Jinan Winner brings online particle size analyzer to participate in the 11th Domestic and International Cement Grinding New Technology Exchange Conference

On April 25, 2019, the 11th Domestic and International Cement Grinding New Technology Exchange Conference was held in Wuhan. Jinan Winner Particle Instrument Co., Ltd. participated with a Winner online particle size monitor.

During the meeting, Professor Ren Zhongjing, Chairman of Jinan Winner Particle Instrument Co., Ltd., took the stage to give a report entitled "Application of Multiple Scattering Compensation Technology in Cement Particle Size Detection".

The cement grinding process is a physical effect process of mechanical chemical activation. The cement particle size is continuously ground and reduced during grinding until it is qualified. This is a prerequisite for promoting the hydration reaction of cement particles. However, most domestic cement companies use a common grinding process to prepare cement, which means cement clinker, mixed materials and retarder are mixed in different proportions and transported to the grinding equipment to grind them to a qualified fineness. However, generally One problem is that the ball diameter in the first chamber of the mill is too small, and the ability to crush the coarse powder of the material is insufficient, resulting in a high amount of clinker in the cement, insufficient grinding ability, increased material costs, reduced output, increased power consumption costs, and Undesirable problems such as lowering of cement performance standards. Laser particle size analyzers measure particle size based on the scattering phenomenon of light. When light waves encounter tiny particles while traveling, they will scatter. The smaller the particles, the wider the distribution range of scattered light. There is a certain quantitative relationship between the distribution of scattered light and particle size. Laser particle size analyzers usually use laser as the light source. The laser beam is first focused by an inverted microscope objective, and a pinhole filter is placed at the focus to filter out stray light. The light passing through the pinhole is a pure divergent beam, which becomes parallel light after passing through the collimating lens.

The sample window is illuminated by a parallel laser beam. When the particle sample to be measured is sent to the measurement window using air as the dispersion medium, the laser light will be scattered. The scattered light is focused by the Fourier lens, so that the light with the same scattering angle is gathered at the same point of the photodetector array. Therefore, the photoelectric signal distribution output by the photodetector array represents the distribution of scattered light intensity. The photoelectric signal is amplified and A/D converted and sent to the computer. The computer automatically converts the scattered light intensity distribution into a particle size distribution.

The existing fineness control methods of many enterprises can only roughly determine the proportion of the largest particles in cement. They cannot understand the average particle size of cement and the interval distribution of each particle size in detail and intuitively, let alone determine whether there is "over-powder" in the cement. Grinding” phenomenon. The specific surface area can only be used to judge the coarseness and fineness of cement from the total surface area of cement particles. Theoretically, the higher the specific surface area, the overall particle size of cement particles decreases, and the corresponding sieve residue is relatively smaller. However, in the actual production process, due to different types of mixed materials and grinding processes, the finished cement product often has a high specific surface area and a large fineness, or a low specific surface area but a small fineness sieve residue. Therefore, the specific distribution of different particles in the cement It is impossible to make accurate judgments and provide a comprehensive and accurate basis for adjusting the performance of cement and the gradation of the grinding body of the mill. The method of laser particle size analysis can very accurately determine the content distribution of particles of different particle sizes in cement, and provides the most direct data support for understanding the status of the grinding system of the mill and guiding the adjustment of the grinding body gradation and the transformation of the grinding process technology. , the laser particle size analyzer has become an important tool for cement companies to guide the adjustment process of cement grinding system quality indicators.

Laser particle size analysis is used in cement production and plays a guiding role in the cement grinding and quality control process. Whether it is the adjustment of process parameters, the modification of the inside of the mill, the adjustment of steel ball gradation, etc., it can be effectively used in production, completely changing the traditional cement grinding quality parameter control based only on fineness and specific surface area. The laser particle size analyzer can very intuitively display the distribution range of different particle sizes in finished cement products, which is useful for adjusting cement particle gradation and stably controlling product quality. In particular, industrial by-product resources are more important in the process of cement production, cost reduction, and efficiency improvement. It played a decisive role.

The Winner online laser particle size monitoring system is a powder particle size analysis system that can be used in industrial sites. Each parameter is customized according to customer application requirements. This system mainly consists of the following parts: host system, gas supply system, sampling system, sample Dispersion system, sealed sample window system, material return system, on-site control cabinet system, remote transmission and display system.

The main function of this system is to monitor the particle size distribution of flowing particles in real time and provide accurate control signals. The sampler takes out the powder sample from the production line pipeline and transfers it to the feeder through the unloader. The feeder evenly sends the sample into the sample dispersion pump. The dispersed powder sample enters the instrument through the anti-blocking backflush valve. The host machine sends the tested powder samples back to the production line pipeline through the sample window and the return pump under the action of protective gas. During the test process, the host transmits the measured powder scattering spectrum to the on-site control cabinet in real time. The online particle size analysis software installed in the PC tablet of the on-site control cabinet obtains the particle size distribution of the powder sample through inversion calculations. The on-site control cabinet On the one hand, the obtained particle size distribution data is transmitted to the central control PC through remote communication. The staff can make timely adjustments to the production line based on the particle size distribution data. It can also be directly transmitted to the production line control system to directly adjust the equipment on the production line to operate optimally. Location. The PLC system in the on-site control cabinet is the control center of the entire system. It can control the switch of each component on the system, monitor the operation of the system in real time, and provide timely alarms for abnormal situations.

Aiming at the technical difficulties in online particle size testing of cement, a detailed analysis and study was conducted in combination with the Winner online particle size monitoring system. After several years of on-site use, the results show that online sampling technology, laser particle size analyzer online real-time monitoring, and remote communication technology all meet the requirements of cement. The demand for online particle size testing provides cement companies with a good control over cement fineness standards.