A comprehensive utilization process of mineral raw material resources for cement production

Abstract

The present invention discloses a comprehensive utilization process of mineral raw material resources for cement production, and relates to the technical field of limestone mining. The process comprises: coarse screening of ore and separate shipment and storage, and chemical analysis, and the ore is divided into cement stone raw material and building stone raw material according to different CaO content, and the cement stone raw material is crushed and screened, and the qualified cement stone raw material is homogenized in a round pile, and then powdered and elemental analysis is performed again to obtain qualified raw material powder, and other raw materials in the raw material are mixed with the qualified raw material powder and then sent to a homogenization warehouse for homogenization. In addition, the low-grade raw material powder screened out is mixed with qualified raw material powder to make the CaO content meet the requirements and then used as qualified raw material powder. The present invention solves the problem of excessively high waste slag discharge, makes full use of mine resources, and separates the limestone ore powder that does not meet the batching requirements through the process of first grinding limestone and then batching, thereby reducing the influence of limestone component fluctuations on the quality of raw materials and improving the qualified rate of clinker.

Description

Technical Field

[0001] The invention relates to the technical field of limestone mining, in particular to a comprehensive utilization process of mineral raw material resources for cement production. Background Art

[0002] Limestone is a valuable mineral resource that is abundant and widely distributed. As an important building material, it has a long history of mining. In today's industry, limestone is the main raw material for producing cement. In addition, high-grade limestone can also be used in the production of papermaking, rubber, coatings, medicine and other industries.

[0003] Limestone is a sedimentary rock, mainly composed of calcium carbonate and a small amount of magnesium carbonate. my country is very rich in limestone mineral resources. According to statistics, the distribution area of ​​limestone in the country reaches 438,000 square kilometers, of which limestone resources that can be mined as cement raw materials account for about 1 / 4 to 1 / 3 of the total reserves.

[0004] There are often interlayers in the ore layers of limestone mines, especially interlayer rocks with MgO content exceeding 3.5%, which are difficult to be mixed into limestone for utilization and are one of the sources of mine waste. For limestone mines with complex geological structures, interlayers and ore layers are staggered, resulting in a high stripping ratio. In addition, since the grade of limestone ore is not uniform, there is a large proportion of low-grade limestone (generally referring to limestone with a CaO content of less than 45%) in the mined ore. Since its CaO content is lower than the requirement for cement clinker production, it is difficult to be used in cement clinker production and is usually discharged as waste slag, which is the main source of waste slag in limestone mines.

[0005] At present, low-grade limestone is mixed with high-grade limestone with high CaO content through online element analysis and high-low matching methods, and the limestone homogenized material with CaO content that meets the requirements of cement production is obtained through homogenization, realizing the utilization of part of low-grade limestone. However, such a scheme has the following problems: high-grade limestone with a CaO content of more than 48% is a high-quality raw material for producing high-strength cement, and has high market value. In order to utilize low-grade limestone, it is not worth the loss to mix it with limestone with a CaO content of less than 45% for homogenization; secondly, limestone with a large difference in CaO content is difficult to mix evenly during the homogenization process, and the CaO content in the raw materials shipped out of the warehouse fluctuates greatly, making it difficult to accurately control the CaO content in the raw materials. The CaO content of the raw materials after homogenization is often lower than the lower limit requirement for entering the kiln, and the quality of the cement clinker produced is unstable, and the qualified rate is lower than the original production plan.

[0006] The applicant disclosed in CN112759285A a cement clinker prepared using low-grade limestone and a preparation method thereof, which makes use of about 20% of the low-grade limestone produced in the mine and solves the problem of the need to add high-grade limestone in the utilization of low-grade limestone. However, the remaining low-grade limestone waste residue cannot be processed, and the slag discharge problem of the mine cannot be completely solved. In addition, the added low-grade limestone is homogenized in granular form, and the CaO content varies greatly. In the production process, the CaO content of the limestone after homogenization is occasionally too low, which affects the qualified rate of clinker. Summary of the invention

[0007] The purpose of the present invention is to provide a comprehensive utilization process of mineral raw material resources for cement production, so as to solve the problem that the existing limestone mine interlayer and low-grade limestone are difficult to utilize.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A comprehensive utilization process of mineral raw material resources for cement production, comprising the following steps:

[0010] S1: A vibrating screen is set up at the mining face, and a belt conveyor is set up at the entrance of the vibrating screen. The screened limestone is loaded onto the truck through the belt conveyor, and the screened interlayer rock is loaded onto the truck separately through the belt conveyor;

