Cement clinker prepared using water-based dust and method and application thereof

Abstract

The application provides a cement clinker prepared from water-based cuttings and a preparation method and application thereof, and the method comprises the following steps: uniformly mixing water-based cuttings and a carbonate modifier according to a first predetermined mass ratio to obtain water-based cutting mixture; mixing the water-based cutting mixture, calcareous raw material, siliceous raw material and ferruginous raw material according to a second predetermined mass ratio to obtain kiln-entrance raw material; and calcining the kiln-entrance raw material to obtain the cement clinker. The preparation method provided by the application uses a carbonate modifier to inhibit the adverse effects caused by sulfates in the water-based cuttings, greatly reduces the adverse effects caused by the water-based cuttings on the cement calcining system, improves the cement calcining efficiency, and increases the mixing amount of the water-based cuttings as the kiln-entrance raw material, and the mixing amount can be increased to 10% of the raw material.

Description

Technical Field

[0001] This invention relates to the field of resource utilization technology for drilling cuttings, specifically to a method for preparing cement clinker using water-based drilling cuttings, a type of cement clinker prepared using water-based drilling cuttings, and an application method for the cement clinker prepared using water-based drilling cuttings. Background Technology

[0002] In recent years, with the increased intensity of oil and gas resource extraction, the output of by-products from oil and gas resources has also been increasing daily. Large-scale oil and gas extraction processes generate a large amount of drilling cuttings. Drilling cuttings have a complex composition, containing inorganic salts, alkalis, heavy metal ions, etc., which can easily pollute surface water and groundwater resources. The disposal of solid waste from drilling cuttings has become one of the bottlenecks restricting the development of oil and gas exploration in my country, and the research and development of effective resource utilization technologies for drilling cuttings is urgently needed.

[0003] There are many ways to utilize drilling cuttings as resources, but the most practical approaches can be broadly categorized into three types: ① preparing unfired bricks; ② preparing sintered bricks; and ③ preparing road materials. However, due to national macro-policy controls, the number of brick and tile factories has been continuously decreasing, and the scale of drilling cuttings processed by these factories cannot meet the ever-increasing demand for drilling cuttings disposal. Furthermore, the amount of drilling cuttings used to prepare road materials is also limited, and large-scale consumption of drilling cuttings cannot be sustained in the long term.

[0004] Currently, some cement companies are using drilling cuttings as cement raw materials and have developed methods for preparing cement or cement clinker using water-based drilling cuttings. For example, Chinese patent document CN108129041A, published on June 8, 2018, entitled "Preparation Method of Calcination of Silicate Cement Clinker Using Oil-Based Drilling Cuttings," describes a method for producing cement using drilling cuttings. This method involves pre-treating diesel-based drilling cuttings, mixing limestone, high-iron aluminum waste rock, pre-treated diesel-based drilling cuttings, and non-ferrous metal slag in a certain proportion, grinding them to prepare raw materials, and then feeding the raw materials into a new type of dry rotary kiln for high-temperature calcination. After cooling, clinker is obtained. Chinese patent document CN110818291A, published on February 21, 2020, entitled "Cement Produced from Drilling Cuttings and Method Thereof and Application," describes a method for producing cement from drilling cuttings. The method includes the following steps: first, solid-liquid separation of drilling cuttings slurry to obtain solid drilling cuttings, and pouring the drilling cuttings into a cuttings pool; stirring and crushing the drilling cuttings with fly ash and homogenizing them; determining the content of chemical components in the product; controlling the proportions and adding it to the cement production process to obtain cement.

[0005] Because drilling cuttings (e.g., water-based cuttings) contain a large amount of BaSO4, their widespread use in the cement industry still presents some problems that need to be addressed: (1) Introducing excessive sulfur into cement raw materials can affect the normal operation of the cement calcination system, such as causing scaling, blockage, and ring formation within the equipment. (2) Introducing excessive sulfur into cement raw materials can affect the amount of liquid phase in the kiln, impacting the formation of the main mineral phases in cement clinker and reducing the strength of cement clinker. Due to the complex composition of drilling cuttings, most cement companies control the amount of drilling cuttings added to less than 3% of the raw meal ratio to reduce the negative impacts of drilling cuttings. Summary of the Invention

[0006] The purpose of this invention is to address at least one of the aforementioned deficiencies in the prior art. For example, one objective of this invention is to provide a method and application for preparing cement clinker using water-based rock cuttings, in order to solve the problem of low water-based rock cuttings content and its adverse effects, and to maximize the water-based rock cuttings content.

