In the early days of the founding of the People's Republic of China, China's stone industry started. After the reform and opening up, China's stone industry has developed rapidly. By the 1990s, China's stone exports, output and consumption had reached the first place in the world. In recent years, driven by the rapid development of the national economy, the stone industry has made efforts to overcome the impact of the international financial crisis, and the import and export volume has continued to grow. For example, in 2010, the total import and export volume and quantity of stone materials in China increased significantly compared with that in 2009, reaching US $6.395 billion and 33.86 million tons respectively, 26.26% and 15.41% higher than that in 2009. In 2011, China's stone imports and exports totaled 37.2 million tons, up 9.5% year on year; The import and export volume totaled US $7.6 billion, up 18.0% year on year. From 2012 to 2014, the development of China's stone industry grew rapidly year by year.
The continuous growth of stone imports and exports shows that China has a huge stone consumption market and a strong stone processing capacity, and China has become a real world stone power. However, with the rapid development of the stone industry, some problems in stone processing have gradually emerged. In the process of stone ore processing, there is a serious waste of resources. The arbitrary discharge of stone waste causes environmental pollution and ecological damage, which seriously restricts the sustainable development of the stone industry.
1、 Problems in Stone Processing
China is rich in stone resources, but the traditional production methods are still widely used in the exploitation and processing of stone resources. The backward processing technology and equipment not only affect the stone production efficiency, resulting in a low rate of raw materials and uneven product quality, but also produce a large number of leftovers, sawdust, grinding chips and other wastes in the sawing and grinding process, which directly leads to a serious waste of stone resources. In addition, many stone processing enterprises do not make full use of the waste generated in the processing process, resulting in serious waste of resources. The discharge of stone processing wastewater has caused serious pollution to the surrounding water bodies. The arbitrary discharge of dust in the production process has caused great harm to the health of workers and the surrounding people. In general, the control of stone industry on resources in China is not strong enough at present, and the processing and production of stone have poor environmental protection. It is inevitable for the development of stone industry to take the road of resource conservation, environmental friendliness and sustainable development, which is also the most basic requirement of the times. Efficient utilization of stone resources, improvement and innovation of stone processing technology, and reduction of stone processing pollution are of great significance to the construction of a resource-saving and environment-friendly society.
2、 Efficient utilization of stone resources and measures for energy conservation and emission reduction
2.1 Improve stone processing technology
The measure to reduce the consumption of stone resources in the process of processing is to reduce the generation of stone waste. Stone waste mostly comes from the process of stone sawing and polishing. Apart from human factors, it is mainly determined by processing equipment and technology. Improving sawing methods, using sawing tools with narrow sawing slots, and polishing and grinding equipment with high machining accuracy are the ways for stone enterprises to effectively reduce the waste rate, improve productivity and increase economic benefits. With the emergence of new technologies, stone processing equipment has been continuously improved, and the processing technology has also been continuously improved. The appearance of sand sawing, drag sawing and combined sawing has further advanced the processing technology of plates, significantly improved the production efficiency and effectively controlled the waste of resources. For example, in recent years, the success of the development of ultra-thin high-efficiency combined circular saw blade and the application of automatic continuous polishing mill have greatly improved the production efficiency and reduced the waste generated in the processing. Another major measure to reduce stone consumption is to economize on the use of stone materials. With the improvement of processing technology, stone products are also increasingly thin. Compared with traditional decorative stone plates, thin and ultra-thin stone materials can save stone resources, save energy and protect the environment, greatly reduce the main load and reduce project cost in practical applications. With the maturity of key technologies such as ultra-thin cross section and thickness setting technology, automatic polishing and edge grinding of the plate surface, the minimum thickness of marble plate can reach 2mm, and the maximum specification can reach 1200mm × 2400mm, the thickness of granite plate can be as thin as 3mm, and the specification can be as large as 1200mm × 1200mm。 A new type of stone decorative material, ultra-thin stone composite plate, is composed of ultra-thin stone and base plate.
After the rapid development in recent years, the processing technology level has been constantly improved, gradually showing the remarkable advantages of light weight, high strength, waste recycling and environmental protection, saving mineral resources and other non composite natural stone products.
2.2 Comprehensive utilization of stone waste
In order to reduce the loss of stone resources in the process of processing, in addition to using new equipment and improving the level of processing technology, the most important thing is to research and develop the comprehensive utilization technology of stone waste, so as to make the stone waste resource and high value. At present, the main ways of comprehensive utilization of waste stone are: producing stone mosaic from stone scraps, and producing synthetic stone and artificial special-shaped stone from waste stone and waste stone powder. The process of using waste stone to produce cement based artificial stone, using waste stone to replace pigment to produce cement based artificial stone, not only solves the problem of uneven color, but also makes the waste stone effectively used. Stone waste residue and waste stone powder can also be used to produce sand for casting, chemical product filler, building paint and waterproof materials. For example, the stone like coating is developed by using waste stone powder as the main raw material, adding adhesives and additives. The production process is simple, the investment in production equipment is small, and the utilization rate of stone waste is high. In addition, a new type of material can be made by adding appropriate cement and curing agent into stone powder and stone slag and stirring and pressing the embryo. For example, the unburned base plate of stone composite plate can be prepared by using waste stone and waste stone powder. In addition, the use of waste rock materials and waste rock powder in domestic coal can not only reduce coal consumption, but also play a role in combustion support and desulfurization, reduce the emission of harmful sulfur dioxide gas, and improve indoor and outdoor air quality; An appropriate amount of stone powder is added in the manufacture of the welding electrode to play the role of slagging and prevent the welding pool and air from entering the arc. Waste stone slurry produced in stone processing can be used as cement raw materials after solid-liquid separation and drying, and also as filling materials for production of paints, plastics, rubber, etc.
2.3 Prevention and control of stone dust and waste water pollution
In the process of stone processing, a large amount of dust and waste water are often produced. With the development of society, the call for environmental protection of stone processing industry continues to increase. Stone processing enterprises pay more and more attention to improving the stone factory environment and reducing dust and waste water pollution. In terms of measures to prevent and control dust pollution, some stone enterprises, while using advanced dust-proof processing equipment and equipped with corresponding dust suction devices, also organize technicians to study and improve production technology and innovate processing technology to fundamentally reduce pollutant emissions. For example, during the transportation of artificial stone granular materials, open transportation environment is easy to cause a lot of dust. For example, Foshan Longmeida Stone Industry Co., Ltd., through technological innovation, uses air transport technology and equipment that can ensure that stone particles are transported in a closed state and are relatively mature in technology to transport stone particles. Technicians have innovated the air transport system in several key technologies, and finally solved the problems of environmental pollution and resource waste in stone particle transport, while reducing production energy consumption, The production efficiency is improved.
The vast majority of stone processing enterprises use cutting machines to process stone plates. In the process of processing, clear water cools tools (abrasives), removes debris and cleans the surface, resulting in a large amount of industrial wastewater. As the main pollutant of stone processing wastewater is solid suspended solids, flocculation, sedimentation and other treatment processes are adopted in the technology of processing wastewater treatment, which can achieve the standard discharge of stone processing wastewater and reuse in the plant. For example, Zhang Yunfeng and others reported that the stone processing wastewater was treated by flocculation sedimentation and filtration process. Longmeida Stone Group has established a centralized wastewater treatment system for the stone processing plant in the factory, which reduces dust pollution and improves the recycling of processing wastewater.