CN113480206B

CN113480206B - Method for preparing cement mineralizer and producing cement clinker by using phosphate tailings

Info

Publication number: CN113480206B
Application number: CN202110890603.3A
Authority: CN
Inventors: 蒋家东; 范成; 康元兵; 刘凯军; 李川; 杨镇锋
Original assignee: Sichuan Shuangma Yibin Cement Manufacturing Co ltd
Current assignee: Sichuan Shuangma Yibin Cement Manufacturing Co ltd
Priority date: 2021-08-04
Filing date: 2021-08-04
Publication date: 2022-06-14
Anticipated expiration: 2041-08-04
Also published as: CN113480206A

Abstract

The invention discloses a method for preparing a cement mineralizer by using phosphate tailings and a method for producing cement clinker. The method for preparing the cement mineralizer by using the phosphate tailings comprises the following steps: mixing phosphorus tailings, in which P is present, with a first adjuvant comprising sulphuric acid and/or phosphoric acid₂O₅Is not less than 3%, SO₃The content of the carbonate in the phosphate tailings is not less than 1%, the phosphate tailings and a first auxiliary agent react to obtain a material A, the sum of the amounts of carbonate and bicarbonate in the material A is not more than the amount of carbonate in the phosphate tailings, and the material A is dried to obtain the phosphate tailings. The method can be used for preparing the cement mineralizer, so that the production cost of cement clinker can be reduced while the environmental pollution caused by stacking of phosphate tailings is reduced.

Description

Method for preparing cement mineralizer and producing cement clinker by using phosphate tailings

Technical Field

The invention belongs to the field of phosphorus tailings utilization, and particularly relates to a method for preparing a cement mineralizer and producing cement clinker by using phosphorus tailings.

Background

The phosphorus tailing waste slurry with too low grade in the production process of the phosphate ore dressing process has high moisture content, is slurry-shaped, is easy to block, has high treatment difficulty and low utilization rate, is mostly piled in a phosphorus tailing pond, has easy loss of chemical elements, reduces the use value on one hand, and also can cause pollution to the environment on the other hand. Therefore, a method for treating the phosphate tailings is needed, so that the phosphate tailings can be recycled and the environment can be protected.

Portland cement clinker mainly contains four major minerals: tricalcium silicate (i.e. 3 CaO. SiO)₂Often abbreviated as C₃S), dicalcium silicate (i.e., 2 CaO. SiO)₂Often abbreviated as C₂S), tricalcium aluminate (i.e. 3 CaO. Al)₂O₃Often abbreviated as C₃A) And tetracalcium aluminoferrite (i.e., 4 CaO. Al) solid solution₂O₃·Fe₂O₃). Wherein C₃S is the gelatinization in the clinkerThe best mineral, and the mineral with the highest forming temperature. Therefore, in order to save energy and improve cement quality, a method for reducing C is needed₃Formation temperature of S, increase of C₃Method of content of S.

Disclosure of Invention

Aiming at the problems, the invention provides a method for preparing a cement mineralizer by using phosphate tailings and a method for producing cement clinker by using the produced cement mineralizer.

The invention provides a method for preparing a cement mineralizer by using phosphate tailings, which comprises the following steps: mixing phosphorus tailings, in which P is present, with a first adjuvant comprising sulphuric acid and/or phosphoric acid₂O₅Is not less than 3%, SO₃The content of the carbonate in the phosphate tailings is not less than 1%, the phosphate tailings and a first auxiliary agent react to obtain a material A, the sum of the amounts of carbonate and bicarbonate in the material A is not more than the amount of carbonate in the phosphate tailings, and the material A is dried to obtain the phosphate tailings.

Compared with the prior art, the technical scheme has the following beneficial effects: CaF in phosphate tailings₂、P₂O₅The cement mineralizer can be prepared after the phosphorus tailings are treated by the technical scheme, so that the production cost of cement clinker can be reduced while the environmental pollution caused by stacking of the phosphorus tailings is reduced. The phosphorus tailings can be activated by mixing the phosphorus tailings with a first adjuvant, and in the process, sulfuric acid and phosphoric acid can react with fluorapatite, dolomite, calcium carbonate and the like in the phosphorus tailings, such as 4H₃PO₄+CaMg(CO₃)₂→CaMg(H₂PO₄)₄+2CO₂+2H₂O、CaCO₃+H₂SO4+H₂O→CaSO₄·2H₂O+CO₂And the like, can generate calcium magnesium phosphate, calcium sulfate and a small amount of active calcium, and on one hand, can avoid the calcium carbonate, magnesium carbonate, dolomite and the like in the phosphate tailings from being calcinedThe cement clinker is decomposed in the process of calcining the cement clinker, and a large amount of heat is absorbed, and on the other hand, a small amount of generated active calcium can play an inducing role, so that the decomposition heat of carbonate can be reduced in the process of calcining the cement clinker, and the decomposition of calcium carbonate is induced; and drying the material A to ensure that the material A loses water, becomes loose and is not sticky any more, and is convenient to be used as a mineralizer for producing cement clinker.