[0007] To achieve the above objectives, the present invention provides a method for preparing cement clinker using water-based rock fragments. The method includes the following steps: mixing water-based rock fragments and a carbonate modifier at a first predetermined mass ratio to obtain a water-based rock fragment mixture, wherein the carbonate modifier includes strontium carbonate; mixing the water-based rock fragment mixture, calcareous raw materials, siliceous raw materials, and ferrous raw materials at a second predetermined mass ratio to obtain raw meal for kiln loading; and calcining the raw meal for kiln loading to prepare cement clinker.

[0008] In an exemplary embodiment of the method for preparing cement clinker using water-based rock cuttings according to the present invention, the first predetermined mass ratio of the water-based rock cuttings to the carbonate modifier may be 100:(0.1 to 1).

[0009] In an exemplary embodiment of the method for preparing cement clinker using water-based rock chips according to the present invention, the mass percentage of strontium carbonate in the carbonate modifier may be more than 97%.

[0010] In an exemplary embodiment of the method for preparing cement clinker using water-based rock chips according to the present invention, the calcareous raw material may be limestone.

[0011] In an exemplary embodiment of the method for preparing cement clinker using water-based rock chips according to the present invention, the siliceous raw material may be at least one of shale, sandstone and yellow sand.

[0012] In an exemplary embodiment of the method for preparing cement clinker using water-based rock chips according to the present invention, the iron raw material may be at least one of copper slag, sulfuric acid slag, and sulfur slag.

[0013] In an exemplary embodiment of the method for preparing cement clinker using water-based rock cuttings according to the present invention, the second predetermined mass ratio of the water-based rock cuttings mixture, calcareous raw material, siliceous raw material and ferrous raw material may be (5-10):(75-80):(5-10):(0.5-1.5).

[0014] In an exemplary embodiment of the method for preparing cement clinker using water-based rock chips according to the present invention, the water-based rock chip mixture can be finely ground before the raw meal is prepared for kiln feeding. The particle size of the water-based rock chip mixture can be controlled to have a sieve residue of less than 12% on a 0.08 mm square hole sieve and a sieve residue of less than 1% on a 0.2 mm square hole sieve.

[0015] In another aspect, the present invention provides a cement clinker prepared using water-based rock cuttings, wherein the cement clinker is prepared by the method described above.

[0016] In another aspect, the present invention provides a method for using cement clinker as described above in the preparation of silicate cement.

[0017] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0018] (1) The preparation method provided by the present invention uses a carbonate modifier to suppress the adverse effects of sulfate in water-based rock cuttings, which greatly reduces the adverse effects of water-based rock cuttings on the cement calcination system and improves the cement calcination efficiency.

[0019] (2) The preparation method provided by the present invention significantly increases the amount of water-based rock chips as raw material for kiln feeding. The amount can be increased to 10% of the raw material ratio, saving cement companies the cost of purchasing corresponding raw materials and having direct economic benefits.

[0020] (3) After increasing the amount of water-based rock chips, the quality of the calcined cement clinker still meets the relevant national standards. Detailed Implementation

[0021] In the following sections, the cement clinker, method, and application prepared using water-based rock chips according to the present invention will be described in detail with reference to exemplary embodiments.

[0022] It should be noted that "first," "second," etc., are merely for the convenience of description and distinction, and should not be interpreted as indicating or implying relative importance.

[0023] In existing technologies, because introducing too much sulfur into cement raw materials can affect the strength of cement clinker, most cement companies control the amount of drilling cuttings to less than 3% of the raw meal ratio. Although this can reduce the negative impact of drilling cuttings, it also results in a low resource utilization rate of drilling cuttings, making it impossible to consume water-based cuttings on a large scale in the long term.

