When producing prestressed high-strength concrete pipe piles (PHC pipe piles for short), The production process of “secondary curing”, which combines atmospheric steam curing and autoclave curing, is usually adopted. Silica sand powder (or ground fine sand) is used in the production of PHC pipe piles by taking advantage of the characteristics of hydrothermal synthesis reaction during autoclave curing This technology can not only reduce the cement consumption, but also save energy and reduce consumption. At the same time, it can also effectively utilize the abandoned quartz debris resources in the mine, which has good technical and economic benefits. So, what equipment is used to produce the fine ground silica sand for pipe piles? As a professional supplier of silica sand grinding mill machine, HCMilling(Guilin Hongcheng)’s HLM silica sand vertical roller mill has been widely used in the production of finely ground silica sand for pipe piles, which will be described below.

According to the inquiry, Sunwood has used silica sand powder in the production of PHC pipe piles for a long time, but there is no product standard for silica sand powder. In order to ensure the quality of prestressed high-strength concrete pipe piles, better promote the development of the pipe pile industry, promote the wide application of silica sand powder, ensure the quality of silica sand powder, and standardize the silica sand powder market, according to the Document No. 7 of the China Development and Reform Commission in 2005, The building materials industry standard JC/T 950-2005 Silica Sand Powder for Prestressed High-strength Concrete Pipe Piles, drafted by the Civil Engineering Research Institute of Jiaxing University of Suzhou Concrete and Cement Products Research Institute, was released on February 14, 2005 and implemented on July 1, 2005.

So, what equipment can be used to produce the fine ground silica sand for pipe piles to meet the quality requirements of the fine ground silica sand for pipe piles? Silica sand is a hard, wear-resistant and chemically stable silicate mineral with SiO: as the main mineral composition and particle size of 0.020~3.350mm. Its color is milky white, light yellow, brown and gray, hardness 7, brittleness without cleavage, shell-like fracture, grease luster, relative density 2.65. It is insoluble in acid, slightly soluble in KOH solution, melting point 1750C. According to the physical characteristics of silica sand and the quality requirements of fine ground silica sand products for pipe piles. It is considered that the roller, silica sand vertical roller mill and ball mill of silica sand can meet the requirements of silica sand grinding process. When the silica sand processing capacity is 5-10t/h, the roller as the silica sand grinding mill has a large capacity, but the system investment is high. After the secondary pressure breaking, the product size is difficult to meet the requirements, and the price is high. Lack of necessary experimental data. Difficult to meet the requirements; The ball mill is easy to overgrind, the particle size is difficult to control, the energy consumption is large, the production capacity is low, the process flow is complex, and the equipment covers a large area. Although the investment price is low, it is not suitable for the large-scale production of finely ground silica sand for pipe piles. Therefore, HLM silica sand vertical roller mill was finally selected as the production equipment of finely ground silica sand for pipe piles after the mandatory selection of pipe pile customers. As silica sand grinding mill, silica sand vertical roller mill has large capacity, simple system, reliable operation, convenient operation, controllable product fineness and low energy consumption. Its working principle and performance characteristics are as follows:

① Working principle: the silicon sand vertical grinding mill motor drives the grinding disc to rotate through the vertical reducer, and the solid raw materials enter the center of the grinding disc through the air-lock feeding device from the feeding inlet, and are thrown to the periphery of the grinding disc under the action of the centrifugal force field and crushed by the repeated rolling of the grinding roller. The crushed material overflows from the edge of the grinding plate, and the powdery material in it is carried by the high speed airflow rising from the lower part of the machine, and the rising airflow and powdery material pass through the mill. In the upper part of the powder concentrator, under the action of the rapidly rotating rotor, the coarse powder is separated and dropped into the center of the grinding plate for re-grinding, and the fine powder is grinded from the upper part of the silica sand grinding mill with the air flow, and collected in the dust collection device, which is the product. The granular materials that are not carried away by the air flow will overflow the grinding plate and return to the feed inlet of the mill through the external circulation bucket elevator, and then enter the mill for regrinding together with the newly fed raw materials.

② Performance characteristics:

1. It integrates grinding, drying, grading and conveying functions. It is easy to operate and adjust, with high degree of automation and large processing capacity of single machine.

2. The fineness of grinded products can be adjusted, and the powder selection efficiency is high.

3. Low wear, low steel consumption, high wear-resistant material for disc lining and roll surface, long service life.

4. Reliable operation and convenient maintenance. The grinding roller can be turned out of the machine body during maintenance.

5. Low vibration, low noise, no dust during negative pressure operation.

The production process of fine ground silica sand for pipe piles adopts the plan of vertical grinding of silica sand: the process of silica sand grinding mill machine starts from receiving and storing to transporting the finished silica sand, including the receiving and storage of silica sand, warehousing of bucket elevator, grinding of silica sand by vertical grinding, bag dust collection, and outward transportation of finished silica sand.

① Receiving and storage of silica sand: silica sand is transported to the receiving hopper by truck or to the stockyard first and then to the receiving hopper by forklift.

② Bucket elevator warehousing: the raw material is connected with the bucket elevator to lift the silica sand to the silica sand raw material warehouse.

③ Grinding: the silica sand raw material bin is connected with the silica sand vertical roller mill through flange, and the raw materials are fed into the silica sand vertical roller mill from the feed inlet of the silica sand vertical grinding mill for grinding.

④ Bag dust collection: considering environmental protection requirements, bag dust collection device is set at the discharge end of the mill.

⑤ Outward transportation of finished silica sand: qualified silica sand after grinding by ball mill enters the outward transportation belt through the chute at the discharge end, and is transported to the material bin in the batching room, or directly participates in the batching.

HCMilling(Guilin Hongcheng) is the manufacturer of silica sand vertical roller mill. Our silica sand vertical roller mill has been put into production in several fine grinding silica sand production projects for pipe piles, and is deeply recognized and favored by customers. If you want to know more about the equipment configuration and production and operation of finely ground silica sand for pipe piles, please contact HCM for details.