阅读说明：本技术 一种高抗蚀硅酸盐水泥及其生产方法 (High corrosion-resistant portland cement and production method thereof ) 是由 杨义 李少成 覃金英 邓玉莲 刘骥 蒋杉平 唐小春 隆盛康 古巧燕 陆金海 蓝旅 于 2021-08-30 设计创作，主要内容包括：本发明是一种高抗蚀硅酸盐水泥及其生产方法,由以下重量百分比的原料制成：高抗蚀硅酸盐熟料93～97％,天然石膏3～7％；其中,所述的高抗蚀硅酸盐熟料各原料的重量百分比为：石灰石78～82％,高硅砂岩11～15％,硫铁矿6～8％；其工艺过程包括生料制备、料浆脱水、料饼烘干破碎、熟料烧成及输送、水泥粉磨。本发明生产的高抗蚀硅酸盐水泥,3天抗压强度和28天抗压强度均高于国家标准GB/T 31289-2014《海工硅酸盐水泥》中的最高强度等级的要求,具有很好的抗压性能；氯离子扩散系数<0.5×10～(-12)m～(2)/s、28天抗海水侵蚀系数K-(28)>1.0,具有很好的抗海水侵蚀性能和抗海水冲磨能力,适用于各种严苛的海洋条件。(The invention relates to high corrosion-resistant portland cement and a production method thereof, wherein the high corrosion-resistant portland cement is prepared from the following raw materials in percentage by weight: 93-97% of high-corrosion-resistance silicate clinker and 3-7% of natural gypsum; wherein, the high corrosion resistant silicate clinker comprises the following raw materials in percentage by weight: 78-82% of limestone, 11-15% of high-silicon sandstone and 6-8% of pyrite; the technological process includes raw material preparation, slurry dewatering, material cake stoving and crushing, clinker sintering and conveying, and cement grinding. The high-corrosion-resistance portland cement produced by the method has the advantages that the 3-day compressive strength and the 28-day compressive strength are higher than the requirements of the highest strength grade in the national standard GB/T31289-2014 marine portland cement, and the high-corrosion-resistance portland cement has good compressive property; diffusion coefficient of chloride ion<0.5×10 ‑12 m 2 28-day seawater erosion resistance coefficient K 28 >1.0, has good seawater erosion resistance and seawater scouring resistance, and is suitable for various severe ocean conditions.)

1. A high corrosion-resistant portland cement is characterized in that: the material is prepared from the following raw materials in percentage by weight: 93-97% of high-corrosion-resistance silicate clinker and 3-7% of natural gypsum;

the raw material requirements of the high corrosion resistant silicate clinker are as follows: limestone index requirements of calcareous raw materials: CaO is more than or equal to 53 percent, MgO is less than or equal to 1.2 percent, and the granularity is less than or equal to 25 mm; the siliceous raw material is selected from high-silicon sandstone requiring SiO₂More than or equal to 85 percent; selecting Fe as iron raw material₂O₃Pyrite in an amount of not less than 40.0%; wherein the weight percentages of the raw materials are as follows: 78-82% of limestone, 11-15% of high-silicon sandstone and 6-8% of pyrite.

2. The high corrosion resistant portland cement according to claim 1, wherein: the high corrosion resistant silicate clinker comprises the following raw materials in percentage by weight: 80% of limestone, 13% of high-silicon sandstone and 7% of pyrite.

3. The high corrosion resistant portland cement according to claim 1, wherein: the high corrosion resistant silicate clinker ratio is controlled as follows: the lime saturation coefficient LSF is 89 +/-1.5, the silicic acid rate SM is 2.2 +/-0.1, and the alumina rate IM is 0.75 +/-0.1.

4. The high corrosion resistant portland cement according to claim 1, wherein: the material requirements of the natural gypsum are as follows: SO (SO)₃Not less than 35 percent and not less than 5 percent of crystal water.

5. A method for producing the high corrosion-resistant portland cement according to any one of claims 1 to 4, wherein: the method comprises the following steps:

(1) preparation of raw materials: mixing 78-82% of limestone, 11-15% of high-silicon sandstone and 6-8% of pyrite according to a proportion, adding a proper amount of water, grinding by using a ball mill, filtering to prepare slurry with the water content of 32-36%, and uniformly stirring for later use;

(2) and (3) slurry dehydration: dehydrating the slurry obtained in the step (1) by using a vacuum suction filter to form a cake containing 18-20% of water;

(3) drying and crushing a material cake: feeding the material cake obtained in the step (2) into a drying crusher through a feeder, drying the material cake into raw material powder with water content of 1-3% through hot air from the kiln tail, then feeding the raw material powder into a cyclone separator for material gas separation, and feeding the separated raw material powder into a cyclone preheater and a decomposing furnace of a firing system respectively to obtain preheated and decomposed material powder for later use;

(4) and (3) clinker firing: feeding the material powder subjected to preheating decomposition in the step (3) into a rotary kiln, slowly moving towards the kiln head by virtue of the inclination and rotation of the rotary kiln, and sintering the material powder into high-corrosion-resistance silicate clinker by using fire coal in a burning zone, wherein the sintering temperature is 1250-1400 ℃, and the time is 50-70 min; discharging the sintered high corrosion-resistant silicate clinker from the kiln, dropping the clinker into a grate cooler, cooling the clinker to 80-120 ℃, and then feeding the cooled clinker into a hammer crusher to be crushed for later use;

(5) cement grinding: and (4) burdening the high corrosion-resistant silicate clinker obtained in the step (4) by using a cement grinding head electronic belt scale, wherein the burdening is carried out according to the weight ratio of the high corrosion-resistant silicate clinker: and (3) mixing the natural gypsum 93-97: 3-7, and grinding in a mill to obtain the high-corrosion-resistance portland cement.

