In May 2022, Yonglun Group's high-quality sand making machine with annual production of 2 million tons, contracted by ADV, was officially put into commercial operation, producing 40-120 mesh high-quality machine made fine sand that meets the quality standards of a Swiss group and national standard machine made sand between 1.6-3.2 modules. Unlike the traditional sand making system of impact crusher and vibrating screen, this project innovatively adopts sand & powder integrated vertical mill + multi-stage sorting and grading machine for the production and sorting of national standard sand and 40-120 mesh high-quality sand. When producing national standard sand, the ground products are directly qualified national standard sand. The particle size distribution of the products can be easily achieved by adjusting the ventilation volume inside the mill, multi-stage sorting and grading machine, operating pressure, etc. The entire system is designed as pneumatic classification, without any product quality fluctuations caused by factors such as screen blockage, high raw material moisture, and wear of wear-resistant plates in traditional systems. With the long-term trust and support of Yonglun, this project has successfully entered commercial operation. It is also hoped that the operation of this project can provide a new direction and ideas for the green and sustainable development of the machine-made sand and gravel industry.

                                                                                                                                                                                                                                                                      Figure 1 Panorama of the Production Line

                                                                                                                                                                                                                                                Figure 2: National standard sand of 2.3-3.2 modulus made by the same equipment

      

                                                                                                                          Figure 3  40-120 mesh high-quality sand

Compared to traditional sand making systems, vertical mill sand and powder making system has the following unique advantages:

• Large single unit production capacity and small production area
• High moisture adaptability, the system can produce normally when the raw material moisture content is 2.5-3.0%.
• One machine with multiple functions, capable of independently producing national standard sand, high-quality fine sand with specific particle sizes, and fine powder with 325 to 400 mesh sizes.
• When 90% of the feed particle size does not exceed 30mm, it can meet the requirements, and the investment cost for front-end crushing is low.
• Flexible product adjustment, allowing for easy adjustment of product types according to market demand.
• The modulus of sand is easy to adjust and can be easily switched between coarse sand, medium sand, and fine sand.
• The amount of fine powder in the tail plate can be easily adjusted, normally controlled at around 5-8%.
• The sand production rate is above 80%, and the average fineness of fine powder is about 325 mesh, which can be directly applied to the mixing plant and has high resource utilization.
• The raw materials are subjected to various grinding methods such as impact, cutting and grinding in the sand making machine, resulting in good particle morphology of the sand and no needle or sheet shaped sand.
• Finished machine made sand has a fine grading at both ends and a coarse grading in the middle. The high proportion of middle particle size avoids the disadvantage of traditional machine made sand with coarse ends and fine middle.
• Pneumatic grading with high accuracy. There is no fluctuation in product quality caused by low efficiency and frequent blockage of the vibrating screen.
• The service life of wear-resistant parts is more than 2 years, avoiding the maintenance trouble to replace the hammer head of traditional impact crusher every 720 hours, and do re-balance after each replacement.
• Full negative pressure operation, safe and environmentally friendly, and clean on-site environment

The production of 40-120 mesh high-quality machine made sand adopts patented technology of multi-stage grading, which can easily achieve the following functions, providing necessary means for owners to adjust the particle size of high-quality machine made sand according to market product requirements:

• The first stage of sorting will separate machine-made sand larger than 1.0mm.
• The second stage sorting separates 0.475-1.0mm machine-made sand.
• The third stage sorting separates 0.15-0.475mm machine-made sand.
• The fourth stage sorting separates the powder below 0.15mm from the machine-made sand.