What is comprehensive utilization and processing technology of ore tailings?

1. Used to produce heavy calcium carbonate

Heavy calcium carbonate mainly uses marble, calcite and dolomite as the main raw materials. The requirements are high purity, low iron content, no sulfur, and harmless to the human body.During mining, the symbiotic ore bodies in the surrounding rocks can generally be mined and utilized. There are fragments of large calcite veins or dolomite veins or pure marble and dolomite in the waste rock of some mine deposits, which can be selected from the waste rock as this raw material. After simple crushing, grinding and packaging, qualified heavy calcium powder can be obtained.

2. Used to produce prefabricated component admixtures

In the field of prefabricated components, a large amount of limestone powder in mine waste rock tailings can also be used as concrete and cement admixtures. The “Quality Control Standard for Precast Concrete Components” (DB11/T1312-2015) requires that when precast concrete uses mineral admixtures such as limestone powder, its performance should meet the requirements of relevant standards. Studies have shown that in the production of vibration-free self-compacting precast concrete components, limestone powder can effectively improve the fluidity and resistance to separation of concrete, and has a significant effect on concrete shaping, solving problems such as insufficient raw materials. In addition to the above-mentioned limestone powder, dolomite, granite, etc. whose properties are close to those of limestone can also be used as admixtures for concrete and cement after being ground to a qualified fineness by a grinding mill.

3. Used in the production of stone powder for desulfurization

At present, limestone desulfurization is the most important method for flue gas desulfurization in power plants in my country due to its mature technology and stable operation. The mine waste rock powder produced during the sand and gravel mining process is further ground and processed by the ore grinding machine, which can effectively reduce the cost of the desulfurization process of the power plant and provide a good market for the comprehensive utilization of mine waste rock.

4. Materials used to directly degrade heavy metals during sewage treatment

The principle of purifying sewage from ore tailings is: adding ore tailings slime to urban sewage, the slime can adsorb heavy metal ions to the surface of the tailings, forming a precipitate that is separated from the water, and is more complete than ordinary hydroxide adsorption and separation.Studies have shown that if the adsorption is purely surface binding, then several pounds of metal can be adsorbed per ton of tailings; if it can also act as a chemical reaction, such as pyrrhotite has a chemical effect on mercury ions, then each ton of tailings can absorb hundreds of pounds of metal.

5. Used as filter material for physical treatment of sewage

Physical treatment of sewage is often used in primary treatment to remove suspended solids or turbidity in sewage. There are many physical methods, among which the commonly used filter materials for filtration methods are quartz sand, garnet particles, magnetite particles, dolomite particles, granite particles, etc. There are also those who use gold ore abroad. These substances are common in ore tailings.

6. Used as basic raw materials for cement

The basic raw materials of cement are limestone and clay minerals. Limestone and claystone (shale, etc.) are common waste rocks in mines, or tailings containing corresponding components can also be used as basic raw materials. It should be noted that for the utilization of limestone and claystone, do not mechanically copy the grade index requirements in past specifications.

7. Used as ceramic raw materials

Research results show that many ore tailings can not only be used to make daily ceramics or industrial ceramics, but can even be used to make ceramic handicrafts. Some research shows that some tailings can also be used to make glazes. For example, kaolin tailings are used to make 250 mesh and 325 mesh kaolin porcelain clay, which is a general ceramic raw material.

8. Used to produce sand and gravel aggregates

During the long-term mining and production process, mines produce a large amount of waste rock and tailings. The use of these tailings resources can completely or partially replace sand and gravel aggregates. Especially this year, national and local governments have issued guidance on the development of the sand and gravel industry, encouraging the use of tailings and waste rock to produce manufactured sand. Generally speaking, limestone (those without amorphous SiO2 and MgO), fine sandstone, quartzite, granite with relatively fine crystallization, diorite, gneiss and basalt are all suitable as aggregates.

In the field of mining, industrially developed countries in the world have set waste-free mines as their development goals, and the degree of comprehensive utilization of mine waste rock as a measure of a country’s scientific and technological level and economic development. The comprehensive utilization rate of waste rock in mines can reach more than 60%, and some European countries are already developing towards the goal of waste-free mines. The comprehensive utilization of mineral solid waste not only pursues economic benefits, but also comprehensively considers the comprehensive recycling rate of resources and the protection of the ecological environment. With the development of science and technology and the mutual penetration between disciplines, the ways to utilize tailings will become wider and wider.