阅读说明：本技术 一种磷石膏-二灰系复合胶凝材料及制备方法 (Phosphogypsum-lime series composite cementing material and preparation method thereof ) 是由 宁朝阳 王亮 赵长龙 曲天杰 刘勇 孔德文 谢浪 于 2021-07-22 设计创作，主要内容包括：本发明公开了一种磷石膏-二灰系复合胶凝材料及制备方法。按重量份计,是以下述原料制得：磷石膏：44～56份、水泥：4～16份、生石灰：8～16份、粉煤灰：24～32份、固化剂：0.8～1.6份。本发明具有工艺简单、提高磷石膏和粉煤灰综合利用率、抗压及耐水性能优良、具有适宜的凝结时间和微膨胀性等特点。(The invention discloses a phosphogypsum-lime composite cementing material and a preparation method thereof. The composition is prepared from the following raw materials in parts by weight: phosphogypsum: 44-56 parts of cement: 4-16 parts of quicklime: 8-16 parts of fly ash: 24-32 parts of curing agent: 0.8 to 1.6 portions. The invention has the characteristics of simple process, improved comprehensive utilization rate of the phosphogypsum and the fly ash, excellent compression resistance and water resistance, proper setting time, micro-expansibility and the like.)

1. The phosphogypsum-fly ash series composite cementing material is characterized by being prepared from the following raw materials in parts by weight:

2. the phosphogypsum-fly ash composite cementing material according to claim 1, which is characterized by being prepared from the following raw materials in parts by weight:

3. the phosphogypsum-fly ash composite cementitious material according to claim 1 or 2, characterized in that the phosphogypsum is: crushing, drying at 60 ℃ to remove part of free water, and sieving by a 0.315mm square-hole sieve to obtain the phosphogypsum.

4. The phosphogypsum-fly ash composite cementitious material according to claim 1 or 2, characterized in that the fly ash is: first-grade fly ash, 12% of 45 μm screen residue.

5. The phosphogypsum-fly ash composite cementing material according to the claim 1 or 2, which is characterized in that the curing agent is a liquid curing agent and is an organic compound taking an elastic styrene-acrylic emulsion as a main component.

6. The phosphogypsum-fly ash composite cementitious material according to claim 1 or 2, characterised in that it is applied to road base.

7. The preparation method of the phosphogypsum-fly ash composite cementing material according to the claim 1 or 2, which is characterized by comprising the following steps:

a. uniformly mixing phosphogypsum, cement, quicklime and fly ash to obtain a mixed dry material;

b. respectively doping water with the ratio of a curing agent to water to gel being 0.32-0.35 into the dry mixed materials, firstly stirring for 40-70 s at the rotating speed of 60-125 r/min, and then stirring for 60-90 s at the rotating speed of 125-285 r/min to prepare composite slurry; the water-glue ratio is the weight ratio of water to the dry mixed material;

c. and (3) filling the composite slurry into a mold, and maintaining the composite slurry to a corresponding age to obtain the composite slurry.

8. The preparation method of the phosphogypsum-fly ash composite cementing material according to claim 7, which is characterized in that the step c specifically comprises the following steps: filling the composite slurry into a mold, inserting and tamping, and flattening the surface; and (3) after demolding, placing the mixture in a standard constant humidity curing box for curing the mixed mortar test piece to a corresponding age under natural conditions or under the conditions that the temperature is 20 +/-2 ℃ and the relative humidity is 50 +/-3 percent, and obtaining the mortar.

Technical Field

The invention relates to the technical field of comprehensive utilization of phosphogypsum and fly ash, in particular to a phosphogypsum-fly ash composite cementing material and a preparation method thereof.

Background

With the continuous development of industrialization in China, a large amount of solid wastes (solid wastes for short) such as waste residues and dust are generated in the industrial production process, the yield reaches 33 hundred million t only in 2017, but the comprehensive utilization rate is only 62%, and most of the solid wastes are not effectively utilized and are stockpiled and disposed. The large-volume stacking of solid wastes not only occupies a large amount of land and increases the enterprise cost, but also seriously pollutes the ecological environment and harms the human health, and even causes various systematic potential safety hazards. Therefore, how to effectively utilize industrial solid wastes and realize reduction, harmlessness and reclamation of the industrial solid wastes becomes a key problem to be solved urgently at present. Wherein, the phosphogypsum and the fly ash are two solid wastes with large output in China, which are respectively approximate to 8000 kilo tons and 1 hundred million tons, but the utilization rate is lower than that of the phosphogypsum and the fly ash which are respectively 40 percent and 45 percent on average. Therefore, how to improve the comprehensive utilization rate becomes the key point of the current solid waste utilization research.

