.

Description

Mineral admixture and preparation method thereof

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to a mineral admixture and a preparation method thereof.

Background

Approximately 0.9 tons of carbon dioxide (CO) are released for producing one ton of cement clinker₂). In recent years, with the increasing worldwide demand for cement and the growing availability of raw material resources, energy resources and CO₂Emission certificates and air entraining production cost are continuously increased, and cement enterprises reduce the clinker rate by adding limestone powder, fly ash, granulated slag and the like as clinker substitute materials. The development of a large volume of industrial solid waste for replacing cementitious materials is becoming a focus of increasing attention.

The method generates a large amount of industrial solid waste in the industrial fields of thermal treatment of solid waste, coal power generation, renewable energy, metallurgy, mineral separation and the like. Depending on the quality, composition and application field of the bulk industrial solid wastes, the bulk industrial solid wastes can be partially or completely used as substitute raw materials of various processes and products, such as silicon, aluminum, iron and calcium raw materials for producing portland cement clinker, concrete admixture, asphalt and concrete aggregate, and the like.

However, the direct use of industrial solid wastes is problematic due to various disadvantages (e.g., physical or chemical level unevenness, harmful components such as organic matters or heavy metals) inherent to the bulk industrial solid wastes. In particular, a decrease in the hydration activity and a deterioration in the volume stability of portland cement clinker can lead to serious engineering quality problems. Large volumes of industrial solid waste can also encounter difficulties in long-term storage, and the leaching process of organic or heavy metals can pollute the atmosphere, soil and water resources in surrounding areas. Therefore, the disposal of bulk industrial solid wastes forms a major challenge to the living environment, and at present, no large-scale and clean solution is available, and the research and development of the technology for resource utilization of bulk solid wastes as high as possible and sustainable has important significance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the mineral admixture with high hydration activity, low calcination temperature and high industrial solid waste utilization rate.

Specifically, the invention provides the following technical scheme:

a mineral admixture in which the proportion of the crystalline phase is 60 mass% or more;

the crystalline phase comprises, based on the total mass of the crystalline phase:

preferably, in the mineral admixture, the proportion of the crystal phase is 70 mass% or more;

preferably, in the above mineral admixture, in the iron oxide-doped calcium sulfosilicate crystal, the molar ratio of Ga, Si, Fe and S is 5: 2 x: (2-2 x): 1, wherein x is more than or equal to 0.9 and less than or equal to 1, preferably more than or equal to 0.94 and less than or equal to 0.98.

Preferably, the mineral admixture is prepared from the following raw materials in parts by mass: 15-35 parts of a silicon-aluminum material, 15-30 parts of gypsum, 45-79 parts of a calcium material and 0-5 parts of a mineralizer.

Preferably, in the above mineral admixture, SiO is contained in the silica-alumina material₂And Al₂O₃The total content of (A) is more than 80 mass percent, Na₂O and K₂The total content of O is 5 mass% or less;

and/or the calcium material has a calcium oxide content of 38 mass% or more.

Preferably, in the mineral admixture, the silica-alumina material is selected from one or more of low-grade bauxite, molybdenum tailings, iron tailings, gold tailings and coal gangue;

and/or the gypsum is selected from one or more than two of natural dihydrate gypsum, natural anhydrite, desulfurized gypsum, fluorgypsum, phosphogypsum and desulfurized fly ash;

and/or the calcareous material is selected from one or more than two of low-grade natural limestone, papermaking white mud, waste marble stone powder, stainless steel slag and carbide slag;

fe in the raw material of the mineral admixture₂O₃The content of (b) is 10% by mass or less, preferably 5 to 10% by mass.

Preferably, in the above mineral admixture, the mineralizer is industrial waste containing one or more of zinc, fluorine, copper, nickel and manganese, and preferably, the mineralizer contains zinc oxide, copper oxide, nickel oxide, manganese oxide and CaF based on the total mass of the raw materials for preparing the mineral admixture₂The total content of (B) is 2 mass% or moreThe following steps.

