Machine-made Sand Production Process

In order to protect the ecological environment and prohibit excessive and disorderly mining of natural sand, machine-made sand is more and more widely used in the building materials industry. Machine-made sand production has become the focus of the industry.

This paper focuses on the production process of machine-made sand to analyze its cost composition, analyzes the main points of machine-made sand production cost control for the construction input of machine-made sand project and the unit production cost composition of the production stage, and finally puts forward the measures that can be taken to control the production cost of machine-made sand in each stage of the project.

1. Sand Production

1. Production process and product characteristics of machine-made sand

has to go through several technological processes such as crushing, screening, adjustment of stone powder content and necessary shaping, as shown in fig. 1.

Fig. 1 process flow of machine-made sand production

The parent rock obtained from general mining is roughly crushed by a jaw crusher, then crushed by an impact crusher, and finally finely crushed by an impact crusher to make sand, and the rock particles larger than 4.75mm are screened are returned for crushing, and the sand and gravel particles smaller than 4.75mm are then selected according to local conditions. The dry or wet powder removal process is selected to adjust the stone powder content, and finally the product is obtained.

There are differences in particle gradation and surface morphology of machine-made sand obtained by different crushing methods, setting of screening conditions and stone removal methods, resulting in obvious differences in its performance.

Tables 1 and 2 show the characteristics of different products obtained by different sand making methods and different processes for adjusting stone powder content.

Table 1 Grating and Grain Shape Characteristics of Machine-made Sand Produced by Different Sand Making Methods

Table 2 Comparison of Different Methods for Adjusting Stone Powder Content

2. Key points of production cost control of machine-made sand

combined with the production process of machine-made sand, the cost input of machine-made sand production will include the following parts:

is to obtain the input of mining rights (raw materials);

is the investment in the design and construction of machine-made sand production lines and auxiliary facilities (as shown in Figure 2);

is the input in the production stage of machine-made sand, including the input of material consumption, energy consumption, labor, etc. of mining block rock, crushing block rock, screening, adjusting stone powder content and grain shape, etc;

is the investment in environmental protection facilities including dust removal and noise control in the construction and production process;

is the investment in environmental restoration of mining.

1) Key points of input control in the construction phase of the project

Figure 2 shows the proportion of all aspects of capital investment in the construction phase of a machine-made sand enterprise project. As shown in Figure 2, the equipment purchase cost is the largest investment in the machine-made sand project, accounting for about 45%; the second largest investment is construction projects, accounting for about 40% (including land acquisition); other costs include land acquisition and lease (most of the mine side), basic reserve fees and related costs. It can be seen that the cost of equipment purchase and the cost control of construction projects are the key points of input control in the construction phase of the project.

Figure 2 The proportion of investment costs for the construction of machine-made sand projects.

2) Cost control points during normal production of machine-made sand

Figure 3 shows the proportion of each cost per unit of sand production in a company during normal production. Among them, raw materials are the largest cost in the production stage, accounting for 55%. Raw materials generally come from mines or purchased. At present, most enterprises obtain sand-making materials by obtaining mining rights in parent rock mines.

raw materials is the input of mining rights and the cost of using the processing plant after mining and crushing to a certain granularity. Therefore, selecting suitable mining technology, crushing production process and improving the utilization rate of raw materials are the first key points to control the cost of the production stage.

Fig. 3 composition and proportion of production cost per unit product of machine-made sand

manufacturing costs and power energy consumption costs are mainly related to the production process and equipment selection used in the design. According to the comparison of different processes and selection by the design unit, different process schemes and equipment selection affect the production cost by about 5 yuan/ton, of which the main equipment and environmental protection equipment have a greater impact. Therefore, careful consideration should be given to the design, and it is best to find some capable design units to complete the design tasks of the project.

The difference in labor cost is mainly caused by different regions and different degrees of automation of control systems, and the impact on regional sales prices is mainly the level of automation control systems. Financial expenses are mainly investment costs and sales costs.

In addition, the production process of machine-made sand will affect the ecological environment. For example, destroying the local ecological landscape, aggravating soil erosion, possibly causing geological disasters, reducing local biological species, etc. At the same time, mine blasting requires strict safety control, and the dust, noise and other pollution will also affect the normal life of nearby residents. Indirect costs also include compensation for the impact of the project on the local ecological environment and the impact on the daily life of local residents.