6. The method for producing a high corrosion-resistant portland cement according to claim 5, wherein: and (3) the hot air from the kiln tail is the hot air from the grate cooler in the step (4), and the temperature of the hot air is 580-620 ℃.

7. The method for producing a high corrosion-resistant portland cement according to claim 5, wherein: the temperature of the decomposing furnace in the step (3) is 850-880 ℃.

8. The method for producing a high corrosion-resistant portland cement according to claim 5, wherein: in the sintered high corrosion resistant silicate clinker in the step (4), f-CaO is less than or equal to 0.8 percent, and the vertical lift weight is more than or equal to 1200 g/L.

9. The method for producing a high corrosion-resistant portland cement according to claim 5, wherein: and (4) the rotating speed of the rotary kiln in the step (4) is 3.2-3.5 rpm, and the push rod speed of the grate cooler is 10-18 times/min.

10. The method for producing a high corrosion-resistant portland cement according to claim 5, wherein: and (4) taking the hot air from the grate cooler in the step (4) as secondary air to enter the kiln again, and also taking the hot air as tertiary air to be pumped into a kiln tail decomposing furnace for combustion and used as hot air for drying raw coal by a coal supply mill.

Technical Field

The invention belongs to the technical field of portland cement, and particularly relates to high-corrosion-resistance portland cement and a production method thereof.

Background

Portland cement is a hydraulic binder made of Portland cement clinker, an appropriate amount of gypsum and a predetermined admixture. Portland cement is a basic raw material in the building industry of China.

With the development of science and technology and the progress of society, the land environment is more and more difficult to meet the requirements of human development, and the ocean becomes a new development target as a wide resource. However, the particularity of the marine environment determines that the construction of marine engineering is necessarily subject to severe examination. The cement-based material is an indispensable important raw material for ocean engineering infrastructure, and the corrosion resistance of the cement-based material is directly related to the durability and service life of ocean engineering. In the marine environment, the durability problem of the cement-based material is very outstanding, and the service life of the marine structure is seriously influenced. The concentration of chloride ions in seawater is about 19g/L, the concentration of sulfate radicals is about 2.2g/L, the chloride ions easily pass through the interior of the cement-based material and migrate to the surface of the steel bar to cause corrosion, and the bond stress of the steel bar is reduced, so that the structure fails; the sulfate attack is the cracking of cement-based materials due to the formation of expansive products such as ettringite, gypsum, etc. Studies have shown that the sulfate attack process is inhibited in the presence of chloride ions, which are a major factor affecting the durability of cement-based materials in marine environments. Therefore, improving the seawater corrosion resistance, especially the chloride ion corrosion resistance, of portland cement is an important method for solving the problem of poor durability of portland cement-based materials in marine environments.

At present, a great deal of research is carried out in China to improve the performance of portland cement, the performance of portland cement in different systems is different in emphasis point, and the application fields are also different. For example, some require low alkali, some require low heat, and others want to be less costly, etc. However, in a complex marine environment, the seawater corrosion resistance of many cement-based materials still needs to be improved.

For example, chinese patent 201610117439.1 discloses a method for preparing marine portland cement, which mainly comprises 38-42% of clinker, 7-9% of gypsum, 32-42% of mineral powder, 5-15% of fly ash, and 4-6% of silica fume, and all the properties of the clinker also meet the relevant standards of marine portland cement, but a large proportion of other raw materials needs to be added, the clinker accounts for only 38-42%, the production cost is increased, and the compressive strength and the seawater corrosion resistance of the clinker are still to be improved. Also as Chinese patent 201610407168.3, a high early strength, high corrosion resistance portland cement and its preparation method is disclosed, comprising 60% -90% of mineral component of high-iron low-calcium cement clinker, 2% -10% of auxiliary functional component, 5% -25% of auxiliary gelling component, 3% -7% of industrial gypsum, produced by separate grinding, co-mixing grinding and other processes. Although the compressive strength of the early cement is improved, the seawater corrosion resistance of the cement is still to be improved.

In order to meet the requirements of high corrosion resistance, high durability and high abrasion resistance of precast concrete for ocean engineering, cement with strong wear resistance, corrosion resistance and frost resistance, particularly good seawater erosion resistance is required to be used.