According to the invention, the catalyst comprises C2S, CaO,

The high hydration activity mineral admixture with C4A3S and C4AF as main crystal phase components or the high hydration activity mineral admixture obtained by grinding the admixture by adding other mineral admixtures comprises the following components:

0 to 10%, preferably 2 to 8%, still more preferably 3 to 5% by weight of C2S;

CaO in an amount of 0 to 3.0% by weight, preferably 0.5 to 2% by weight, and still more preferably 1 to 1.5% by weight;

·

50 to 85%, preferably 60 to 85%, still more preferably 70 to 85% by weight;

·

0 to 12%, preferably 5 to 12%, still more preferably 10 to 12% by weight;

c4AF is from 0 to 15%, preferably from 5 to 15%, even more preferably from 10 to 15% by weight.

Preferably, in the above mineral admixture, the oxides comprise, based on the total mass of the oxides:

CaO is 35-60%, preferably 40-55%, and more preferably 45-50%;

SiO₂5 to 25%, preferably 10 to 20%, more preferably 15 to 18%;

Al₂O₃5 to 30%, preferably 10 to 20%, more preferably 12 to 18%;

SO₃3 to 20%, preferably 8 to 20%, more preferably 10 to 20%;

Fe₂O₃3 to 10%, preferably 5 to 10%, more preferably 7 to 10%.

Preferably, in the above mineral admixture, Al is calculated on the basis of the total mass of oxides₂O₃With Fe₂O₃The total content of (A) is 15-30%, preferably18 to 26%, more preferably 20 to 24%.

Preferably, in the mineral admixture, in the amorphous phase, the main chemical elements and the proportions (expressed as oxides) of the main chemical elements are CaO (25-40%), Al2O3 (12-20%), SiO2 (10-20%), Fe2O3 (1-8%), SO3 (1-5%), MgO (1-10%), Na2O (0.5-2.5%) and K2O (0.5-2.5%), and the total amount is 100%, and the content is less than or equal to 40% of the total weight of the material.

The invention also provides a preparation method of the mineral admixture, which comprises the following steps:

(1) adding the silicon-aluminum material, the gypsum, the calcareous material and the mineralizer into a ball mill for grinding to obtain a raw material;

(2) and calcining the raw material at 1150-1230 ℃ for a certain time.

Preferably, in the preparation method, in the step (1), the silico-aluminous material, the gypsum, the calcareous material and the mineralizer are added into a ball mill and ground until the balance of a sieve with the size of 0.090mm is less than 12%, so as to obtain the raw material;

and/or, in the step (2), calcining the raw material at 1150-1230 ℃ for 15-60 min;

and/or, in the step (2), after the calcination, taking out the high-temperature material and quenching the high-temperature material to room temperature, preferably quenching the high-temperature material to room temperature at a speed of more than 150 ℃/min.

Preferably, in the above preparation method, before the calcining in step (2), a step of pressing the raw material into a test cake is further included.

Preferably, in the preparation method, in the step (2), after the calcination, the material cooled to room temperature is crushed by a jaw crusher until the particle size is less than 5mm, then a proper amount of fly ash or thermal power plant vulcanization bed furnace bottom slag is added, and the mixture is ground for 20-40 min by a ball mill until the sieve residue of 0.045mm is less than 1%.

Preferably, in the preparation method, the calcination temperature is 1150-1170 ℃; the content of calcium sulfosilicate crystal form existing in the form of inorganic crystal structure database number ICSD4332 is more than 60 mass percent, and the content of calcium sulfosilicate crystal form existing in the form of inorganic crystal structure database number ICSD85123 is less than 15 mass percent based on the total mass of calcium sulfosilicate crystal;

and/or the calcination temperature is 1170-1190 ℃, and the content of calcium sulfosilicate crystal form existing in the form of the inorganic crystal structure database number ICSD4332 is below 50 mass percent and the content of calcium sulfosilicate crystal form existing in the form of the inorganic crystal structure database number ICSD85123 is above 30 mass percent based on the total mass of the calcium sulfosilicate crystal;

and/or the calcination temperature is 1190-1230 ℃; the content of calcium sulfosilicate crystal form existing in the form of inorganic crystal structure database number ICSD4332 is more than 70 mass%, and the content of calcium sulfosilicate crystal form existing in the form of inorganic crystal structure database number ICSD85123 is less than 15 mass%, based on the total mass of calcium sulfosilicate crystal.

The invention has the following beneficial effects:

according to the invention, the mineral admixture which takes hydrated high-activity calcium sulfosilicate crystals and amorphous substances as main components is produced by treating bulk industrial solid wastes at low temperature, so that the Portland cement clinker can be replaced at a high proportion, the energy consumption and carbon emission in the cement production process are reduced, and the large-scale industrial solid wastes and high added value utilization are realized;

the mineral admixture has high hydration activity, and after 30% of reference cement is replaced by the mineral admixture, according to GBT 1596-. Meanwhile, the fertilizer can be prepared by using industrial solid wastes as raw materials, so that waste is changed into valuable.