2. Machine-made Sand

the ultimate goal of cost control of machine-made sand production enterprises is to produce machine-made sand products required by the market with minimal economic input and obtain high economic benefits.

1. Problems to be paid attention to in the production cost control of machine-made sand

machine-made sand is a part of the production of sand and gravel aggregates. The problems that may be encountered in the production cost control process are the same as the problems that may be encountered in the production of sand and gravel aggregates that also include gravel production. It has its own characteristics. Combined with the analysis results of the production cost composition of machine-made sand, the problems listed in Table 3 should be paid attention to in the process of controlling the production cost of machine-made sand.

Table 3 Summary of Problems to Be Paid Attention to in Production Cost Control of Machine-made Sand

2. Measures to control the production cost of machine-made sand

must go through several stages such as feasibility study, production line design, production line construction, and machine-made sand production. Each stage has an important impact on the cost of machine-made sand production.

1) Feasibility study stage.

Due to the different characteristics of machine-made sand and natural sand, and the different properties of machine-made sand produced by different processes, it is particularly important to understand the use field of machine-made sand and the influence of machine-made sand with different characteristics on its performance;

analyzing the market demand of machine-made sand, fully investigating the local market situation of the project and being familiar with relevant national, local and industry standards are the basis for determining the plan, and it is also an important measure to avoid adjusting the production process and the additional cost of the production line in the production process;

project should conduct sufficient in-depth research on resource reserves, distribution of ore bodies, transportation, water, electricity and other conditions to control the input cost of the construction and production and operation of the machine-made sand production line;

in-depth research and analysis of environmental, social risks and other related impacts to avoid investment other than production costs. Enterprises should take the initiative to disclose the project situation, understand the opinions and demands of relevant parties, and sign agreements when necessary to avoid disputes that may arise in the construction and production process.

2) Production line design stage.

the geological conditions of the construction site of the exploration project, combined with the distribution of ore bodies and mining planning, the layout of the production line is carried out by using topography. Using the terrain height difference of the mining area to carry out the layout of mining methods and production lines can not only save the earthwork leveling cost, but also reduce the civil construction cost of the foundation. A good layout can reduce the investment by nearly 10 million yuan;

the use of drop layout can shorten the length and slope of the belt conveyor, reduce the power configuration and equipment input; according to statistics and reasonable layout, the production cost per ton of products can be saved by about 1.0 yuan; after reasonable design by professional design team, the unit product investment can be reduced by about 30 yuan, and the production cost can be reduced by 3-5 yuan, which is not a small amount.

3) Cost control in the production stage of machine-made sand.

machine-made sand production line is officially put into operation, the unit production cost fluctuation of the product mainly depends on the control of personnel wages and manufacturing costs. There is a large gap between personnel-intensive and professional automated control production costs. The number of automated management personnel is small, personal wages are high, but the per capita unit capacity is large.

reasonable adjustment of staffing, respect for scientific management system and standardized operation, the per capita production capacity of personnel unit output value can reach 1 million tons/year, while personnel-intensive enterprises can achieve 100,000 tons/year, which is very good, and the conversion cost has been reduced by nearly 8 times.

At the same time, due to the operation of scientific monitoring equipment, its operation rate can increase 30%, idling and shutdown can be effectively controlled, and mechanical wear is also reduced by about 10%. The combined cost is reduced by at least 15 yuan/ton. According to the annual output of 3 million tons, the energy consumption cost of about 5 million yuan can be saved every year.

needs to pay attention to the management of the production process, including the technical training of production staff; The maintenance of routine maintenance of equipment is an important way to eliminate potential safety hazards. Adjusting the production volume and type of machine-made sand according to market demand can avoid additional costs caused by unsalable products. In addition, technological development and innovation for production, improving the utilization rate of raw materials, and actively exploring new market areas are all measures to achieve new economic benefits or indirectly control production costs.

sand and gravel aggregate mining industry is developing towards industrialization, standardization and greening, and the market and policy environment of machine-made sand are promising. Adequate market demand research, reasonable design schemes that meet the requirements of product characteristics, and active control of the construction and production process are important means of controlling the production cost of machine-made sand.