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.