Disclosure of Invention

In order to solve the problems, the invention provides high-corrosion-resistance portland cement and a production method thereof, wherein the 3-day compressive strength and the 28-day compressive strength of the prepared high-corrosion-resistance portland cement are higher than the requirements of the highest strength grade in the national standard GB/T31289-2014-maritime work portland cement, and the high-corrosion-resistance portland cement has the advantages of high strength grade, high strength, high toughness, high corrosion resistance, high strength, high water resistance, high and high water resistance, high and high water resistanceThe compression resistance is good; diffusion coefficient of chloride ion<0.5×10^-12m²28-day seawater erosion resistance coefficient K₂₈>1.0, has good seawater erosion resistance and seawater scouring resistance, and is suitable for various severe ocean conditions.

In order to achieve the purpose, the scheme provided by the invention is as follows:

the high corrosion resistant portland cement is prepared from the following raw materials in percentage by weight: 93-97% of high-corrosion-resistance silicate clinker and 3-7% of natural gypsum;

the raw material requirements of the high corrosion resistant silicate clinker are as follows: limestone index requirements of calcareous raw materials: CaO is more than or equal to 53 percent, MgO is less than or equal to 1.2 percent, and the granularity is less than or equal to 25 mm; the siliceous raw material is selected from high-silicon sandstone requiring SiO₂More than or equal to 85 percent; selecting Fe as iron raw material₂O₃Pyrite in an amount of not less than 40.0%; wherein the weight percentages of the raw materials are as follows: 78-82% of limestone, 11-15% of high-silicon sandstone and 6-8% of pyrite; the coal used is selected from coal with better coal quality, lower ash content and higher heat productivity.

Preferably, the high corrosion resistant silicate clinker comprises the following raw materials in percentage by weight: 80% of limestone, 13% of high-silicon sandstone and 7% of pyrite.

Preferably, the high corrosion resistant silicate clinker ratio is controlled as follows: lime saturation coefficient LSF is 89 +/-1.5, silicic acid rate SM is 2.2 +/-0.1, and alumina rate IM is 0.75 +/-0.1; wherein LSF represents the degree of silica saturation by calcium oxide to form tricalcium silicate in the clinker, and SM represents SiO in the clinker₂In percentage by weight of (1) and Fe₂O₃And Al₂O₃In percentage, IM represents Al in the clinker₂O₃In percentage by weight of (1) and Fe₂O₃Percentage ratio.

Preferably, the natural gypsum is prepared from the following materials: SO (SO)₃Not less than 35 percent and not less than 5 percent of crystal water.

Further, the production method of the high corrosion resistant portland cement of the invention comprises the following steps:

(1) preparation of raw materials: mixing 78-82% of limestone, 11-15% of high-silicon sandstone and 6-8% of pyrite according to a proportion, adding a proper amount of water, grinding by using a ball mill, filtering to prepare slurry with the water content of 32-36%, and uniformly stirring for later use;

(2) and (3) slurry dehydration: dehydrating the slurry obtained in the step (1) by using a vacuum suction filter to form a cake containing 18-20% of water;

(3) drying and crushing a material cake: feeding the material cake obtained in the step (2) into a drying crusher through a feeder, drying the material cake into raw material powder with water content of 1-3% through hot air from the kiln tail, then feeding the raw material powder into a cyclone separator for material gas separation, and feeding the separated raw material powder into a cyclone preheater and a decomposing furnace of a firing system respectively to obtain preheated and decomposed material powder for later use;

(4) and (3) clinker firing: feeding the material powder subjected to preheating decomposition in the step (3) into a rotary kiln, slowly moving towards the kiln head by virtue of the inclination and rotation of the rotary kiln, and sintering the material powder into high-corrosion-resistance silicate clinker by using fire coal in a burning zone, wherein the sintering temperature is 1250-1400 ℃, and the time is 50-70 min; discharging the sintered high corrosion-resistant silicate clinker from the kiln, dropping the clinker into a grate cooler, cooling the clinker to 80-120 ℃, and then feeding the cooled clinker into a hammer crusher to be crushed for later use;

(5) cement grinding: and (4) burdening the high corrosion-resistant silicate clinker obtained in the step (4) by using a cement grinding head electronic belt scale, wherein the burdening is carried out according to the weight ratio of the high corrosion-resistant silicate clinker: and (3) mixing the natural gypsum 93-97: 3-7, and grinding in a mill to obtain the high-corrosion-resistance portland cement.

Specifically, the hot air from the kiln tail in the step (3) is the hot air from the grate cooler in the step (4), and the temperature of the hot air is 580-620 ℃.

Preferably, the temperature of the decomposing furnace in the step (3) is 850-880 ℃.

Preferably, in the sintered high corrosion resistant silicate clinker in the step (4), the free calcium oxide f-CaO is less than or equal to 0.8 percent, and the vertical lifting weight is more than or equal to 1200 g/L.

Preferably, the rotating speed of the rotary kiln in the step (4) is 3.2-3.5 rpm, and the push rod speed of the grate cooler is 10-18 times/min.