Disclosure of Invention

The invention aims to provide a phosphogypsum-fly ash series composite cementing material and a preparation method thereof. The invention has the characteristics of simple process, improved comprehensive utilization rate of the phosphogypsum and the fly ash, excellent compression resistance and water resistance, proper setting time, micro-expansibility and the like.

The technical scheme of the invention is as follows: the phosphogypsum-fly ash series composite cementing material is prepared from the following raw materials in parts by weight:

phosphogypsum: 44-56 parts of cement: 4 to 16 portions of,

Quick lime: 8-16 parts of fly ash: 24 to 32 parts of,

Curing agent: 0.8 to 1.6 portions.

The phosphogypsum-fly ash series composite cementing material is prepared from the following raw materials in parts by weight:

phosphogypsum: 47-53 parts of cement: 7 to 13 parts of,

Quick lime: 10-14 parts of fly ash: 26 to 30 parts of,

Curing agent: 1 to 1.4 portions.

In the phosphogypsum-fly ash composite cementing material, the phosphogypsum is as follows: crushing, drying at 60 ℃ to remove part of free water, and sieving by a 0.315mm square-hole sieve to obtain the phosphogypsum.

In the phosphogypsum-fly ash composite cementing material, the phosphogypsum is as follows: the fly ash comprises the following components: first-grade fly ash, 12% of 45 μm screen residue.

In the phosphogypsum-fly ash composite cementing material, the phosphogypsum is as follows: the curing agent is a liquid curing agent and is an organic compound mainly composed of elastic styrene-acrylic emulsion.

In the phosphogypsum-fly ash composite cementing material, the phosphogypsum is as follows: the composite cementing material is applied to a road base.

The preparation method of the phosphogypsum-lime composite cementing material comprises the following steps:

a. uniformly mixing phosphogypsum, cement, quicklime and fly ash to obtain a mixed dry material;

b. respectively doping water with the ratio of a curing agent to water to gel being 0.32-0.35 into the dry mixed materials, firstly stirring for 40-70 s at the rotating speed of 60-125 r/min, and then stirring for 60-90 s at the rotating speed of 125-285 r/min to prepare composite slurry; the water-glue ratio is the weight ratio of water to the dry mixed material;

c. and (3) filling the composite slurry into a mold, and maintaining the composite slurry to a corresponding age to obtain the composite slurry.

In the preparation method of the phosphogypsum-lime composite cementing material, the step c is specifically as follows: filling the composite slurry into a mold, inserting and tamping, and flattening the surface; and (3) after demolding, placing the mixture in a standard constant humidity curing box for curing the mixed mortar test piece to a corresponding age under natural conditions or under the conditions that the temperature is 20 +/-2 ℃ and the relative humidity is 50 +/-3 percent, and obtaining the mortar.

Has the advantages that: compared with the prior art, the phosphogypsum and cement are added to be used together with the lime-fly ash base material, so that the defects of low strength and large brittleness of original phosphogypsum are effectively overcome, and the defects of low early strength, poor water stability and easy serious shortening of the service life of the lime-fly ash base material due to short condensation time and more shrinkage reflection cracks of the lime-fly ash base material are overcome; meanwhile, the phosphogypsum is doped into the lime-based base material, so that the characteristics of high absolute strength and good integrity of the lime-based base material are fully exerted, a plurality of performances of the composite cementing material are improved, and finally, the lime-based base cementing material which is high in strength and has suitable setting time and micro-expansibility is developed, and the method has important significance for ensuring long-term service of the pavement.

When the composite cementing material is prepared, the ratio of the phosphogypsum to the fly ash in the raw materials is extremely large, the comprehensive utilization rate of industrial solid waste is effectively improved, the energy consumption is reduced, and the environmental pollution is reduced.

Specifically, compared with the prior art, the invention has the following beneficial effects:

(1) the invention effectively regulates and controls the performance of the two-ash-based composite cementing material by adding the phosphogypsum and the cement into the quick lime and the fly ash. The semi-rigid material of lime fly ash has higher strength, rigidity, plate property and pavement bearing capacity, the phosphogypsum can effectively adjust the setting time and the expansion performance, improve the cracking damage of the base material, and can adjust the mechanical property and the water resistance of the composite material by combining with the cement, thereby obtaining the low-cost phosphogypsum-lime composite cementing material which meets the requirement of engineering application performance.