Drawings

FIG. 1 shows the variation of the crystalline form of calcium sulfosilicate crystals in mineral admixtures prepared in example 1 at different calcination temperatures.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the scope of the present invention is not limited thereto.

The experimental procedures used in the following examples are conventional unless otherwise specified. The experimental raw materials and the related equipments used in the following examples are commercially available unless otherwise specified.

The proportion of crystal phases and the content of each crystal phase in the crystal phases in the following examples were quantitatively determined by X-ray diffraction analysis and Rieltveld Refinement calculation program.

Example 1

Mixing low-grade limestone, desulfurized gypsum, molybdenum tailings and chemical solid waste mineralizer containing calcium fluoride according to the proportion of 58 percent to 19.0 percent to 22.0 percent to 1.0 percent, and grinding the mixture by using a ball mill until the particles larger than 90 microns in the mixture are less than 1 percent; then, adding a small amount of water into the mixture, uniformly stirring, and pressing into a test cake with the thickness of about 2cm and the diameter of 5cm by using a press machine; and then, putting the test cake into a high-temperature electric furnace for calcination, wherein the heating rate of the electric furnace is 15 ℃/min, calcining for 30min at 1180 ℃, and then rapidly cooling to room temperature to obtain the test cake. Wherein SiO in the molybdenum tailings₂、Al₂O₃、Na₂O、K₂O and Fe₂O₃The contents of the components are 65.93%, 13.31%, 2.51%, 2.47% and 3.58% respectively; the content of calcium oxide in the low-grade limestone is 46.3 percent; CaF in the chemical solid waste mineralizer containing calcium fluoride₂The content was 17.2%.

The mineral admixture with high hydration activity prepared in this example without the mineral admixture contained 81.7% crystalline phase and 18.3% amorphous phase. The content of dicalcium silicate (C2S) in the crystalline phase was 8.3%; the content of calcium oxide (CaO) is 0.4 percent; iron oxide doped stable calcium sulfosilicate

Content (78.9%), x is 0.94; calcium sulphoaluminate

Content (7.2%); tetracalcium aluminoferrite (C4AF) content (5.2%).

After 30% of reference cement is replaced by the prepared high hydration active mineral admixture, the 3d activity index is 116%, the 7d activity index is 138% and the 28d activity index is 135% according to GBT 1596-.

Example 2

Mixing paper-making white mud, desulfurized gypsum, gold tailings and manganese slag industrial solid waste mineralizer containing manganese oxide according to the proportion of 65 percent to 15.0 percent to 18.0 percent to 2.0 percent, and grinding the mixture by using a ball mill until the particle size of more than 90 micrometers in the mixture is less than 1 percent; then, adding a small amount of water into the mixture, uniformly stirring, and pressing into a test cake with the thickness of about 2cm and the diameter of 5cm by using a press machine; and then, putting the test cake into a high-temperature electric furnace for calcination, wherein the heating rate of the electric furnace is 15 ℃/min, the calcination is carried out for 20min at 1230 ℃, and then the test cake is rapidly cooled to the room temperature, thus obtaining the material. Wherein SiO in the gold tailings₂、Al₂O₃、Na₂O、K₂O and Fe₂O₃The contents of the components are respectively 64.6%, 10.8%, 1.98%, 3.01% and 7.6%; the content of calcium oxide in the papermaking white mud is 51.0 percent; the manganese slag industrial solid waste mineralizer containing manganese oxide contains 6.19% of manganese oxide.

The mineral admixture with high hydration activity prepared in this example without the mineral admixture contained 92.1% crystalline phase and 7.9% amorphous phase. The content of dicalcium silicate (C2S) in the crystalline phase was 3.2%; the content of calcium oxide (CaO) is 0.7 percent; iron oxide doped stable calcium sulfosilicate

Content (76.9%), x is 0.96; calcium sulphoaluminate

Content (6.8%); content of tetracalcium aluminoferrite (C4AF) (12.4%).

After 30% of reference cement is replaced by the prepared high hydration active mineral admixture, the 3d activity index is 119%, the 7d activity index is 136% and the 28d activity index is 138% according to the GBT 1596-.