Preferably, the hot air from the grate cooler in the step (4) is used as secondary air to enter the kiln again, and is also used as tertiary air to be pumped into the kiln tail decomposing furnace for combustion and used as hot air for drying raw coal by a coal supply mill.

The high corrosion resistant portland cement produced by the invention is suitable for various severe ocean conditions, and can be used for projects such as harbor wharfs, reservoir dams, offshore bridges, culvert diversion, offshore buildings and the like.

The invention has the following beneficial effects:

1. the high corrosion resistant portland cement produced according to the production method of the invention has the following mineral content components in percentage by mass of tetracalcium aluminoferrite and tricalcium silicate: c₄AF 18～20％，C₃And S45-50%. The invention regulates and controls C₄AF and C₃The content of S reduces the generation amount of hydration products such as hydrated calcium sulphoaluminate, calcium hydroxide and the like, and improves the erosion resistance of sulfate and the like, so that the water-based paint has good durability and seawater scouring resistance.

2. The high corrosion-resistant portland cement produced by the invention has the 3-day compressive strength of more than 23MPa and the 28-day compressive strength of more than 52.5MPa, and both the 3-day compressive strength and the 28-day compressive strength of the high corrosion-resistant portland cement are higher than the requirement of the highest strength grade in the national standard GB/T31289-2014 maritime work portland cement, have good compressive property and are suitable for various severe ocean conditions.

3. The high corrosion resistant Portland cement produced by the invention has the heat of hydration of less than or equal to 230kJ/kg in 7 days, belongs to moderate heat Portland cement, and has the chloride ion diffusion coefficient<0.5×10^-12m²28-day seawater erosion resistance coefficient K₂₈>1.0, the seawater scouring resistance can be improved by more than 30 percent.

4. The invention adopts scientific clinker formulation and 'wet grinding dry burning' semidry process, improves the seawater erosion resistance and compressive strength of cement on the premise of not adding auxiliary materials such as grinding aids and the like, reduces hydration of cement as much as possible, and controls the clinker ratio as follows: lime saturation coefficient LSF is 89 +/-1.5, silicic acid rate SM is 2.2 +/-0.1, and alumina rate IM is 0.75 +/-0.1; f-CaO is less than or equal to 0.8 percent, the vertical lifting weight is more than or equal to 1200g/L, and the mass percentage content C of the tetracalcium aluminoferrite and the tricalcium silicate is controlled₄AF 18～20％，C₃S 45～50％The cement has the characteristics of high iron and low calcium, thereby improving the seawater corrosion resistance of the cement.

5. The invention adopts a production process of a wet-grinding dry-burning semi-dry method, and has the advantages of good homogenization of raw materials, high clinker quality, convenient production transfer, low heat consumption and the like.

6. The raw materials are strictly screened, so that the produced high-corrosion-resistance portland cement is low in free calcium oxide content, high in crystallinity and good in corrosion resistance, and all performances of the high-corrosion-resistance portland cement meet the index requirements of the national standard of GB/T31289-.

Detailed Description

The invention is further described with reference to the following examples:

example 1

The high corrosion resistant portland cement is prepared from the following raw materials in percentage by weight: 97% of high corrosion resistant silicate clinker and 3% of natural gypsum;

the raw material requirements of the high corrosion resistant silicate clinker are as follows: limestone index requirements of calcareous raw materials: CaO is more than or equal to 53 percent, MgO is less than or equal to 1.2 percent, and the granularity is less than or equal to 25 mm; the siliceous raw material is selected from high-silicon sandstone requiring SiO₂More than or equal to 85 percent; selecting Fe as iron raw material₂O₃Pyrite in an amount of not less than 40.0%; wherein the weight percentages of the raw materials are as follows: 78% of limestone, 14% of high-silicon sandstone and 8% of pyrite; the coal used is selected from coal with better coal quality, lower ash content and higher heat productivity.

The high corrosion resistant silicate clinker ratio is controlled as follows: the lime saturation coefficient LSF is 89 +/-1.5, the silicic acid rate SM is 2.2 +/-0.1, and the alumina rate IM is 0.75 +/-0.1. The material requirements of the natural gypsum are as follows: SO (SO)₃Not less than 35 percent and not less than 5 percent of crystal water.

The production method of the high corrosion resistant portland cement comprises the following steps:

(1) preparation of raw materials: preparing raw materials of the high-corrosion-resistance silicate clinker, proportioning the raw materials in proportion by an electronic belt scale through a grinding head of a raw material mill, grinding the raw materials in the mill, matching the ground materials with a certain proportion of water by adopting a wet grinding process, grinding the materials into slurry with the water content of 32% through a ball mill, pumping the slurry into a slurry pump system, accurately proportioning the materials, and putting the slurry into a slurry stirring big pool;

(2) and (3) slurry dehydration: the slurry obtained in the step (1) enters a slurry filtering system through a uniform proportioning pump, and is dehydrated through a vacuum suction filter to form a material cake with 18% of water;

(3) drying and crushing a material cake: feeding the material cake into a drying crusher through a box type feeding machine, drying the material cake into raw material powder with 1% of water by hot air from the tail of a kiln, carrying the raw material powder into a cyclone separator after drying, carrying out material-gas separation, and respectively feeding the separated raw material powder into a cyclone preheater and a decomposing furnace of a firing system to obtain preheated and decomposed material powder for later use; the waste gas from the cyclone separator is sent into a dust remover by a kiln tail fan for purification and then is discharged into the atmosphere through a chimney;

the hot air from the kiln tail is the hot air from the grate cooler in the step (4), and the temperature of the hot air is 620 ℃; the temperature of the decomposing furnace is 870 ℃.

