Introduction:
Many factories are used to putting all the decoagulant at once when pulping. However, this practice can easily lead to uneven distribution of charges on the surface of the particles, causing "local supersaturation" or "pseudo-coagulation" of the slurry ". In the high-pressure grouting environment, this small rheological deviation will be amplified,Cause the molding cycle to extend or mold cracking.
The best time to add: Step-by-step collaborative solution
The Sunlets technical team found that step-by-step addition is the key to maintain the long-term stability of the slurry:
Pre-mixing stage (before the start of the ball mill): Before the ball mill is charged, 60% of the total proportion of the decoagulant is dissolved in water.The main task at this stage is to reduce the surface tension of the water to ensure that the clay particles are quickly wetted at the moment they enter the ball mill to prevent agglomeration.
In the middle of fine grinding (when the ball grinding process is 70%)
At this time, the specific surface area of the particles increases sharply, and 30% decoagulant needs to be added to cover the surface of the newly generated particles,Prevent secondary agglomeration as the particles become finer.
Aging and fine-tuning stage:
The last 10% of the decoagulant should be added in a small amount according to the real-time viscosity test results during the aging process of the slurry entering the storage tank.
Scientific addition method: from "volume method" to "concentration dynamic compensation"
The traditional volume addition method ignores the moisture fluctuation brought by raw materials (such as clay).Sunlets recommends the following advanced methods:
Never put solid decoagulant directly. An aqueous solution with a specific concentration (usually 10%-20%) must be prepared in advance and added precisely by a metering pump to avoid "burning" due to excessive local charge density of the slurry ".
During the addition of the coagulant, the slurry storage tank should be kept under high shear agitation.According to the data of, high shear mixing can shorten the coagulation equilibrium time by about 40%.
Sunlets' Original Insight: Dynamic Feedback between Decoagulant and High Pressure Forming Pressure
During the operation of high pressure grouting equipment, we found a unique phenomenon: the amount of decoagulant added must be dynamically adjusted according to the ambient temperature on that day.
Non-linear relationship between temperature and viscosity: When the ambient temperature increases by 5°C, the viscosity of the slurry will decrease. At this time, if the original dosage of the decoagulant is maintained, the slurry will be excessively dispersed, and an excessively dense filter cake will be formed under high pressure (1.2 MPa), which will reduce the drainage rate.We integrated an online viscosity sensor in the equipment control system,The feeding strategy of the decoagulant is dynamically adjusted by feedback data to ensure that the wall-forming rate is always maintained in the optimal range.