At present, with the increasing demand for sand and gravel aggregates, the scale of newly built sand and gravel production lines is generally above one million tons per year, and some even reach ten million tons per year. In order to make the whole project achieve the expected production effect, we must consider the following aspects in the early stage of the construction of the new project:
1. The product quality should meet the standard
Product quality can mainly be referred to from the following two aspects:
High quality of finished aggregate
Product quality should not only meet the national standards, but also meet the needs of the market.
High-quality aggregate (coarse aggregate and fine aggregate, fine aggregate is sand), firstly, the particle shape should be good; secondly, the gradation should be reasonable. Especially for machine-made sand, high-quality machine-made sand products must not only meet the sand requirements of commercial concrete, but also meet the requirements of higher standards for ready-mixed mortar sand (ready-mixed mortar is an inevitable requirement in the future. On-site stirring will be phased out over several years). Reasonable continuous grading can meet the needs of high-quality concrete. Neither of them is dispensable.
Soil content up to standard
High-quality concrete has higher and higher requirements for soil content. One of the conditions for the success of the sand and gravel aggregate production line is that the aggregate product of the production line must meet the requirements of soil content. In China, there is a lot of rain in the south, and there is a shortage of water in the north. Some mines contain less surface soil, some contain more soil, and some have additional soil, and so on. Different processes need to be adopted in different situations; otherwise it will cause the failure of the project or increase the huge cost of post-transformation.
The ore characteristics of the mine determine many quality characteristics of sand and stone products, which cannot be changed by changing the process flow of the production line, such as strength index, and the content of needle-like finished products, which is also largely related to the ore characteristics, and the content of alkali active substances, mud content, etc.
After understanding these situations, it is possible to formulate the finished product quality indicators of the production line in a targeted and more objective manner, so as to select a more reasonable production process and main equipment to achieve the predetermined goals of the enterprise. As for other quality indicators, such as particle gradation, stone powder and soil content, apparent density and moisture content, the standard can be achieved by selecting an appropriate production process.
2. Some precautions for the construction of the production line
Good processing technology
The primary condition for the success of the sand and gravel aggregate production line is that the processing technology is good. The good process is reflected in the simplicity of the process, and the equipment is convenient and simple to use and maintain.
Good processing technology is also reflected in the fact that the number of equipment is small and the model is as uniform as possible. The number of equipment is small, the failure points are reduced, and the civil construction cost will be reduced accordingly; the model is unified, the cost of spare parts is low, and the management is convenient. A good process is that the equipment has a high operating rate and a long time of continuous trouble-free operation.
Automation and intelligence
The second important factor in the construction of the production line is to improve the degree of automation, realize intelligence, reduce the number of employees, improve the operation rate of equipment, and improve the continuous operation time without failure.
Meet environmental protection requirements
The third important factor in the construction of the production line is that the production line must meet the environmental protection requirements and meet the green mine construction standards, otherwise it will not survive.
Therefore, it is recommended to choose an experienced design institute to carry out the overall planning and design of the project, or it can be handed over to the design institute for turnkey general contracting.
3. Equipment selection
Whether the equipment selection is reasonable is the primary factor that determines the success of a production line. The equipment selection of the sand and gravel aggregate production line mainly depends on the physical properties of the raw materials (such as the hardness of the raw materials, the abrasiveness index, the soil content, etc.).
Under normal circumstances, any production line that has been designed and selected by a formal and qualified professional design unit will not have equipment selection problems. However, because many production line investors did not find formal design institutes for design, and directly copied the equipment selection of other enterprises for construction, serious problems of unreasonable equipment selection occurred after operation.
This problem is generally difficult to solve by adjusting the process, and the manufacturer has to replace the equipment to ensure the long-term stable and economical operation of the production line.
4. Issues to be considered in the construction of supporting mines
(1) The selection of mines is very important, and the mines should be selected according to the planned product types.
For the selection of mine sites, it is best to have no stripping, good topography and geological conditions, and to find the most economical mine for mining. Of course, if the waste rock stripped from the mine or the tailings after beneficiation can be used, this possibility must be given priority.
(2) It is a great progress to build a reasonable and orderly mine from not paying attention to the construction of supporting mines, and the ultimate goal should be to build the mine into a green mine that meets the relevant national standards, which is a higher scientific requirement for mine industry practitioners.
(3) The construction of the sand and gravel production line should be considered as a systematic project, and the work of the mine is an important part of this system.