[0011] S2: Separately store the limestone and interlayer rock from different mining faces and conduct chemical analysis. Reserve the limestone with a CaO content of not less than 41.5% as cement stone raw material, and reserve the interlayer rock and limestone with a CaO content of less than 41.5% as building stone raw material;

[0012] S3: Use a crusher to crush the cement stone raw materials in S2, then use a separation device to screen them, and perform element analysis on the screened cement stone raw materials. Cement stone raw materials with a CaO content of not less than 41.5% are sent to the stockpile for round pile homogenization, and cement stone raw materials with a CaO content of less than 41.5% are sent to the building stone raw material warehouse;

[0013] S4: Grind the homogenized cement stone raw material to obtain raw material powder, and perform element analysis again. The raw material powder with a CaO content lower than 44.5% is sent to a low-grade raw material warehouse, and the raw material powder with a CaO content not lower than 44.5% is sent to a qualified raw material warehouse;

[0014] S5: According to the raw material ratio, other raw materials except limestone are batched and ground to obtain batch powder;

[0015] S6: Mix the batching powder and the raw material powder with a CaO content of not less than 44.5% in proportion, and then use a powder selector to separate them to obtain coarse material and fine material. The fine material is sent to the raw material homogenization warehouse for storage, and the coarse material is further ground and then separated by powder selection again.

[0016] Preferably, step S1 further includes separately mining the interlayer with MgO content exceeding 3.5%, loading it onto trucks, and sending it to a building stone raw material warehouse.

[0017] Preferably, the raw material powder in the low-grade raw material warehouse is processed as follows: raw material powder with a CaO content higher than 44.5% is added thereto and mixed evenly, so that the CaO content of the mixed raw material powder is ≥44.5%.

[0018] Preferably, the method for processing the building stone raw materials is as follows: crushing with a crusher and sending to a vibrating screen for separation, crushed stones that meet the size requirements are sent to a building stone storage, and crushed stones that do not meet the size requirements are returned to the crusher for further crushing.

[0019] Preferably, the raw material powder in the low-grade raw material warehouse is graded according to the CaO content, and raw material powders with a CaO content higher than 44.5% are added respectively.

[0020] Preferably, crushed stones with a size of ≤70 mm are sent to the storage, and crushed stones with a size of >70 mm are returned to the crusher for further crushing.

[0021] Preferably, the raw powder in the low-grade raw material warehouse is graded according to the CaO content of [41.5%, 42.5%), [42.5%, 43.5%), and [43.5%, 44.5%), and raw powders with CaO content higher than 44.5% are added respectively.

[0022] Preferably, the raw powder in the low-grade raw material warehouse is graded according to the CaO content of [41.5%, 42.5%), [42.5%, 43.5%), and [43.5%, 44.5%), and the raw powder with a CaO content higher than 44.5% is added respectively. When adding, the raw powder with a CaO content higher than 44.5% is graded according to the CaO content of (44.5%, 45.5%), (45.5%, 46.5%), and >46.5%.

[0023] Preferably, when adding, raw material powders with CaO contents of [41.5%, 42.5%) and >46.5% are mixed, raw material powders with CaO contents of [42.5%, 43.5%) and (45.5%, 46.5%) are mixed, and raw material powders with CaO contents of [43.5%, 44.5%) and (44.5%, 45.5%) are mixed.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] (1) The present invention treats limestone with too low CaO content and high-magnesium interlayer rock produced during the mining process as building stones, thereby solving the problem of excessive waste slag discharge, making full use of mine resources, and reducing waste slag discharge by more than 90%;

[0026] (2) In the process of producing raw materials, the limestone ore powder that does not meet the batching requirements is separated by the process of first grinding the limestone and then batching. The limestone ore powder with the CaO content that meets the requirements is used for batching with the batching powder, thereby reducing the impact of the fluctuation of the limestone composition on the quality of the raw materials and improving the qualified rate of clinker. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The present invention provides a comprehensive utilization process of mineral raw material resources for cement production, aiming to reduce the waste discharge of limestone mines and improve the utilization rate of mine resources. Figure 1 As shown, the process specifically includes the following steps:

[0030] S1: A vibrating screen is set up at the mining face that meets the mining requirements, and a belt conveyor is set up at the entrance of the vibrating screen to send the mined ore into the vibrating screen for coarse screening to remove the interlayer rock mixed in the limestone. The screened limestone is loaded onto a truck through a belt conveyor, and the screened interlayer rock is loaded onto a truck separately through a belt conveyor; before mining, the ore composition of each interlayer is analyzed, and the interlayer with a MgO content exceeding 3.5% is mined and loaded separately and sent to a building stone raw material warehouse as a building stone raw material. The interlayer with a MgO content below 3.5% is mined in combination with limestone to be mixed into the limestone.