(4) And (3) clinker firing: feeding the material powder after the preheating and decomposition in the step (3) into a rotary kiln, slowly moving towards the kiln head by virtue of the inclination and rotation of the rotary kiln, and sintering the material powder into high-corrosion-resistance silicate clinker by using fire coal in a burning zone, wherein the sintering temperature is 1250 ℃, and the time is 70 min;

discharging the calcined high corrosion resistant silicate clinker from the kiln, falling into a grate cooler, cooling to 80 ℃, entering a hammer crusher at the tail part of the cooler through the reciprocating motion of a push rod, crushing, then discharging onto a chain bucket conveyor, and then conveying to a clinker yard of a combined warehouse by the chain bucket conveyor for later use;

in the sintered high corrosion-resistant silicate clinker, the free calcium oxide f-CaO is less than or equal to 0.8 percent, and the vertical lifting weight is more than or equal to 1200 g/L; the rotating speed of the rotary kiln is 3.2rpm, and the push rod speed of the grate cooler is 10 times/min;

the hot air from the grate cooler is used as secondary air to enter the kiln again and also used as tertiary air to be pumped into the kiln tail decomposing furnace for combustion and used as hot air for drying raw coal by a coal mill;

(5) cement grinding: and (4) burdening the high corrosion-resistant silicate clinker obtained in the step (4) by using a cement grinding head electronic belt scale, wherein the burdening is carried out according to the weight ratio of the high corrosion-resistant silicate clinker: the natural gypsum is mixed according to the ratio of 97: 3, and then the mixture is put into a mill for grinding, thus obtaining the high corrosion-resistant portland cement.

Example 2

The high corrosion resistant portland cement is prepared from the following raw materials in percentage by weight: 93% of high corrosion-resistant silicate clinker and 7% of natural gypsum;

the raw material requirements of the high corrosion resistant silicate clinker are as follows: limestone index requirements of calcareous raw materials: CaO is more than or equal to 53 percent, MgO is less than or equal to 1.2 percent, and the granularity is less than or equal to 25 mm; the siliceous raw material is selected from high-silicon sandstone requiring SiO₂More than or equal to 85 percent; selecting Fe as iron raw material₂O₃Pyrite in an amount of not less than 40.0%; wherein the weight percentages of the raw materials are as follows: 79% of limestone, 15% of high-silicon sandstone and 6% of pyrite; the coal used is selected from coal with better coal quality, lower ash content and higher heat productivity.

The high corrosion resistant silicate clinker ratio is controlled as follows: the lime saturation coefficient LSF is 89 +/-1.5, the silicic acid rate SM is 2.2 +/-0.1, and the alumina rate IM is 0.75 +/-0.1. The material requirements of the natural gypsum are as follows: SO (SO)₃Not less than 35 percent and not less than 5 percent of crystal water.

The production method of the high corrosion resistant portland cement comprises the following steps:

(1) preparation of raw materials: preparing raw materials of the high-corrosion-resistance silicate clinker, proportioning the raw materials in proportion by an electronic belt scale through a grinding head of a raw material mill, grinding the raw materials in the mill, matching the ground materials with a certain proportion of water by adopting a wet grinding process, grinding the materials into slurry with the water content of 33% through a ball mill, pumping the slurry into a slurry pump system, accurately proportioning the materials, and putting the slurry into a slurry stirring large pool;

(2) and (3) slurry dehydration: the slurry obtained in the step (1) enters a slurry filtering system through a uniform proportioning pump, and is dehydrated through a vacuum suction filter to form a material cake with 18% of water;

(3) drying and crushing a material cake: feeding the material cake into a drying crusher through a box type feeding machine, drying the material cake into raw material powder with water content of 2% by hot air from the tail of a kiln, carrying the raw material powder into a cyclone separator after drying, carrying out material gas separation, and respectively feeding the separated raw material powder into a cyclone preheater and a decomposing furnace of a firing system to obtain preheated and decomposed material powder for later use; the waste gas from the cyclone separator is sent into a dust remover by a kiln tail fan for purification and then is discharged into the atmosphere through a chimney;

the hot air from the kiln tail is the hot air from the grate cooler in the step (4), and the temperature of the hot air is 610 ℃; the temperature of the decomposing furnace was 880 ℃.

