Aggregate is the most basic component of concrete. The quality of aggregate determines the quality and economic benefits of concrete. This post shares 9 tips for improving the quality of artificial aggregates.
Suitable Raw Materials
The quality of raw materials directly affects the quality of artificial aggregates. Therefore, qualified stones should be selected first before aggregate processing. Only qualified materials can undergo aggregate processing after radioactivity detection and alkali-aggregate reaction experiments.
In order to improve the quality of aggregates, limestone, dolomite and other materials with medium hardness and low SiO2 content are the first choice for the raw materials for aggregate processing.
Second, choose hard and brittle stones such as granite and tuff. Try not to choose rocks with high compressive strength, toughness and abrasiveness, such as basalt and high-hard quartzite.
When choosing the type of material, it is also important to choose materials with less impurities such as soil and light substances.
- The quality control of raw material mining is divided into raw material cover layer cleaning and charging.
- After the overburden has been cleaned up, it is confirmed by the geological engineer before starting the raw material mining. Raw materials that are severely weathered or that contain a lot of debris or mud are treated as waste, and shall not be discharged into the hopper. Ensure that the quality of raw materials is actively controlled from the source of production and processing.
Selection of Aggregate Processing Equipment
For limestone medium and soft materials, an impact crusher can be used instead of a hammer crusher. Because the aggregates processed by the hammer crusher have a high content of needles and flakes, there are many dark cracks in the aggregate, the crushing value is low, and the firmness loss value is large.
The fine crushing of hard materials such as granite adopts a multi-cylinder cone crusher with laminated crushing function. It can reduce the content of aggregate needle flakes, and is convenient to use the vertical shaft impact crusher to shape the material.
Remove Dirt And Other Impurities Before Coarsely Crushing
The raw materials may be mixed with soil and weathered stones. These impurities with low compressive strength are usually small in particle size. They can be removed in advance by using a bar screen and a soil removal screen, and then sent to the inlet of the jaw crusher to improve the quality of the finished sand and gravel or crushed stone aggregate.
Control The Size Of fine Aggregate Raw Materials
The maximum feed size of the sand making machine used to produce fine aggregate (artificial sand) does not exceed 40 mm. When only artificial sand is produced, stone chips (removal of soil and fine powder) or excess coarse aggregate (5-10/15 mm) are used as raw materials.
Choose The Appropriate Cavity Type And Impeller Speed Of The Sand Making Machine
The sand making machine adopts the “stone hitting stone” crushing cavity type, the rotor edge linear speed is 60-70 m/s, the aggregate shaping effect is good, the sand formation rate is good, and the amount of stone powder produced is small.
After sand making, coarse aggregate can produce artificial sand, finished materials with particle size of 4.75-10 mm and 10-20 mm. Or produce artificial sand, 4 kinds of finished materials with particle size of 4.75-10 mm, 10-16 mm and 16-25 mm.
Choose The Right Screening Equipment
The screening load of the vibrating screen should be appropriate. Use a screening machine with more than two layers. The screen should be square hole style and determine the appropriate screen hole size.
Dry Processing Technology is Preferred
When producing artificial sand for high-performance concrete, if stone chips (except soil and fine powder) or clean rice stone with a particle size of 5-15 mm are used as raw materials, the tower sand making system is adopted.
When artificial sand is used in a concrete mixing station, the moisture content of the raw materials should be less than 3%, and the soil content should be less than 1%. When the finished sand is used for dry-mix mortar, the moisture and soil content of the raw material should be less than 1%.
Choose The Right Dust Control System or Sand Washing Machine
Dry sand making should choose a fine powder separator or dust collector with frequency conversion speed regulation, which can adjust the stone powder content in the finished sand. If the wet process is adopted, the amount of water in the sand washing machine and the screw speed of the sand washing machine should be adjusted reasonably.
Online Installation of Inspection Mechanism Sand Quality Facilities
In order to ensure the long-term stability of the fine aggregate quality, an online inspection device is installed at the outlet of the fine aggregate finished product to detect the quality of artificial sand in real time.
If you have an aggregate processing plant, I hope these techniques to improve the quality of aggregates can help you. If you are planning to develop construction aggregate processing business, contact us for more detailed information on the aggregate processing process and cases.