Preferably, the water content of the dried material A is less than 17%, and the method further comprises the step of mixing the material A with phosphorous slag after the material A is dried. The beneficial effect of this preferred scheme does: although the moisture of the dried material A is greatly reduced, the material A is still a fine powdery object, and the bonding force and the adsorption force among the powder in the blanking bin mainly influence the blanking speed; the main component of the phosphorus slag exists in a vitreous form, has a porous structure, takes amorphous granules as a main component (the content of granular vitreous bodies is about 90 percent), and mixes the dried material A with the phosphorus slag, the phosphorus slag destroys the adhesive force and the adsorption force among the powder, the material A in the powder form can be adsorbed and coated on the pore space of each phosphorus slag particle, the vitreous body in the phosphorus slag plays a role of a sphere nucleus to form a mixture particle ball (same as the snowball principle) which is similar to a round shape, a ball effect is formed during blanking, and the fluidity is greatly increased; tests show that 10 tons of materials are loaded in the bin, and under the same conditions, the blanking time of the cement mineralizer obtained by adopting the optimal technical scheme can be shortened from 180min to only 100min, namely, the blanking speed is improved by nearly one time after the material A is dried until the water content is lower than 17 percent and is mixed with phosphorous slag for treatment.

Preferably, the mass ratio of the dried material A to the phosphorus slag is (3-7) to (7-3). The beneficial effect of this preferred scheme does: the proportion of the two is controlled, so that on one hand, the obtained material has good fluidity and looseness; on the other hand, the activated calcium and the alkali in the material A can induce the decomposition of carbonate, the decomposition temperature of the carbonate is reduced, the calcium fluoride can destroy the silicon dioxide crystal lattice, the solid phase reaction is promoted, the stability of tricalcium silicate is enhanced, the vitreous body in the phosphorous slag plays a role of crystal nucleus in the solid phase reaction, the forming speed and the forming stability of the tricalcium silicate are promoted, the three effects interact and mutually promote, the mineralization of the mineralizer is maximized, and the two can well meet the requirement of being used as a cement mineralizer after being mixed according to the proportion.

Preferably, the first auxiliary agent is phosphogypsum, and the mass ratio of the phosphorus tailings to the phosphogypsum is (88-92) to (12-8). The beneficial effect of this preferred scheme does: phosphogypsum is a solid waste in wet-process phosphoric acid process, which contains Ca²⁺、Mg²⁺The metal ions also contain residual sulfuric acid and residual phosphoric acid, and the metal ions are used as a first auxiliary agent to react with the phosphorus tailings, so that the cost for treating the phosphorus tailings can be reduced, and the utilization rate of the phosphogypsum can be improved; controlling the mass ratio of the phosphate tailings and the phosphogypsum SO as to provide acid required by the reaction and avoid SO₃In excess.

Preferably, the pH of the phosphogypsum is < 3; and/or, in the phosphate tailings, by weight, P₂O₅3-8% of SO₃The content is 1-7%. The beneficial effect of this preferred scheme does: the pH value of the phosphogypsum is less than 3, so that enough acid required by the reaction can be provided; p₂O₅Mineralization is affected by too high or too low a content; SO (SO)₃Too high a content will affect emissions and too low a content will affect mineralization.

Preferably, drying said material a comprises: mixing the material A with a second adjuvant, wherein the second adjuvant comprises cement kiln dust and/or portland cement. The beneficial effect of this preferred scheme does: the water in the material A is removed at low cost, and the content of active calcium is increased. The cement kiln dust contains a large amount of active calcium and K₂SO₄、Na₂SO₄、2CaSO₄·K₂SO₄The solubility at 20 ℃ is 100-150 g/L, the dissolution rate is high, and the calcium carbonate reacts with the water of the material A quickly to separate out active calcium ions; the Portland cement reacts with the moisture in the material A quickly, on one hand, a large amount of water is consumed, on the other hand, a large amount of reaction heat is released, so that the temperature of a material pile is quickly raised by 30-40 ℃, and the evaporation of the moisture is accelerated.