[0031] S2: Limestone and interlayer rock from different mining faces are stored separately. When a vehicle loaded with limestone is unloaded, samples are analyzed for each vehicle and the average CaO content is calculated to determine the average grade of the limestone loaded on the vehicle. Limestone with a CaO content of not less than 41.5% is then used as cement stone raw material. There is no need to sample and analyze the CaO content of vehicles loaded with interlayer rock. The interlayer rock and limestone with a CaO content of less than 41.5% are used as building stone raw materials.

[0032] S3: Use a crusher to crush the cement stone raw materials in S2, and then use separation equipment to screen them. The screened materials are crushed until they can be screened. The screened cement stone raw materials are subjected to elemental analysis. The cement stone raw materials with a CaO content of not less than 41.5% are sent to the stockpile for round pile homogenization, and the cement stone raw materials with a CaO content of less than 41.5% are sent to the building stone raw material warehouse. The purpose of this step is to further remove the ore with too low CaO content remaining in the cement stone raw materials, so that the composition of the cement stone raw materials entering the stockpile for homogenization is more uniform.

[0033] S4: Grind the homogenized cement stone raw material to obtain raw material powder, and perform element analysis again. The raw material powder with a CaO content lower than 44.5% is sent to a low-grade raw material warehouse, and the raw material powder with a CaO content not lower than 44.5% is sent to a qualified raw material warehouse. The raw material powder in the low-grade raw material warehouse is processed as follows: add raw material powder with a CaO content higher than 44.5% thereto and mix them evenly, so that the CaO content of the mixed raw material powder is ≥44.5% but not more than 45.0%.

[0034] S5: According to the raw material ratio, other raw materials except limestone are batched and ground to obtain batch powder;

[0035] S6: Mix the batching powder and the raw material powder with a CaO content of not less than 44.5% in proportion, and then use a powder selector to separate them to obtain coarse material and fine material. The fine material is sent to the raw material homogenization warehouse for storage, and the coarse material is further ground and then separated by powder selection again.

[0036] In order to improve the uniformity of the raw material composition, the process of first grinding and then batching was adopted. The limestone ore powder that did not meet the batching requirements was first separated, and the limestone ore powder with a CaO content that met the requirements was used to batch the batching powder, thereby reducing the impact of limestone composition fluctuations on the quality of the raw material.

[0037] The method for processing building stone raw materials is as follows: use a crusher to crush them and send them to a vibrating screen for separation. The crushed stones that meet the size requirements are sent to the building stone storage, and the crushed stones that do not meet the size requirements are returned to the crusher for further crushing. Specifically, the crushed stones with a size of ≤70mm are sent to the building stone storage, and the crushed stones with a size of >70mm are returned to the crusher for further crushing.

[0038] The blending method of low-grade raw materials and qualified raw materials is as follows:

[0039] The raw powder in the low-grade raw material warehouse is graded according to the CaO content, and the raw powder with a CaO content higher than 44.5% is mixed in respectively. The specific process is: the low-grade raw powder in the low-grade raw material warehouse is graded according to the CaO content of [41.5%, 42.5%), [42.5%, 43.5%), [43.5%, 44.5%), and the qualified raw powder with a CaO content higher than 44.5% is graded according to the CaO content of (44.5%, 45.5%), (45.5%, 46.5%), and the CaO content of >46.5% is then mixed in the qualified raw powder with the low-grade raw powder.

[0040] When adding, mix raw material powders with CaO contents of [41.5%, 42.5%) and >46.5%, mix raw material powders with CaO contents of [42.5%, 43.5%) and (45.5%, 46.5%), and mix raw material powders with CaO contents of [43.5%, 44.5%) and (44.5%, 45.5%).

