The size of the blocks is irregular, and even scrapped due to cracks, and the yield rate is very low. It is estimated that only 5% to 8% of the mining volume can be processed into timber by the method of drilling and blasting. In the early 1980s, some developed countries in the stone industry had explicitly banned the use of explosive blasting methods to mine stone, and replaced them with advanced technologies such as diamond bead wire saws. It can be said that this is a sign of the modernization of stone mining technology. An important indicator to measure the modernization of stone mining technology is: the number of cubic meters of blocks mined per person per day. People in the International Department believe that China's stone mines have low productivity. The reason is the lack of mechanized equipment, backward mining technology, and poor production management. Some stone mines have an average annual mining volume of only a few hundred to a few thousand cubic meters, and a few stone mines have an annual mining volume of more than 10,000 cubic meters, with an annual per capita output of 6 m3. The equivalent monthly output per capita is only 0.5 m3, which is lower than that of India. As we all know, India is also a big stone producer. However, its granite mine is small in scale and has no modern equipment, so the productivity of stone blocks is very low. Only 1 m3 per person per day. Finland is the largest stone exporter among Scandinavian countries. Its granite mine production system is world-class. It exports at least 250,000 tons of granite every year, and its mine production efficiency is as high as 40 m3 per person per day.
The productivity of stone mines in South Africa is at a medium level, with a daily average of 8-10 m3 per person. Stone processing machinery and equipment In the past ten years, China has made great progress in the development of stone machinery and equipment, and the degree of automation of some stand-alone machines has reached the international advanced level. But in terms of high-end technology and equipment, there is currently no production in China. In terms of the degree of automation of the overall production line of stone enterprises, there is still a gap compared with foreign countries. Some production links still rely on human operations, which not only affects the production efficiency, but also causes unstable factors in the quality of the finished products due to the low quality of employees. Even though most of the stone companies in Italy, the world's stone powerhouse, use highly automated production lines, they still need personnel with certain stone knowledge and experience to master the process parameters of the processing process to produce top-quality stone products. At present, many foreign stone mines, especially granite mines, have fully adopted diamond beaded wire saws for mining blocks, and in the sawing and processing of granite blocks, multi-line diamond beaded wire saws have also been promoted. However, many stone companies in China still use old-fashioned frame saws. One of its significant advantages is that the sawing cost is lower, but it has many disadvantages: ①The assembly cost is high, about four times that of a diamond bead wire saw; ②There are many operators, and at least two people are required to operate.
More people need to work together when replacing the saw blade;
③The cutting speed is slow, and the cutting speed of the old frame saw is only 2cm/h. The cutting speed of the new frame is only 3.5-3.8 cm/h. The cutting speed of the diamond beaded wire saw is as high as 20cm/h, and it may be increased to 30cm/h; the impact of diamond saw blades on stone ④The surface of the plate cut by the frame saw is rough and the flatness is also poor, so the polishing speed is low, 100cm/min, while the surface of the plate cut by the diamond bead wire saw is smoother, and the polishing speed can be as high as 160 cm/min. , Thus reducing the grinding and polishing processing time; ⑤ Energy consumption and material consumption are relatively high;
⑥ The disposal of scrap steel mortar and dust in the work site cause serious environmental pollution. The quality of the finished stone People in the international stone industry believe that the quality of Chinese stone products is not high because the stone processing equipment and techniques used are lagging behind other countries. Take the production of granite facing bricks as an example. Most of the granite blocks mined from mines have irregular shapes and different sizes; diamond circular saw blades with a diameter of 1m and 1.6m are generally used for sawing into granite plates. The quality of the saw blades is not high and the saw is cut. The plate is usually polished and polished with a rocker arm, and the processing is mostly manual operation, that is, the use of a highly automated grinding and polishing machine, the quality of the abrasive used by the matching grinding head is poor; the polished plate is sawed by an ordinary cross-cutting machine A certain size, low degree of automation in the production process. In the 1990s, many European countries have adopted advanced sawing machines and high-quality saw blades. The production of granite facing tiles is almost fully automated. The latest generation of sawing machine is equipped with up to 80 diamond circular saw blades with a diameter of 1m. Due to the use of high-quality diamonds, the saw blade linear speed can be as high as 35m/s, and the feed speed is 17 m/min. The sawing rate of the blade is 1m2/h. In contrast, the sawing machine used in China is generally equipped with only 5 saw blades with a diameter of 1 m or 1.6m, and the quality of the saw blade substrate and diamond is poor, so the saw The linear speed of the blade is limited, 17 m/s or 27 m/s, and the cutting speed is slow, 5m/min. The cutting rate of each saw blade is about /0.3 m2/h.