(4) And (3) clinker firing: feeding the material powder after the preheating decomposition in the step (3) into a rotary kiln, slowly moving towards the kiln head by virtue of the inclination and rotation of the rotary kiln, and sintering the material powder into high-corrosion-resistance silicate clinker by using fire coal in a burning zone, wherein the sintering temperature is 1300 ℃, and the time is 60 min;

discharging the calcined high corrosion resistant silicate clinker from the kiln, falling into a grate cooler, cooling to 100 ℃, entering a hammer crusher at the tail part of the cooler through the reciprocating motion of a push rod, crushing, then discharging onto a chain bucket conveyor, and then conveying to a clinker yard of a combined warehouse by the chain bucket conveyor for later use;

in the sintered high corrosion-resistant silicate clinker, the free calcium oxide f-CaO is less than or equal to 0.8 percent, and the vertical lifting weight is more than or equal to 1200 g/L; the rotating speed of the rotary kiln is 3.3rpm, and the push rod speed of the grate cooler is 12 times/min;

the hot air from the grate cooler is used as secondary air to enter the kiln again and also used as tertiary air to be pumped into the kiln tail decomposing furnace for combustion and used as hot air for drying raw coal by a coal mill;

(5) cement grinding: and (4) burdening the high corrosion-resistant silicate clinker obtained in the step (4) by using a cement grinding head electronic belt scale, wherein the burdening is carried out according to the weight ratio of the high corrosion-resistant silicate clinker: the natural gypsum is mixed according to the ratio of 93: 7, and then the mixture is put into a mill to be ground, so that the high corrosion-resistant silicate cement can be obtained.

Example 3

The high corrosion resistant portland cement is prepared from the following raw materials in percentage by weight: 96% of high-corrosion-resistance silicate clinker and 4% of natural gypsum;

the raw material requirements of the high corrosion resistant silicate clinker are as follows: limestone index requirements of calcareous raw materials: CaO is more than or equal to 53 percent, MgO is less than or equal to 1.2 percent, and the granularity is less than or equal to 25 mm; the siliceous raw material is selected from high-silicon sandstone requiring SiO₂More than or equal to 85 percent; selecting Fe as iron raw material₂O₃Pyrite in an amount of not less than 40.0%; wherein the weight percentages of the raw materials are as follows: 80% of limestone, 13% of high-silicon sandstone and 7% of pyrite; the coal used is selected from coal with better coal quality, lower ash content and higher heat productivity.

The high corrosion resistant silicate clinker ratio is controlled as follows: the lime saturation coefficient LSF is 89 +/-1.5, the silicic acid rate SM is 2.2 +/-0.1, and the alumina rate IM is 0.75 +/-0.1. The material requirements of the natural gypsum are as follows: SO (SO)₃Not less than 35 percent and not less than 5 percent of crystal water.

The production method of the high corrosion resistant portland cement comprises the following steps:

(1) preparation of raw materials: preparing raw materials of the high-corrosion-resistance silicate clinker, proportioning the raw materials in proportion by an electronic belt scale through a grinding head of a raw material mill, grinding the raw materials in the mill, matching the ground materials with a certain proportion of water by adopting a wet grinding process, grinding the materials into slurry with the water content of 35% through a ball mill, pumping the slurry into a slurry pump system, accurately proportioning the materials, and putting the slurry into a slurry stirring large pool;

(2) and (3) slurry dehydration: the slurry obtained in the step (1) enters a slurry filtering system through a uniform proportioning pump, and is dehydrated through a vacuum suction filter to form a cake with 20% of water;

(3) drying and crushing a material cake: feeding the material cake into a drying crusher through a box type feeding machine, drying the material cake into raw material powder with water content of 3% by hot air from the tail of a kiln, carrying the raw material powder into a cyclone separator after drying, carrying out material gas separation, and respectively feeding the separated raw material powder into a cyclone preheater and a decomposing furnace of a firing system to obtain preheated and decomposed material powder for later use; the waste gas from the cyclone separator is sent into a dust remover by a kiln tail fan for purification and then is discharged into the atmosphere through a chimney;

the hot air from the kiln tail is the hot air from the grate cooler in the step (4), and the temperature of the hot air is 600 ℃; the temperature of the decomposing furnace was 860 ℃.

(4) And (3) clinker firing: feeding the material powder after the preheating decomposition in the step (3) into a rotary kiln, slowly moving towards the kiln head by virtue of the inclination and rotation of the rotary kiln, and sintering the material powder into high-corrosion-resistance silicate clinker by using fire coal in a burning zone, wherein the sintering temperature is 1350 ℃ and the time is 55 min;

discharging the calcined high corrosion resistant silicate clinker from the kiln, falling into a grate cooler, cooling to 110 ℃, entering a hammer crusher at the tail part of the cooler through the reciprocating motion of a push rod, crushing, then discharging onto a chain bucket conveyor, and then conveying to a clinker yard of a combined warehouse by the chain bucket conveyor for later use;

in the sintered high corrosion-resistant silicate clinker, the free calcium oxide f-CaO is less than or equal to 0.8 percent, and the vertical lifting weight is more than or equal to 1200 g/L; the rotating speed of the rotary kiln is 3.4rpm, and the push rod speed of the grate cooler is 15 times/min;

the hot air from the grate cooler is used as secondary air to enter the kiln again and also used as tertiary air to be pumped into the kiln tail decomposing furnace for combustion and used as hot air for drying raw coal by a coal mill;

(5) cement grinding: and (4) burdening the high corrosion-resistant silicate clinker obtained in the step (4) by using a cement grinding head electronic belt scale, wherein the burdening is carried out according to the weight ratio of the high corrosion-resistant silicate clinker: the natural gypsum is mixed at a ratio of 96: 4, and is ground in a mill to obtain the high corrosion-resistant portland cement.

