A Simple and Efficient Measurement for Solid Content by Gas Disp

Abstract: Solid content, which is a crucial physical characteristic of the slurry substance, represents the mass percentage of solids by the weight of slurry. This application note describes a simple and quick method for measuring solid content with a gas pycnometer, which is used to examine the density of slurries with different solid contents.

Introduction

In many industries, such as battery, paint, coating, ceramic, etc., solid content has an impact on both  

the quality of the slurries and the production of downstream products. For instance, the solid content and viscosity of the electrode slurry which determine the final electrochemical properties has a significant impact on the stability of the slurry and the consistency of the battery; Similarly, the solid  content of paints and coatings also has an impact on the quality after film formation. A value that is too high will result in a thick film, whereas a value that is too low might result in no film forming at all.  To ensure the quality of the paste, it is crucial to determine and control the solid content. In order to determine the solid content, the current esting method primarily involves taking a certain weight of slurry and drying it in an oven, then weighing the remaining solids, and dividing the solid weight by the slurry weight. This method, however, is typically time-consuming and does not produce timely analysis results, which slows down the processing of production problems. In addition, the sample after analysis cannot be reused.

By measuring the densities of slurry, dispersion medium, and solids, the gas pycnometer BetterPyc 380 can calculate the solid content of the slurry using the following formula:

This technique, which is based on the gas  displacement method, takes an average of 3 minutes  per test and poses no risk to slurry. In order to verify  the method viability, a group of the clay/water slurries  with known solid content were analyzed by the  BetterPyc 380. Additionally, multiple measurements  were examined to ensure repeatability.

Experimental

Slurry preparation: Place 150 g of clay powder in an  oven for 1 hour to dry out the water. Then the dried  clay powder is weighed and dispersed into deionized  water to create the six clay slurries with calculated solid contents of 2.858%, 8.54%, 11.59%, 19.58%,  27.15% and 40.78%. Sample Test: Dried clay, deionized water, and slurry  are taken, each filling up two thirds of the sample  cup volume. After weighing the mass, the BetterPyc  380 was used to examine the density and the solid  content of the slurry. The specific experimental  conditions are shown in Table 1. The dedicated  lid and sample cup for solid content were used to  measure the densities of deionized water and slurry.  This lid and cup are made of corrosion-resistant  stainless steel, and the cover has a temperature  sensor that can probe inside the liquid to measure its  temperature.

Results and Discussion

Five cycle tests were carried out with the BetterPyc  380 to determine water density of 0.9985 g/cm3 , with  chamber temperature at 20±0.5 °C controlled by a  recirculating water bath. The results are displayed in  Table 1. Given the relationship between water density and temperature, the expected density of water at  20.0°C is 0.9982 g/cm3 . The density of an aqueous  liquid or slurry measured by the BetterPyc 380 is  therefore considered to be an accurate density value.  Prior to examining the solid content of the slurry, the  instrument was used to ascertain the true density of  the dried clay, which came up with a result of 2.7638  g/cm3 .

Subsequently, six samples were each given a solid  content characterization from the instrument.Table 3  shows that the method is very accurate at estimating  the slurry solid content, with an absolute error  between the calculated and measured solid contents  being less than 0.6%. Furthermore, six samples with  different solid contents had deviations that did not  go over 0.05%, demonstrating the high repeatability  of this method. When compared to the traditional  dry weighing method, this method minimizes human error by using a fully automatic true density tester.  Additionally, the single measurement time is less  than 3 minutes, increasing the effectiveness of  testing and analysis.

Conclusion

In this application note, the BetterPyc 380 gas  pycnometer was employed to characterize the  densities of deionized water, dried clay, and water/clay slurries as well as to investigate the slurry  solid content. The experimental results apparently  show that the instrument is capable of examining  the solid content of the slurry with high accuracy.  Second, the results of numerous experiments  showed outstanding repeatability of the instrument,  which was supported by a low standard deviation.  In conclusion, this method is a quality approach for  carrying out solid content characterization because  it is efficient, accurate, and dependable.