Rational configuration of the latest dry process c

2022-08-05
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Rational configuration of new dry process cement production line system

I. system configuration with the increasing risk of cross infection and the gradual strengthening of regulations and supervision

1 As we all know, cement industry is a resource-based industry. In the period of China's planned economic system, under the premise of planning the regional layout, it should be said that "factories follow the mines". Moreover, due to the small overall scale of the cement industry, there are also high requirements for the grade of resources. Of course, there is also the impact of the maturity of production technology. Simply put, in that period, sufficient scale (reserves) and high-quality raw material resources were the most fundamental conditions for the construction of cement plants. As for the project construction cost and sales cost, they are less important factors

with the establishment and improvement of China's socialist market economy system, the most important factor to evaluate a project is to supply the market at the lowest cost (factory cost + sales cost) on the premise of meeting the requirements of laws and regulations. On the other hand, due to the rapid expansion of the cement industry, there is a great demand for raw material resources. Therefore, raw material resources must be evaluated and implemented according to local conditions

in general, the following elements should be considered:

(1) follow the relevant national policies and regulations on land, mineral resources utilization and environmental protection

(2) there is mature, reliable, economical and reasonable technology for comprehensive utilization of raw material resources (for low-grade products, we have started to use raw materials with Tier-1 suppliers and Fraunhofer igcv1)

(3) meet the quality requirements of cement products (realize the safety of product scheme)

(4) make full use of economically feasible tailings, industrial waste residue and other resources from other industries

(5) optimize project benefits (reduce investment cost and/or production cost) through comprehensive utilization of raw material resources (low-grade raw materials)

(6) reasonable recoverable resource reserves and service life (within the determined project life)

in addition to the special tailings (or waste residue) cement production line attached to large enterprises, it is necessary to implement the mining right of mineral resources while considering the utilization of tailings (or waste residue) to ensure the resource reliability and safety of the project

2. Mining of raw material mines

for the mining of self provided raw material mines, the following principles should be fully considered since the preparation of resource utilization plan:

(1) the delineation of ore volume and mining boundary should take full account of the short-term and long-term planning of the plant, including subsequent mine resources and the expansion of plant scale. It is suggested to implement the plan by stages

(2) the comprehensive utilization scheme of resources should run through the whole process of the project, that is, from design, construction to production

(3) the mining and transportation scheme shall be selected through comparison of multiple schemes in combination with the characteristics of the mine (geology, terrain, landform; climate; scale, etc.). For large-scale mines, the feasibility and rationality of using large-scale mining and transportation equipment should be fully studied

(4) study the rationality of mine working shifts. For large modern mines, if environmental protection permits, work shifts should be increased to maximize the utilization of equipment

3. Crusher system

the following factors shall be considered in the selection of raw material crushing system:

(1) equipment selection shall be based on the characteristics of raw materials (including compressive strength, fragility, metal abrasion, moisture, plasticity index, etc.). Generally speaking, it is not suitable to use single-stage crushing system for hard and abrasive limestone raw materials, but two-stage crushing should be used; The impact crusher should be selected for the silicon aluminum raw materials containing more quartzite (such as gravel)

(2) the configuration of crushing system shall be combined with the development and transportation scheme of the mine. For example, for large mines with a wide face, when Mobile crushers are not used, it may be a more reasonable choice to set up more than one crushing station to shorten the transportation distance of vehicles on the mountain (for more complex mines, ores of different quality can also be mixed into the plant)

(3) the scale of the crushing system should be considered in combination with the transportation mode from the mine to the plant. When the crushing station is set in the mine, its working system shall be consistent with the original stone mining and loading shift of the mine; When it is set in the plant area, it can be divided into three shifts or two shifts

(4) when it is necessary to consider the purchased part of ore (or tailings, waste residue), the relationship with the self mining mine, as well as factors such as ore particle size and quality differences should be considered. Therefore, it may be necessary to set up an independent crushing system in general

(5) in the rainy and humid areas in the south, when the composition of clayey raw materials is relatively stable, the mixed crushing of calcareous raw materials and clayey raw materials is an ideal option for either the crushing of clayey raw materials or the separate storage and homogenization of clayey materials

4. Raw material storage and homogenization

the selection of raw material storage and homogenization system shall depend on the following conditions:

(1) the stage homogeneity of incoming raw material quality and the reliability of sufficient and uniform incoming according to production requirements

the evaluation of the fluctuation of main and harmful components in raw materials and the stability of incoming raw materials is the most basic element to determine the storage and homogenization methods. When purchasing raw materials for civilian purchase and transportation, sufficient raw material storage shall be considered to ensure the reliability of supply and effectively control the cost; When the mine is self-contained and the mining and transportation system is not affected by external factors under normal circumstances, the low value of raw material reserves should be selected. In general, 3 ~ 7 days is appropriate

(2) environmental protection requirements and the impact of relevant climatic conditions

the transportation and stockpiling of raw materials in the Jinan assaying work notice at the end of the factory's October 1 holiday will cause dust to be more easily seen by consumers. Therefore, the EIA report will have requirements on the stockpiling method of raw materials, such as indoor or outdoor storage. In addition, the characteristics of raw materials and climatic conditions are also factors to be considered. For example, when clay is used as aluminosilicate raw material in the south, a long indoor reserve is required (for example, 20 days, or even a month)

(3) when raw materials need to be pre homogenized, a pre homogenization yard shall be set. However, the storage period of the pre homogenization yard should not be too long to avoid occupying too much space and increasing infrastructure investment. In general, it is recommended that calcareous materials be used for 3 ~ 7 days and silicoaluminous materials for 5 ~ 10 days

(4) when multiple production lines share a raw material storage and homogenization system, special attention shall be paid to the capacity matching of stacker reclaimer and the suitability of operation rate, and the shutdown of multiple production lines due to reclaimer failure and planned maintenance shall be avoided

5. Raw material blending system

raw materials shall be fully considered in the design of raw material blending system

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