[0024] To address the aforementioned problems, this invention modifies drilling cuttings (e.g., water-based cuttings) by adding a carbonic acid modifier, thereby suppressing the adverse effects of sulfates in the drilling cuttings and reducing the effective sulfur content in the cement kiln. The preparation method provided by this invention can significantly increase the amount of water-based cuttings used as raw feed into the kiln, up to 10% of the raw feed proportion, which is of great significance for the effective resource utilization of drilling cuttings.

[0025] To achieve the above objectives, the present invention provides a method for preparing cement clinker using water-based rock chips.

[0026] In an exemplary embodiment of the method for preparing cement clinker using water-based rock cuttings according to the present invention, the method includes the following steps:

[0027] S1. Water-based rock fragments and carbonate modifier are mixed evenly at a first predetermined mass ratio to obtain a water-based rock fragment mixture. The carbonate modifier includes strontium carbonate.

[0028] S2. Mix the water-based rock debris mixture, calcareous raw materials, siliceous raw materials and ferrous raw materials according to the second predetermined mass ratio to obtain raw materials for kiln feeding.

[0029] S3. Calcinate the raw materials fed into the kiln to prepare cement clinker. The calcination temperature is 1250-1450-1250℃ and the calcination time is 20-30 min.

[0030] It should be noted that the purpose of adding the carbonate modifier is to suppress the adverse effects of sulfates in water-based rock fragments. During cement clinker calcination, excessive sulfate content can cause sulfur cycling in the cement calcination system, leading to numerous problems. The SrCO3 in the carbonate modifier decomposes into SrO and CO2 at around 1100℃. The addition of SrO acts as a mineralizer, accelerating the solid-phase reaction of CaO (2CaO + SiO2 = 2CaO·SiO2, 2CaO·SiO2 + SiO2 = 3CaO·SiO2) while lowering the temperature at which the liquid phase appears, thus promoting the formation of silicate minerals (2CaO·SiO2, 3CaO·SiO2). Simultaneously, other silicates react with the iron phase to form an iron-phase solid solution (4CaO + SiO2 + Fe2O3 = C4AF), which can encapsulate CaSO4 at high temperatures, reducing CaSO4 decomposition and effectively minimizing sulfur cycling.

[0031] In this embodiment, the first predetermined mass ratio of water-based rock cuttings to carbonate modifier can be 100:(0.1~1). The advantage of mixing water-based rock cuttings and carbonate modifier according to the first predetermined mass ratio is that, at this mass ratio setting, an appropriate modifier can mitigate the adverse effects of barium sulfate in the water-based rock cuttings, thereby increasing the strength of the calcined clinker. If the modifier dosage is too low, the improvement effect will not be achieved or will be unsatisfactory; if the modifier dosage is too high, it can easily lead to a decrease in the calcinability of the raw meal, affecting clinker calcination.

[0032] In this embodiment, the mass percentage of strontium carbonate in the carbonate modifier can be more than 97%.

[0033] In this embodiment, the calcareous raw material may be limestone. The siliceous raw material may be at least one of shale, sandstone, and yellow sand. The ferrous raw material may be at least one of copper slag, sulfuric acid slag, and sulfur slag.

[0034] It should be noted that the sulfate content in sulfuric acid slag and sulfur slag is very low (below 1%), and the amount of sulfuric acid slag and sulfur slag added is very small (<2%). A small amount of sulfur-containing substances is beneficial to clinker calcination. Excessive sulfur content is required to affect cement clinker calcination. Because water-based rock chips contain a relatively high amount of sulfate, modifiers need to be added after adding water-based rock chips to reduce the impact of sulfate. If water-based rock chips are not added, the sulfur-containing substances introduced by sulfuric acid slag and sulfur slag have almost no negative effect on cement clinker calcination.

[0035] In this embodiment, the second predetermined mass ratio of water-based rock debris mixture, calcareous raw material, siliceous raw material, and ferrous raw material can be (5-10):(75-80):(5-10):(0.5-1.5). This mass ratio of raw materials conforms to the three ratios of cement raw meal proportioning, namely the lime saturation coefficient, silica ratio, and alumina ratio. This cement raw meal proportioning has a wide applicability and conforms to the actual production formulas of most cement enterprises. Under this formula, the vast majority of cement enterprises can produce qualified cement clinker.