Preferably, the mass ratio of the material A to the second auxiliary agent is (7-10) to 1; and/or stacking and curing the material A and a second auxiliary agent for 3-7 days after mixing. The beneficial effect of this preferred scheme does: the proportion of the material A and the second auxiliary agent is controlled, water in the material A is economically and quickly treated, the material A loses plasticity and viscosity, and the material A which cannot be blanked becomes blanked; preferably, the second auxiliary agent contains cement kiln dust and portland cement, the mass ratio of the material A to the cement kiln dust to the portland cement is 90: 5, the cost of the portland cement is high, and the value of the portland cement cannot be exerted after the ratio is exceeded; stacking and curing for 3-7 days, and providing necessary time for chemical reaction and water evaporation at lower cost.

The invention also provides a cement mineralizer, which is prepared from the phosphate tailings according to the preparation method. CaF in phosphorus tailings₂、P₂O₅High content of SO₃And the trace elements such as manganese, titanium and magnesium can reduce the temperature of liquid phase in the process of calcining cement clinker, increase the quantity of liquid phase, improve the easy burning property of raw materials, accelerate the solid phase reaction speed, shorten the clinker burning time, reduce the clinker burning temperature, save energy, effectively improve the machine hour output of a single kiln and improve the labor productivity. Specifically, in the high-temperature reaction process of producing cement clinker, fluorine, phosphorus and sulfur can be dissolved in the clinker minerals in a solid manner, so that the crystal lattices of the clinker minerals are deformed, the decomposition of carbonate is promoted, the liquid phase property is changed, and an intermediate transition phase 3C is generated₃S·CaF₂And 3C₂S·₃CaSO₄·CaF₂Can make C be₃S appears in advance, improves the hydration reaction activity of clinker minerals, reduces the liquid phase viscosity and reduces A ore (the A ore in the portland cement contains MgO and Al)₂O₃C of equal trace component₃S solid solution), the purpose of improving the clinker strength, overall improving the clinker quality, SO₃The trace elements of manganese, titanium and magnesium can reduce the temperature of liquid phase and increase the liquid phase quantity, so that the easy burning property of the raw material is obviously improved; after the treatment by the method, the phosphate tailings are activated, cured and granulated, the obtained cement mineralizer has high activity, dolomite which is difficult to decompose in the phosphate tailings is activated into active calcium, calcium sulfate and magnesium fluorophosphate, the mineralization is greatly improved,and the ball effect and the low-temperature eutectic characteristic of the glass body in the phosphorous slag and the crystal nucleus effect of the contained glass body are utilized, so that the method has obvious effects on clinker calcination and cement yield and quality improvement.

Preferably, the cement mineralizer comprises the following components in parts by weight: f-CaO: 10-20 parts; SiO 2₂: 10-40 parts; MgO: 4-20 parts of a solvent; p is₂O₅: 3-9 parts; CaF₂: 8-32 parts; SO (SO)₃: 1.5-8 parts.

The present invention also provides a method for producing cement clinker, comprising: adding the cement mineralizer into the raw materials, and sintering the raw materials to obtain cement clinker; wherein the mass ratio of the cement mineralizer to the raw meal is (2-5) to 100. The addition of the cement mineralizer to the raw meal may be either before or during sintering. Preferably, the sintering temperature is 1360 ℃ to 1420 ℃. Preferably, the raw meal contains at least CaO and SiO₂、Al₂O₃、Fe₂O₃A raw material of the source.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.

Example 1

The embodiment provides a method for preparing a cement mineralizer by using phosphate tailings, which comprises the following steps:

mixing phosphorus tailings, in which P is present, with a first adjuvant comprising sulphuric acid and/or phosphoric acid₂O₅In an amount of not less than 3%, SO₃The content of (A) is not less than 1%. In this embodiment, as a preferred scheme, the phosphate tailings are industrial waste residues, P, discharged in a raw material flotation process in a raw material link in a process of producing a phosphate fertilizer₂O₅3-8% of SO₃The content is 1-7%; the first auxiliary agent is phosphogypsum which is a solid waste in a wet-process phosphoric acid process, and the pH value is less than 3; the mass ratio of the phosphorus tailings to the phosphogypsum is (88-92) to (12-8).

