Industrial solid waste, that is, solid waste generated in industrial production activities. When it comes to solid waste before, the first reaction is to occupy the land, pollute the environment, and “useless”, but now you have to change your perspective. The editor can tell you for sure , Some “waste” is available and usable, where is it used, how is it used, and what processes are needed? Listen to the editor one by one.
Industrial solid waste classification
Industrial solid waste can be divided into general industrial waste (such as blast furnace slag, steel slag, red mud, non-ferrous metal slag, fly ash, coal slag, sulfate slag, waste gypsum, desulfurization ash, calcium carbide slag, salt mud, etc.) and industrial hazardous solid waste , That is, hazardous solid waste. Among them, we have more contact with the first type, such as waste rock, tailings, and slag.
This article starts with waste rock, understands its source, purpose, and processing equipment, and sees what “magical powers” this humble waste rock has.
Source of waste rock
Waste rock refers to the general term for the mined surrounding rock and rock that contains no ore. In the open pit, the stripped overburden, surrounding rock and gangue without industrial value are generally called waste rock.
Generally include two kinds of stone materials:
The first is the peeling layer of metal and non-metal ore or low-grade ores with no mining value;
The second is the stones in the abandoned mines, such as the waste rock produced during the re-greening of the currently popular abandoned mines.
Uses of waste rock
(1) As a railway ballast
The requirement for railway ballast is not fragile under vibration pressure. Of course, rocks with developed schistosity or bedding are not suitable for use as ballast, while limestone, basalt, etc. are more suitable for railway ballast.
(2) Basic raw materials or mixed raw materials of cement
The basic raw materials of cement are limestone and clay ore, and limestone, claystone, and shale are all common waste rocks in mines. In addition, those with higher amorphous content in waste rock, such as vitreous volcanic rock, tuff, pumice, etc., can also be used as active mixing materials.
(3) Landfill open pit and reclaim
The waste rock is discharged into the open pit that has existed in the past, and then covered with a certain thickness of arable soil to make it arable land. This is the approach that some mines are adopting.
(4) Sand and gravel aggregate
As we all know, sand and gravel aggregate is the largest, indispensable, and irreplaceable basic material for construction of infrastructure projects such as buildings, roads, and bridges. However, the current lack of sand and gravel resources in our country and the extremely imbalanced market supply and demand have led to the rise and rise of sand prices. In the long-term mining and production process of metal and non-metallic mines, a large amount of waste rock is produced, which can be processed into Sand and gravel aggregates ease the contradiction between supply and demand to a certain extent.
The use of waste rock is not only the above mentioned. The current shortage of sand and gravel aggregates and the skyrocketing price. The use of waste rock as sand and gravel aggregate has become one of the hot topics, but some friends may not know much and have concerns. So next we focus on this aspect.
Waste stone sand making equipment and cases
Commonly used waste rock sand production line equipment includes: jaw crusher, counter-attack crusher, cone crusher, hammer crusher, rotary crusher, vertical shaft impact crusher, and auxiliary equipment such as vibrating screen, feeder, belt conveyor and so on. The following is a detailed description of a production line case.
Waste stone sand making case
Artificial sand and gravel production line of a cement plant
Raw materials: low-grade limestone and dolomite, mixed with a small amount of soil
Capacity: 200t/h, daily output (working 16h) 3000t/d
Finished materials: 0～5mm, 5～10mm, 10～20mm, 20～30mm four kinds
The equipment configuration and process are as follows detailed process:
Mine waste rocks smaller than 800mm are loaded into heavy-duty trucks by excavators, transported and dumped into raw material bins.
There is a rod vibrating feeding screen under the raw material bin. The soil and small pieces of waste rock smaller than the rod screen hole are sent to the soil removal screen by the No. 1 belt conveyor for screening, and those smaller than the vibrating screen hole (20mm) Most of it is soil and weathered waste rock, which cannot be used as construction aggregates, but can be used as cushion material for highway roadbed; waste rocks larger than the screen hole (20mm) are returned to the belt conveyor No. 3 by the No. 2 belt conveyor Conveyor, and the ore crushed by the jaw crusher is sent to the suspended iron separator to remove iron, and the ore after iron removal enters the impact crusher for crushing.
The crushed material is conveyed by the No. 4 belt conveyor to the 4th layer of vibrating screen for screening. The raw material (+30mm) larger than the upper screen mesh is returned by the No. 5 belt conveyor to the impact crusher and then crushed. The sieve forms a closed loop.
In actual production, many waste rocks from mines can be used as coarse and medium-grained aggregates. Generally speaking, limestone, fine sandstone, quartzite, granite with relatively fine crystals, diorite, gneiss and basalt, etc. Both are suitable for use as aggregates. The concrete of some airport runways also specifically requires the use of basalt as aggregate, which is related to the high strength of basalt in natural rocks. Therefore, don’t think that waste rock is “useless” anymore. It is definitely a good choice to make the currently popular sand and gravel.