(2) The invention effectively increases the comprehensive utilization rate of the phosphogypsum. The undisturbed phosphogypsum is not beneficial to being directly applied to the engineering field due to the reasons of low strength, large brittleness and the like; when the phosphogypsum is generally applied in the engineering field, the phosphogypsum is calcined into the hemihydrate phosphogypsum at high temperature, and the energy consumption is high. In order to solve the technical problem, the invention adds the original phosphogypsum into lime and fly ash, and effectively improves the integral strength of the material through the characteristics of high strength and high rigidity of the two-lime (lime and fly ash) semi-rigid material. In engineering application, the composite cementing material prepared by the invention can be used as a base material in road engineering, has the advantages of long condensation time and micro-expansibility, is low in phosphogypsum price, and can reduce the engineering cost, so that the comprehensive utilization rate of the phosphogypsum is effectively improved.

(3) The manufacturing process is simple and environment-friendly. According to the invention, a large amount of undisturbed phosphogypsum is adopted, and other used materials can be obtained only by simple treatment of natural air drying without a complex pretreatment process; therefore, the manufacturing process of the invention is simple and environment-friendly, and has low production energy consumption and low cost.

In conclusion, the invention has the characteristics of simple process, improved comprehensive utilization rate of the phosphogypsum and the fly ash, excellent compression resistance and water resistance, proper setting time, micro-expansibility and the like.

Detailed Description

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention.

Example 1. The phosphogypsum-fly ash series composite cementing material is prepared from the following raw materials in parts by weight:

phosphogypsum: 53 parts of cement: 7 portions of,

Quick lime: 14 parts of fly ash: 26 parts of,

Curing agent: 0.8 part.

The phosphogypsum is as follows: crushing, drying in a 60 ℃ oven to remove part of free water, and sieving by a square-hole sieve with the diameter of 0.315mm to obtain the phosphogypsum.

The cement is as follows: P.O 42.5 ordinary portland cement.

The main components of the quicklime are CaO and lime special for building materials, the quicklime is sealed for standby, and the exterior of the quicklime is white and powdery.

The fly ash is first-grade fly ash, and the residue of the 45-micron sieve is 12 percent.

The curing agent is a liquid curing agent and is an organic compound mainly composed of elastic styrene-acrylic emulsion.

The preparation method of the phosphogypsum-lime composite cementing material comprises the following steps:

a. uniformly mixing the phosphogypsum, the composite portland cement, the lime and the fly ash to obtain a mixed dry material;

b. respectively doping water with the ratio of a curing agent to water to gel being 0.35 into the dry mixed materials, firstly stirring for 40-70 s at the rotating speed of 60-125 r/min, and then stirring for 60-90 s at the rotating speed of 125-285 r/min to prepare composite slurry; the stirring mode adopts slow stirring firstly, so that the materials are not thrown out of the stirrer to reduce the loss of the materials, and the dry materials are fully contacted with the liquid materials; and then, a fast stirring mode is adopted, so that the materials are uniformly mixed, and slurry with small difference is formed by stirring.

c. Filling the composite slurry into a mold, inserting and tamping, and flattening the surface; placing the mixture into a standard constant humidity curing box for curing to a corresponding age under natural conditions or under the conditions that the temperature is 20 +/-2 ℃ and the relative humidity is 50 +/-3% after demolding, and obtaining the phosphogypsum-fly ash series composite cementing material; the composite cementing material can be applied to road base construction.

The strength detection method of the phosphogypsum-fly ash composite cementing material prepared by the raw materials and the method refers to GB/T17671-1999 Cement mortar Strength test method (ISO method). The compressive strength of the steel is 6.52MPa after 7 days of hardening and 22.5MPa after 28 days of hardening. The 28-day sample had slight expansion and a softening coefficient of 0.76. The initial setting time of the slurry is 555 minutes, the final setting time is 590 minutes, and the setting time of the obtained composite cementing material meets the requirements of GB/T35162-2017 retarding portland cement for road base.

Example 2. The phosphogypsum-fly ash composite cementing material is prepared from the following raw materials in parts by weight:

phosphogypsum: 47 parts of cement: 13 parts of,

Quick lime: 10 parts of fly ash: 30 portions of,

Curing agent: 1 part.