[0036] In this embodiment, before preparing the raw meal for kiln feeding, the water-based rock chip mixture can be fed into a drying and grinding equipment for fine grinding to meet the raw material standards for cement enterprises. The particle size of the water-based rock chip mixture can be controlled to have a residue of less than 12% on a 0.08mm square hole sieve and less than 1% on a 0.2mm square hole sieve.

[0037] In another aspect, the present invention provides a cement clinker prepared using water-based rock cuttings, wherein the cement clinker is prepared by the method described above.

[0038] In another aspect, the present invention provides a method for using the cement clinker described above in the preparation of silicate cement.

[0039] To better understand the exemplary embodiments of the present invention described above, further explanation is provided below with reference to specific examples.

[0040] Example 1

[0041] A method for preparing cement clinker using drilling water-injected bedrock cuttings includes the following steps:

[0042] (1) Add a carbonate modifier to the water-based rock cuttings at room temperature. The main component of the carbonate modifier is strontium carbonate, and the addition ratio of the carbonate modifier is 0.1% of the mass of the water-based rock cuttings. Use on-site mixing equipment to fully mix the water-based rock cuttings mixture so that the carbonate modifier is evenly distributed in the water-based rock cuttings, thereby improving the effect of the carbonate modifier.

[0043] (2) The water-based rock chip mixture is further ground using drying and grinding equipment to meet the raw material standards for cement enterprises. Specifically, the particle size of the water-based rock chip mixture is controlled so that the residue on a 0.08mm square hole sieve is less than 12% and the residue on a 0.2mm square hole sieve is less than 1%.

[0044] (3) The dried and ground water-based rock fragment mixture is mixed with the remaining cement raw materials in a certain proportion. The specific proportion (i.e. the second predetermined mass ratio) is water-based rock fragment mixture: limestone: shale: sulfuric acid slag = 5:84:10:1. The mixed cement raw materials are stored in the mixed raw material warehouse.

[0045] (4) The prepared cement raw materials are calcined into cement clinker using the calcination system of the cement enterprise. The calcination temperature range is 1250~1450~1250℃ (for example, first calcined to 1250℃, then heated to 1450℃, and then cooled to 1250℃). The calcination time is 20~30min.

[0046] The strength of the prepared cement clinker is shown in Table 1.

[0047] Table 1 Example 1: Strength of calcined cement clinker

[0048] raw material 3D compressive strength / MPa 28d compressive strength / MPa Example 1: Cement clinker 28.8 57.4

[0049] Example 2

[0050] A method for preparing cement clinker using drilling water-injected bedrock cuttings includes the following steps:

[0051] (1) Add a carbonate modifier to the water-based rock cuttings at room temperature. The main component of the carbonate modifier is strontium carbonate, and the addition ratio of the carbonate modifier is 0.5% of the mass of the water-based rock cuttings. Use on-site mixing equipment to fully mix the water-based rock cuttings mixture so that the carbonate modifier is evenly distributed in the water-based rock cuttings, thereby improving the effect of the carbonate modifier.

[0052] (2) The water-based rock chip mixture is further ground using drying and grinding equipment to meet the raw material standards for cement enterprises. Specifically, the particle size of the water-based rock chip mixture is controlled so that the residue on a 0.08mm square hole sieve is less than 12% and the residue on a 0.2mm square hole sieve is less than 1%.

[0053] (3) The dried and ground water-based rock fragment mixture is mixed with the remaining cement raw materials in a certain proportion. The specific proportion (i.e. the second predetermined mass ratio) is water-based rock fragment mixture: limestone: shale: sulfuric acid slag = 7:83:9:1. The mixed cement raw materials are stored in the mixed raw material warehouse.

[0054] (4) The prepared cement raw materials are calcined into cement clinker using the calcination system of the cement enterprise.

[0055] The strength of the prepared cement clinker is shown in Table 2.