[0041] It is also possible to divide the low-grade raw material powder and the qualified raw material powder into sections according to the difference of 0.5% in CaO content, and blend them according to the following table:

[0042]

[0043] Limestone and the interlayer in the limestone deposit are good building materials. After a company's mine tried out the above scheme, the CaO content of the produced cement stone raw powder was stably controlled between 44.5% and 44.7%, and the qualified rate of cement clinker was increased from the original 98.76% to 99.31%. In terms of the utilization rate of mine resources, all the limestone with a CaO content ≥ 41.5% in the mine was utilized, and the limestone with a CaO content below 41.5% was sold as building stone. About 50%-70% of the interlayer rock was mixed with limestone through mixed mining for the production of cement clinker, and the remaining interlayer rock was sold as building stone through separate mining. Excluding the loss during the mining process, the utilization rate of the interlayer rock reached more than 90%, and the emission of mine waste slag was reduced from the original 350,000-400,000 tons / month to 20,000-30,000 tons / month, mainly debris and miscellaneous ores generated during blasting and mining.

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A comprehensive utilization process of mineral raw material resources for cement production, characterized in that: The steps include: S1: A vibrating screen is set up at the mining face, and a belt conveyor is set up at the entrance of the vibrating screen. The screened limestone is loaded onto the truck through the belt conveyor, and the screened interlayer rock is loaded onto the truck separately through the belt conveyor; S2: Separately store the limestone and interlayer rock from different mining faces and conduct chemical analysis. Reserve the limestone with a CaO content of not less than 41.5% as cement stone raw material, and reserve the interlayer rock and limestone with a CaO content of less than 41.5% as building stone raw material; S3: Use a crusher to crush the cement stone raw materials in S2, then use a separation device to screen them, and perform element analysis on the screened cement stone raw materials. Cement stone raw materials with a CaO content of not less than 41.5% are sent to the stockpile for round pile homogenization, and cement stone raw materials with a CaO content of less than 41.5% are sent to the building stone raw material warehouse; S4: Grind the homogenized cement stone raw material to obtain raw material powder, and perform element analysis again. The raw material powder with CaO content lower than 44.5% is sent to the low-grade raw material warehouse, and the raw material powder with CaO content not lower than 44.5% is sent to the qualified raw material warehouse; S5: According to the raw material ratio, other raw materials except limestone are batched and ground to obtain batch powder; S6: Mix the batching powder and the raw material powder with a CaO content of not less than 44.5% in proportion, and then use a powder selector to separate them to obtain coarse material and fine material. The fine material is sent to the raw material homogenization warehouse for storage, and the coarse material is further ground and then separated by powder selection again; S7: The raw powder in the low-grade raw material warehouse of S4 is processed as follows: the raw powder in the low-grade raw material warehouse is graded according to the CaO content, and raw powder with a CaO content higher than 44.5% is added respectively and mixed evenly, so that the CaO content of the mixed raw powder is ≥44.5%.

2. A comprehensive utilization process of mineral raw material resources for cement production according to claim 1, characterized in that: Step S1 also includes separately mining the interlayer with MgO content exceeding 3.5%, loading it onto trucks, and sending it to a building stone raw material warehouse.

3. A comprehensive utilization process of mineral raw material resources for cement production according to claim 1, characterized in that: The method for processing the building stone raw materials is as follows: crushing the raw materials with a crusher and sending them to a vibrating screen for separation; crushed stones with sizes that meet the requirements are sent to a building stone storage; and crushed stones with sizes that do not meet the requirements are returned to the crusher for further crushing.

4. A comprehensive utilization process of mineral raw material resources for cement production according to claim 3, characterized in that: The crushed stones with a size of ≤70mm are sent to the storage, and the crushed stones with a size of >70mm are returned to the crusher for further crushing.

5. A comprehensive utilization process of mineral raw material resources for cement production according to claim 1, characterized in that: The raw powder in the low-grade raw material warehouse is graded according to the CaO content of [41.5%, 42.5%), [42.5%, 43.5%), and [43.5%, 44.5%), and raw powders with CaO content higher than 44.5% are added respectively.

6. A comprehensive utilization process of mineral raw material resources for cement production according to claim 1, characterized in that: The raw powder in the low-grade raw material warehouse is graded according to the CaO content of [41.5%, 42.5%), [42.5%, 43.5%), and [43.5%, 44.5%), and the raw powder with a CaO content higher than 44.5% is added respectively. When adding, the raw powder with a CaO content higher than 44.5% is graded according to the CaO content of (44.5%, 45.5%], (45.5%, 46.5%], and >46.5%.

7. A comprehensive utilization process of mineral raw material resources for cement production according to claim 6, characterized in that: When adding, mix the raw material powder with a CaO content of [41.5%, 42.5%) and >46.5%, mix the raw material powder with a CaO content of [42.5%, 43.5%) and (45.5%, 46.5%), and mix the raw material powder with a CaO content of [43.5%, 44.5%) and (44.5%, 45.5%).

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