And (2) reacting the phosphate tailings with the first auxiliary agent to obtain a material A, wherein the sum of the amount of carbonate and bicarbonate in the material A is not more than the amount of carbonate in the phosphate tailings, and drying the material A, specifically, when drying the material A, evaporating moisture by placing, removing moisture by drying, and adding other substances capable of reacting with water or accelerating the evaporation of the moisture. This embodiment preferably includes the step of drying the material a by mixing the material a with a second auxiliary agent, where the mixing of the material a with the second auxiliary agent may be performed before the drying of the material a, or during the drying of the material a, preferably, the material A is mixed with a second auxiliary agent before the material A is dried, then stacking and curing are carried out for 3-7 days, wherein the second auxiliary agent comprises cement kiln dust and/or portland cement, the mass ratio of the material A to the second auxiliary agent is (7-10) to 1, and the second auxiliary agent is preferably selected, the second auxiliary agent comprises cement kiln dust and portland cement, the cement kiln dust is cement kiln dust collection dust, the loss on ignition is less than 35 percent, the Portland cement is P.O42.5R cement meeting the GB175-2007 regulation, and the mass ratio of the material A, the cement kiln dust and the Portland cement is 90: 5.

In this embodiment, as an optimal solution, after drying, the water content of the material a is less than 17%, and after drying the material a, the method further includes mixing the material a with phosphorous slag, where the phosphorous slag is industrial waste slag generated in the extraction process of yellow phosphorus, and P is phosphorus₂O₅Content is more than 2.5%, CaF₂The content is more than 10%, and the mass ratio of the dried material A to the phosphorus slag is (3-7) to (7-3).

The present embodiment also provides a cement mineralizer, which is prepared according to the above method, and preferably, the cement mineralizer comprises the following components in parts by weight: f-CaO: 10-20 parts; SiO 2₂: 10-40 parts; MgO: 4-20 parts of a solvent; p₂O₅: 3-9 parts; CaF₂: 8-32 parts; SO (SO)₃: 1.5-8 parts.

The present embodiment also provides a method for producing cement clinker, comprising the steps of:providing a composition comprising at least CaO, SiO₂、Al₂O₃、Fe₂O₃The raw material of the source is prepared by adding the above-mentioned cement mineralizer to the raw material and sintering the raw material at 1360-1420 ℃ to obtain cement clinker. In this embodiment, as a preferable scheme, the raw material component for preparing the cement clinker comprises SiO in parts by weight₂: 13-14 parts; al (Al)₂O_3：3-4 parts of Fe₂O_3：1.8-2.2 parts of CaO: 43-44 parts; MgO: 1-2 parts; p₂O₅: 0.15-0.25 part; SO (SO)₃: 0.2 to 0.3 portion.

Example 2

according to the weight ratio of the phosphorus tailings to the phosphogypsum of 90: 10, the phosphorus tailings which are stockpiled or discharged from a flotation workshop are placed in a conveying device, the phosphogypsum is added into the phosphorus tailings by a metering and feeding device to be mixed, and the mixture is uniformly stirred. Wherein, in the phosphate tailings, P₂O₅Is 3-8% of SO₃The content of (A) is 1-7%; the phosphogypsum is a solid waste in a wet-process phosphoric acid process, and the pH value is less than 3.

And reacting the phosphate tailings with phosphogypsum to obtain a material A, wherein the sum of the amount of carbonate and bicarbonate in the material A is not more than the amount of carbonate in the phosphate tailings.

Adding the cement kiln dust and the portland cement into the material A by a metering and feeding device according to the weight ratio of the cement kiln dust to the portland cement to the material A of 5: 90, and covering, storing and curing for 72 hours according to a circular pile or a square pile to obtain a dried material A, wherein the water content of the dried material A is less than 17 percent. Wherein the cement kiln dust is cement kiln dust collection dust, and the loss on ignition is less than 35%; the portland cement is P.O42.5R cement which meets the regulation of GB 175-2007.

According to the weight ratio of the phosphorus slag to the dried material A being 3: 7, the phosphorus slag and the dried material A are added into a mixing device by a metering and feeding device, the phosphorus slag and the dried material A are fully mixed by a strong stirring and mixing device and are conveyed to a finished product warehouse, and the obtained product can be used as a cement mineralizer in the process of producing cement clinker, in particular to an active calcium-fluorine phosphorus composite mineralizer.

The embodiment also provides a method for producing cement clinker, wherein the active calcium-fluorine phosphorus composite mineralizer and raw materials containing limestone, sandstone, coal gangue and basalt are conveyed into a raw material mill through a proportioning belt according to the weight ratio of the cement mineralizer to the raw materials of (2-5) to 100, kiln tail waste gas is used as a drying heat source, a grinding roller is used for grinding and crushing the raw materials into fine powder on a grinding disc in the mill, hot air introduced into the mill is used for drying, the materials ground in the mill are taken up by rising hot airflow, after being sorted by a powder selecting machine at the upper part in the mill, the qualified raw material powder escapes from a vertical mill along with the hot airflow and enters a qualified raw material warehouse, the qualified raw materials enter a kiln belt metering scale and are metered in a cement kiln for calcination, and the active calcium-fluorine phosphorus composite mineralizer is combined with other components in the cement kiln at 1360-1420 ℃ to form cement mineral clinker.