[0056] Table 2 Example 2: Strength of calcined cement clinker

[0057] raw material 3D compressive strength / MPa 28d compressive strength / MPa Example 2 Cement clinker 27.5 56.2

[0058] Example 3

[0059] A method for preparing cement clinker using drilling water-injected bedrock cuttings includes the following steps:

[0060] (1) Add a carbonate modifier to the water-based rock cuttings at room temperature. The main component of the carbonate modifier is strontium carbonate, and the addition ratio of the carbonate modifier is 1% of the mass of the water-based rock cuttings. Use on-site mixing equipment to fully mix the water-based rock cuttings mixture so that the carbonate modifier is evenly distributed in the water-based rock cuttings, thereby improving the effect of the carbonate modifier.

[0061] (2) The water-based rock chip mixture is further ground using drying and grinding equipment to meet the raw material standards for cement enterprises. Specifically, the particle size of the water-based rock chip mixture is controlled so that the residue on a 0.08mm square hole sieve is less than 12% and the residue on a 0.2mm square hole sieve is less than 1%.

[0062] (3) The dried and ground water-based rock fragment mixture is mixed with the remaining cement raw materials in a certain proportion. The specific proportion (i.e. the second predetermined mass ratio) is water-based rock fragment mixture: limestone: shale: sulfuric acid slag = 10:81:8:1. The mixed cement raw materials are stored in the mixed raw material warehouse.

[0063] (4) The prepared cement raw materials are calcined into cement clinker using the calcination system of the cement enterprise.

[0064] The strength of the prepared cement clinker is shown in Table 3.

[0065] Table 3 Example 3: Strength of calcined cement clinker

[0066] raw material 3D compressive strength / MPa 28d compressive strength / MPa Example 3 Cement clinker 28.3 57.1

[0067] In summary, the beneficial effects of the present invention include at least one of the following:

[0068] (1) The preparation method provided by the present invention uses a carbonate modifier to suppress the adverse effects of sulfate in water-based rock cuttings, which greatly reduces the adverse effects of water-based rock cuttings on the cement calcination system and improves the cement calcination efficiency.

[0069] (2) The preparation method provided by the present invention significantly increases the amount of water-based rock chips as raw material for kiln feeding. The amount can be increased to 10% of the raw material ratio, saving cement companies the cost of purchasing corresponding raw materials and having direct economic benefits.

[0070] (3) After increasing the amount of water-based rock chips, the quality of the calcined cement clinker still meets the relevant national standards.

[0071] Although the present invention has been described above in conjunction with exemplary embodiments, it should be clear to those skilled in the art that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for preparing cement clinker using water-based rock cuttings, characterized in that, The method for preparing cement clinker includes the following steps: Water-based rock fragments and a carbonate modifier are mixed evenly at a first predetermined mass ratio to obtain a water-based rock fragment mixture, wherein the carbonate modifier includes strontium carbonate; Water-based rock debris mixture, calcareous raw materials, siliceous raw materials and iron raw materials are mixed according to a second predetermined mass ratio to obtain raw materials for kiln feeding; Calcination of raw materials fed into a kiln produces cement clinker. The first predetermined mass ratio of the water-based rock fragments to the carbonate modifier is 100:(0.1~1). The strontium carbonate in the carbonate modifier accounts for more than 97% by mass. The second predetermined mass ratio of the water-based rock debris mixture, calcareous raw material, siliceous raw material and ferrous raw material is (5~10):(75~80):(5~10):(0.5~1.5).

2. The method for preparing cement clinker using water-based rock cuttings according to claim 1, characterized in that, The calcium-based raw material is limestone.

3. The method for preparing cement clinker using water-based rock cuttings according to claim 1, characterized in that, The siliceous raw material is at least one of shale, sandstone, and yellow sand.

4. The method for preparing cement clinker using water-based rock cuttings according to claim 1, characterized in that, The iron-based raw material is at least one of copper slag, sulfuric acid slag, and sulfur slag.

5. The method for preparing cement clinker using water-based rock cuttings according to claim 1, characterized in that, Before preparing the raw materials for the kiln, the water-based rock chip mixture is ground finely. The particle size of the water-based rock chip mixture is controlled so that the residue on a 0.08mm square hole sieve is less than 12% and the residue on a 0.2mm square hole sieve is less than 1%.

6. A type of cement clinker prepared using water-based rock cuttings, characterized in that, The cement clinker is prepared by the method for preparing cement clinker as described in any one of claims 1 to 5.

7. The application of the cement clinker as described in claim 6 in the preparation of silicate cement.