The preparation method of the phosphogypsum-lime composite cementing material comprises the following steps:

a. uniformly mixing phosphogypsum, cement, quicklime and fly ash to obtain a mixed dry material;

b. respectively doping water with the ratio of a curing agent to water to gel being 0.35 into the dry mixed materials, firstly stirring for 40-70 s at the rotating speed of 60-125 r/min, and then stirring for 60-90 s at the rotating speed of 125-285 r/min to prepare composite slurry; the water-glue ratio is as follows: the weight ratio of water to the dry mixed material;

c. filling the composite slurry into a mold, inserting and tamping, and flattening the surface; and (3) after demolding, placing the mixture in a standard constant humidity curing box for curing the mixed mortar test piece under natural conditions or under the conditions that the temperature is 20 +/-2 ℃ and the relative humidity is 50 +/-3% to a corresponding age, thus obtaining the phosphogypsum-fly ash series composite cementing material.

The phosphogypsum is as follows: crushing, drying in a 60 ℃ oven to remove part of free water, and sieving by a square-hole sieve with the diameter of 0.315mm to obtain the phosphogypsum.

The cement is as follows: P.O 42.5 ordinary portland cement.

The main components of the quicklime are CaO and lime special for building materials, the quicklime is sealed for standby, and the exterior of the quicklime is white and powdery.

The fly ash is first-grade fly ash, and the residue of the 45-micron sieve is 12 percent.

The curing agent is a liquid curing agent and is an organic compound mainly composed of elastic styrene-acrylic emulsion.

The strength of the phosphogypsum-lime composite cementing material prepared by the raw materials and the method is tested by referring to GB/T17671-1999 cement mortar strength test method (ISO method), and the compressive strength of the phosphogypsum-lime composite cementing material after being hardened for 7 days is 6.27MPa, and the compressive strength of the phosphogypsum-lime composite cementing material after being hardened for 28 days is 23.5 MPa. The 28d sample had slight expansion and a softening coefficient of 0.75. The initial setting time of the slurry is 470 minutes, the final setting time is 550 minutes, and the setting time of the obtained composite cementing material meets the requirements of GB/T35162-2017 delayed coagulation portland cement for road base.

Example 3. The phosphogypsum-fly ash series composite cementing material is prepared from the following raw materials in parts by weight:

phosphogypsum: 53 parts of cement: 7 portions of

Quick lime: 10 parts of fly ash: 30 portions of

Curing agent: 1.2 parts.

The preparation method of the phosphogypsum-lime composite cementing material comprises the following steps:

a. uniformly mixing the phosphogypsum, the composite portland cement, the lime and the fly ash to obtain a mixed dry material;

b. respectively doping water with the ratio of a curing agent to water to gel being 0.35 into the dry mixed materials, firstly stirring for 40-70 s at the rotating speed of 60-125 r/min, and then stirring for 60-90 s at the rotating speed of 125-285 r/min to prepare composite slurry;

filling the composite slurry into a mold, inserting and tamping, and flattening the surface; and (3) after demolding, placing the mixture in a standard constant humidity curing box for curing the mixed mortar test piece under natural conditions or under the conditions that the temperature is 20 +/-2 ℃ and the relative humidity is 50 +/-3% to a corresponding age, thus obtaining the phosphogypsum-fly ash series composite cementing material.

The phosphogypsum is as follows: crushing, drying in a 60 ℃ oven to remove part of free water, and sieving by a square-hole sieve with the diameter of 0.315mm to obtain the phosphogypsum.

The cement is as follows: P.O 42.5 ordinary portland cement.

The main component of the lime is CaO and special lime for building materials, the lime is sealed for standby, and the outside is white and powdery.

The fly ash is first-grade fly ash, and the residue of the 45-micron sieve is 12 percent.

The curing agent is a liquid curing agent and is an organic compound mainly composed of elastic styrene-acrylic emulsion.

The strength of the phosphogypsum-lime composite cementing material prepared by the raw materials and the method refers to GB/T17671-1999 cement mortar strength test method (ISO method), and the compressive strength of the phosphogypsum-lime composite cementing material after being hardened for 7 days is 6.10MPa, and the compressive strength of the phosphogypsum-lime composite cementing material after being hardened for 28 days is 23.5 MPa. The 28d sample had slight expansion and a softening coefficient of 0.74. The initial setting time of the slurry is 555 minutes, the final setting time is 590 minutes, and the setting time of the obtained composite cementing material meets the requirements of GB/T35162-2017 retarding portland cement for road base.

The above description is only a part of the specific embodiments of the present invention, and the present invention is not limited thereto, and any modification, equivalent replacement, and improvement made on the design concept of the present invention should be included in the protection scope of the present invention, and the design concept of the present invention is also applicable to other industrial by-product gypsum, such as desulfurized gypsum, and the like, and is also within the protection scope of the present invention.