Example 3

Mixing carbide slag, phosphogypsum, coal gangue and copper slag industrial solid waste mineralizer containing copper oxide according to the proportion of 48 percent to 21.0 percent to 30.0 percent to 1.0 percent, and grinding the mixture by a ball mill until the particles larger than 90 microns in the mixture are smaller than the particles smaller than 90 microns1 percent; then, adding a small amount of water into the mixture, uniformly stirring, and pressing into a test cake with the thickness of about 2cm and the diameter of 5cm by using a press machine; and then, putting the test cake into a high-temperature electric furnace for calcination, wherein the heating rate of the electric furnace is 15 ℃/min, calcining for 30min at 1150 ℃, and then rapidly cooling to room temperature to obtain the test cake. Wherein SiO in the coal gangue₂、Al₂O₃、Na₂O、K₂O and Fe₂O₃The contents of the components are 58.97%, 23.55%, 0.48%, 1.32% and 2.71% respectively; the content of calcium oxide in the carbide slag is 68.1%; the copper slag industrial solid waste mineralizer containing copper oxide contains 0.52% of copper oxide.

The mineral admixture with high hydration activity prepared in this example without the mineral admixture contained 73.2% crystalline phase and 26.8% amorphous phase. The content of dicalcium silicate (C2S) in the crystal phase was 9.8%; the content of calcium oxide (CaO) is 2.1 percent; iron oxide doped stable calcium sulfosilicate

Content (61.7%), x is 0.98; calcium sulphoaluminate

Content (11.9%); tetracalcium aluminoferrite (C4AF) content (14.5%).

After 30% of reference cement is replaced by the prepared high hydration active mineral admixture, the activity index of 121% at 3d, the activity index of 135% at 7d and the activity index of 130% at 28d are tested according to GBT 1596-.

Example 4

Waste marble powder, fluorgypsum, iron tailings and zinc oxide-containing lead-zinc tailings industrial solid waste mineralizer are mixed according to the proportion of 45 percent to 25.0 percent to 28.0 percent to 2.0 percent, and the mixture is ground by a ball mill until the particle size of more than 90 microns in the mixture is less than 1 percent; then, adding a small amount of water into the mixture, uniformly stirring, and pressing into a test cake with the thickness of about 2cm and the diameter of 5cm by using a press machine; and then, putting the test cake into a high-temperature electric furnace for calcining, wherein the heating rate of the electric furnace is 15 ℃/min, calcining for 40min at 1200 ℃, and then rapidly cooling to room temperature to obtain the test cake. Wherein SiO in the iron tailings₂、Al₂O₃、Na₂O、K₂O and Fe₂O₃The contents of the components are respectively 72.4%, 7.84%, 1.63%, 2.21% and 7.80%; the content of calcium oxide in the waste marble powder is 50.3 percent; the zinc oxide-containing lead-zinc tailing industrial solid waste mineralizer contains 0.85% of zinc oxide.

The mineral admixture with high hydration activity prepared in this example without the mineral admixture contained 87.4% crystalline phase and 12.6% amorphous phase. The content of dicalcium silicate (C2S) in the crystalline phase was 3.4%; the content of calcium oxide (CaO) is 1.2 percent; iron oxide doped stable calcium sulfosilicate

Content (84.1%), x is 0.97; calcium sulphoaluminate

Content (6.3%); content of tetracalcium aluminoferrite (C4AF) (5.0%).

After 30% of reference cement is replaced by the prepared high-hydration active mineral admixture, the activity index of 3d is 123%, the activity index of 7d is 137% and the activity index of 28d is 132% according to the test of GBT 1596-2005.

Comparative example 1

Comparative example 1 differs from example 1 only in that: the calcination temperature of the high-temperature electric furnace is 1100 ℃.

The mineral blend prepared in comparative example 1 had a crystalline phase of 95.6% and an amorphous phase of 4.4%. The content of dicalcium silicate (C2S) in the crystalline phase was 44.3%; the content of calcium oxide (CaO) is 12.3 percent; iron oxide doped stable calcium sulfosilicate

Content (18.9%), x is 0.94; calcium sulphoaluminate

Content (7.2%); tetracalcium aluminoferrite (C4AF) content (1.2%), calcium sulfate content 13.2%, quartz content 2.9%.