Example 4

The high corrosion resistant portland cement is prepared from the following raw materials in percentage by weight: 95% of high corrosion-resistant silicate clinker and 5% of natural gypsum;

the raw material requirements of the high corrosion resistant silicate clinker are as follows: limestone index requirements of calcareous raw materials: CaO is more than or equal to 53 percent, MgO is less than or equal to 1.2 percent, and the granularity is less than or equal to 25 mm; the siliceous raw material is selected from high-silicon sandstone requiring SiO₂More than or equal to 85 percent; selecting Fe as iron raw material₂O₃Pyrite in an amount of not less than 40.0%; wherein the weight percentages of the raw materials are as follows: 82% of limestone, 11% of high-silicon sandstone and 7% of pyrite; the coal used is selected from coal with better coal quality, lower ash content and higher heat productivity.

The high corrosion resistant silicate clinker ratio is controlled as follows: the lime saturation coefficient LSF is 89 +/-1.5, the silicic acid rate SM is 2.2 +/-0.1, and the alumina rate IM is 0.75 +/-0.1. The material requirements of the natural gypsum are as follows: SO (SO)₃Not less than 35 percent and not less than 5 percent of crystal water.

The production method of the high corrosion resistant portland cement comprises the following steps:

(1) preparation of raw materials: preparing raw materials of the high-corrosion-resistance silicate clinker, proportioning the raw materials in proportion by an electronic belt scale through a grinding head of a raw material mill, grinding the raw materials in the mill, matching the ground materials with a certain proportion of water by adopting a wet grinding process, grinding the materials into slurry with the water content of 36% through a ball mill, pumping the slurry into a slurry pump system, accurately proportioning the materials, and putting the slurry into a slurry stirring large pool;

(2) and (3) slurry dehydration: the slurry obtained in the step (1) enters a slurry filtering system through a uniform proportioning pump, and is dehydrated through a vacuum suction filter to form a material cake containing 19% of water;

(3) drying and crushing a material cake: feeding the material cake into a drying crusher through a box type feeding machine, drying the material cake into raw material powder with water content of 3% by hot air from the tail of a kiln, carrying the raw material powder into a cyclone separator after drying, carrying out material gas separation, and respectively feeding the separated raw material powder into a cyclone preheater and a decomposing furnace of a firing system to obtain preheated and decomposed material powder for later use; the waste gas from the cyclone separator is sent into a dust remover by a kiln tail fan for purification and then is discharged into the atmosphere through a chimney;

the hot air from the kiln tail is the hot air from the grate cooler in the step (4), and the temperature of the hot air is 580 ℃; the temperature of the decomposing furnace was 850 ℃.

(4) And (3) clinker firing: feeding the material powder after the preheating decomposition in the step (3) into a rotary kiln, slowly moving towards the kiln head by virtue of the inclination and rotation of the rotary kiln, and sintering the material powder into high-corrosion-resistance silicate clinker by using fire coal in a burning zone, wherein the sintering temperature is 1400 ℃, and the time is 50 min;

discharging the calcined high corrosion resistant silicate clinker from the kiln, falling into a grate cooler, cooling to 120 ℃, entering a hammer crusher at the tail part of the cooler through the reciprocating motion of a push rod, crushing, then discharging onto a chain bucket conveyor, and then conveying to a clinker yard of a combined warehouse by the chain bucket conveyor for later use;

in the sintered high corrosion-resistant silicate clinker, the free calcium oxide f-CaO is less than or equal to 0.8 percent, and the vertical lifting weight is more than or equal to 1200 g/L; the rotating speed of the rotary kiln is 3.5rpm, and the push rod speed of the grate cooler is 18 times/min;

the hot air from the grate cooler is used as secondary air to enter the kiln again and also used as tertiary air to be pumped into the kiln tail decomposing furnace for combustion and used as hot air for drying raw coal by a coal mill;

(5) cement grinding: and (4) burdening the high corrosion-resistant silicate clinker obtained in the step (4) by using a cement grinding head electronic belt scale, wherein the burdening is carried out according to the weight ratio of the high corrosion-resistant silicate clinker: the natural gypsum is mixed according to the ratio of 95: 5, and then the mixture is put into a mill for grinding, thus obtaining the high corrosion-resistant silicate cement.

Comparative example 1: the production method of the embodiment 4 in the Chinese patent CN 106082724B.

The high early strength and high corrosion resistance portland cement is prepared from a mineral component containing high-iron low-calcium cement clinker, an auxiliary functional component, an auxiliary gelling component and industrial gypsum, wherein the components in percentage by weight are as follows: 90% of mineral component of high-iron low-calcium cement clinker, 2% of auxiliary functional component, 5% of auxiliary gelling component and 3% of industrial gypsum (produced by processes of single grinding, common mixed grinding and the like).