The main chemical components (by weight) of the phosphate tailings used in this example include:

principal Components	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	P₂O₅	SO₃
								Fraction by weight/%)	2.98	0.65	0.42	27.19	18.25	5.87	4.57

The phosphorous slag used in this example comprises the following main chemical components (by weight):

principal Components	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	P₂O₅	SO₃
								Weight fractionFraction/%)	39.75	2.08	0.84	45.87	5.9	2.69	0.79

The main chemical components (by weight) in the phosphogypsum used in the embodiment are as follows:

the main chemical components (by weight) of the portland cement used in this example are:

principal Components	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	P₂O5	SO₃
								Fraction by weight/%)	16.81	4.77	5.41	59.49	2.22	0.27	2.81

The main chemical components (by weight) of the cement kiln dust used in the embodiment are as follows:

principal Components	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	K₂O	Na₂O	SO₃
									Fraction by weight/%)	11.54	3.79	2.04	43.80	1.61	1.09	0.17	1.13

The main chemical components (in parts by weight, LOSS on ignition) of the cement raw meal used in this example were:

chemical composition	LOSS	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO
							Fraction by weight/%)	36.39	12.81	2.92	1.90	44.43	1.35

The main chemical components and mineral composition (in parts by weight, LOSS on ignition) of the cement clinker obtained in this example were:

chemical composition	LOSS	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO
							Fraction by weight/%)	0.39	21.15	5.04	3.44	66.11	1.56

Mineral composition	C₃S	C₂S	C₃A	C₄AF	f-CaO
						Weight fraction/%	61.43	14.27	7.54	10.45	1.24

After the cement mineralizer of the embodiment is used, the yield of a vertical mill table is improved by at least 3%, the yield of a kiln table is increased by at least 1.2%, the cost of cement clinker is reduced by 1.8 yuan/ton, and the following table shows the physical properties of the cement clinker obtained after different proportions (weight fraction of the cement mineralizer in raw materials) of the cement mineralizer are mixed in the raw materials:

as is apparent from the table, the cement clinker produced by the method of this example has improved strength in use.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; all other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The method for preparing the cement mineralizer by using the phosphate tailings is characterized by comprising the following steps of:

mixing phosphorus tailings, in which P is present, with a first adjuvant comprising sulphuric acid and/or phosphoric acid₂O₅Is not less than 3%, SO₃The content of the first auxiliary agent is not less than 1 percent, the first auxiliary agent is phosphogypsum, and the mass ratio of the phosphate tailings to the phosphogypsum is (88-92) to (12-8);

reacting the phosphate tailings with the first auxiliary agent to obtain a material A, wherein the sum of the amount of carbonate and bicarbonate in the material A is not more than the amount of carbonate in the phosphate tailings, and drying the material A;

and the water content of the dried material A is less than 17%, and the step of mixing the material A with phosphorous slag is further included after the material A is dried.

2. The method according to claim 1, wherein the mass ratio of the dried material A to the phosphorus slag is (3-7) to (7-3).

3. A process according to claim 1, characterised in that the pH of the phosphogypsum is < 3;

and/or, in the phosphate tailings, P₂O₅3-8% of SO₃The content is 1-7%.

4. The method of claim 1, wherein drying the material a comprises: mixing the material A with a second adjuvant, wherein the second adjuvant comprises cement kiln dust and/or portland cement.

5. The method according to claim 4, characterized in that the mass ratio of the material A to the second auxiliary agent is (7-10): 1;

and/or stacking and curing the material A and a second auxiliary agent for 3-7 days after mixing.

6. A cement mineralising agent, characterised in that it is prepared according to the method of any one of claims 1 to 5.

7. A cement mineralizer according to claim 6, characterized by comprising the following components, in parts by weight:

f-CaO: 10-20 parts;

SiO₂: 10-40 parts;

MgO: 4-20 parts;

P₂O₅: 3-9 parts;

CaF₂: 8-32 parts;

SO₃: 1.5-8 parts.

8. A method of producing cement clinker, comprising: adding a cement mineralizer according to claim 6 or 7 to raw meal, and sintering the raw meal to obtain cement clinker; wherein the mass ratio of the cement mineralizer to the raw meal is (2-5) to 100.

9. The method of claim 8, wherein the sintering temperature is 1360 ℃ to 1420 ℃.