After 30% of the reference cement is replaced by the mineral admixture prepared in the comparative example 1, the cement mortar test block has poor stability and cracks according to the detection of GBT 1596-2005. Namely, the mineral admixture prepared by the method does not meet the standard requirement and can not be used as a cement concrete admixture.

Comparative example 2

Comparative example 2 differs from example 1 only in that: the calcination temperature of the high-temperature electric furnace is 1300 ℃.

The mineral blend prepared in comparative example 2 had a crystalline phase of 71.9% and an amorphous phase of 28.1%. The content of dicalcium silicate (C2S) in the crystalline phase was 47.1%; the content of calcium oxide (CaO) is 3.3%; iron oxide doped stable calcium sulfosilicate

Content (5.6%), x is 0.95; calcium sulphoaluminate

Content (8.2%); the content of tetracalcium aluminoferrite (C4AF) (11.0%), the content of calcium sulfate (10.4%), the content of tricalcium aluminate (9.3%) and the content of dodecacalcium heptaluminate (5.1%).

After 30% of the reference cement is replaced by the mineral admixture prepared in the comparative example 2, the 3d activity index is 85%, the 7d activity index is 103% and the 28d activity index is 105% according to the GBT1596-2005 detection.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A mineral admixture characterized in that the proportion of a crystalline phase in the mineral admixture is 70 mass% or more;

5-10% of dicalcium silicate crystals;

1-3% of calcium oxide crystals;

60-85% of iron oxide doped calcium sulfosilicate crystal;

5-12% of calcium sulphoaluminate crystals;

10-15% of tetracalcium aluminoferrite crystal

In the iron oxide-doped calcium sulfosilicate crystal, the molar ratio of Ca, Si, Fe and S is 5: 2 x: (2-2 x): 1, wherein x is more than or equal to 0.9 and less than or equal to 1;

the mineral admixture is prepared from the following raw materials in parts by mass: 15-35 parts of a silicon-aluminum material, 15-30 parts of gypsum, 45-79 parts of a calcium material and 0-5 parts of a mineralizer;

the preparation method of the mineral admixture comprises the following steps:

(2) calcining the raw material at 1150-1230 ℃ for a certain time;

in the step (1), adding the silicon-aluminum material, the gypsum, the calcium material and the mineralizer into a ball mill for grinding until the balance of a sieve with the size of 0.090mm is less than 12%, so as to obtain the raw material;

in the step (2), calcining the raw material at 1150-1230 ℃ for 15-60 min;

in the step (2), after the calcination, the high-temperature material is taken out and quenched to room temperature at a speed of more than 150 ℃/min.

2. The mineral admixture of claim 1, wherein 0.94 x 0.98.

3. Mineral admixture according to claim 1, wherein in the alumino-silica material, SiO is present₂And Al₂O₃Has a total content of at least 70 mass% of Na₂O and K₂The total content of O is 5 mass% or less;

and/or the calcium material has a calcium oxide content of 38 mass% or more.

4. The mineral admixture according to claim 1 or 3, wherein said alumino-silica material is selected from one or more of low grade bauxite, molybdenum tailings, iron tailings, gold tailings, coal gangue;

and/or Fe in the raw material of the mineral admixture₂O₃The content of (B) is 10 mass% or less.

5. A mineral admixture according to claim 1 or 3, wherein said mineralising agent is an industrial waste containing one or more of zinc, fluorine, copper, nickel, manganese.

6. The mineral admixture according to claim 5, wherein the mineralizer comprises zinc oxide, copper oxide, nickel oxide, manganese oxide and CaF, based on the total mass of the raw materials used to prepare the mineral admixture₂The total content of (B) is 2 mass% or less.

7. A process for the preparation of a mineral admixture according to any one of claims 1 to 6 comprising the steps of:

(2) calcining the raw material at 1150-1230 ℃ for a certain time;

and/or in the step (2), after the calcination, taking out the high-temperature material, and rapidly cooling to room temperature at a speed of more than 150 ℃/min.

8. The method for preparing a mineral admixture according to claim 7, wherein the calcination temperature is 1150 to 1170 ℃; the content of calcium sulfosilicate crystal form existing in the form of inorganic crystal structure database number ICSD4332 is more than 60 mass percent, and the content of calcium sulfosilicate crystal form existing in the form of inorganic crystal structure database number ICSD85123 is less than 15 mass percent based on the total mass of calcium sulfosilicate crystal;