The auxiliary functional component is layered zinc-aluminum double metal hydroxide. The auxiliary gelling component is a mixture of slag micro-particles and steel slag with the mass ratio of 1:1, and the specific surface area of the auxiliary gelling component is not less than 7800m 2/kg. The industrial gypsum is fluorgypsum.

The mineral components of the high-iron low-calcium cement clinker are mainly prepared from the high-iron low-calcium silicate cement clinker and the high-iron low-calcium Q-phase cement clinker according to the ratio of 10: 1.

The high-iron low-calcium silicate cement clinker is prepared from a calcareous raw material, an aluminum-silicon raw material, an iron raw material, a mineralizer and an activating agent, and the high-iron low-calcium silicate cement clinker comprises the following components in percentage by mass: 62.86% of marble, 13.56% of clay, 17.35% of shale and 6.23% of iron tailings, wherein the mineralizer is seed crystal clinker and copper slag, and the mass of each mineralizer accounts for 1/2%; the activating agent is in the high titanium slag. The mineralizer is doped with 2 percent of the total mass of the calcareous raw material, the aluminum-silicon raw material and the iron raw material, and the activator is doped with 2 percent of the total mass of the calcareous raw material, the aluminum-silicon raw material and the iron raw material; the product is sintered at 1350 ℃, the holding time at the sintering temperature is 2 hours, and the cooling mode is rapid cooling.

The high-iron low-calcium Q-phase cement clinker is prepared from magnesium slag, a calcium raw material, an aluminum-silicon raw material and an iron raw material, and the mass percentages are as follows: 2.23 percent of magnesium slag, 56.72 percent of limestone, 27.63 percent of coal gangue, 13.42 percent of sludge and 10.36 percent of bauxite; and firing at a temperature 1260, wherein the holding time at the firing temperature is 2 hours, and the cooling mode is rapid cooling.

The preparation method comprises the following steps:

1) mixing the high-iron low-calcium silicate cement clinker and the high-iron low-calcium Q-phase cement clinker according to the proportion to obtain mineral components of the high-iron low-calcium cement clinker;

2) selecting mineral components of the high-iron low-calcium cement clinker, auxiliary functional components, auxiliary gelling components and industrial gypsum according to the proportion; firstly, separately grinding the mineral component of the high-iron low-calcium cement clinker, the auxiliary functional component, the auxiliary gelling component and the industrial gypsum, then mixing (in a homogenizing device), and grinding to obtain the high early-strength and high-corrosion-resistance portland cement.

The high corrosion-resistant portland cements produced according to the methods of examples 1 to 4 and comparative example 1 were subjected to quality inspection. The compressive strength for 3 days and 28 days is detected according to the GB/T17671-1999 standard, the hydration heat for 7 days is determined according to GB/T12959-2008, the chloride ion diffusion coefficient is determined according to JC/T1086-2008, and the seawater corrosion resistance coefficient for 28 days is determined according to GB/T749-2008. The detection data is shown in the following table 1, and the requirements for strength in GB/T31289-2014 maritime work portland cement are shown in the following table 2.

TABLE 1 test results of highly corrosion-resistant Portland Cement of examples 1 to 4 and comparative example 1

TABLE 2 marine Portland cement compression strength values

Strength grade	3d compressive Strength (MPa)	28d compressive Strength (MPa)
			32.5L	8.0	32.5
32.5	10.0	32.5
			42.5	15.0	42.5

As can be seen from tables 1 and 2, the properties of the high corrosion-resistant portland cement produced in embodiments 1 to 4 of the invention all meet the index requirements of the national standard of GB/T31289-2014 'maritime work portland cement'. Wherein the 3-day compressive strength is 24.5-25.1 MPa, the 28-day compressive strength is 55.4-56.1 MPa, and the requirement of the marine Portland cement for the compressive strength with the strength grade of 42.5 is as follows: the compressive strength of the high-corrosion-resistance portland cement reaches 15.0 in 3 days and 42.5 in 28 days, so that the compressive strength of the high-corrosion-resistance portland cement is higher than the requirement of the highest strength grade in the national standard. The heat of hydration in 7 days is 210-230 kJ/kg, and belongs to moderate-geothermal Portland cement; the chloride ion diffusion coefficient of the material is 0.45 multiplied by 10 in 28 days^-12～0.48×10^-12m²S is far less than 1.5 multiplied by 10 required in the marine Portland cement^-12m²S, also less than 0.68X 10 in comparative example 1^-12(ii) a 28-day seawater erosion resistance coefficient K₂₈1.12-1.15, which is higher than the requirement of 'marine Portland Cement' by not less than 0.99 and is also higher than 1.05 in comparative example 1, which shows that the produced high corrosion resistance Portland cement produced by the invention has seawater corrosion resistanceThe performance is better.

Although the present invention has been described with reference to the specific embodiments, it should be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.