Preparation process of high-performance self-leveling mortar

Abstract

The invention relates to the technical field of self-leveling mortar, in particular to a preparation process of high-performance self-leveling mortar, which comprises the following steps: drying and dewatering a desulfurized gypsum raw material by adopting a paddle dryer, analyzing the drying effect of the desulfurized gypsum raw material during the period, and dynamically adjusting the rotating speed of a main shaft of the paddle dryer to obtain dried desulfurized gypsum. The preparation method comprises the following steps: mixing desulfurized gypsum with an activator after calcining and cooling to obtain desulfurized gypsum gelling powder, fully stirring the desulfurized gypsum gelling powder with sulphoaluminate cement and Portland cement, and adding powder aggregate and a doping material; and continuously adding the functional additive to obtain a self-leveling mortar dry material, and adding water for mixing and stirring to obtain the self-leveling mortar. The invention aims to dynamically adjust the rotating speed of the main shaft of the paddle dryer, reduce bonding accumulation and improve drying uniformity and product quality.

Description

Technical Field

[0001] This application relates to the technical field of self-leveling mortar, and specifically relates to a preparation process for high-performance self-leveling mortar. Background Art

[0002] Currently, traditional cement dry-mixed mortar is still the main material for floor leveling, consuming a large amount of cement and construction sand and gravel. However, ordinary cement dry-mixed mortar has weak leveling ability, is not only time-consuming and laborious, but also has a high cost. In addition, cement mortar has problems such as large shrinkage, easy hollowing and cracking, and is not suitable for underfloor heating leveling. Quality problems such as hollowing and abnormal noise are likely to occur in the laid wooden floors, tiles, etc. Under the trend of strengthening the comprehensive utilization of solid waste and promoting the development of low-carbon and green building materials, gypsum self-leveling, also known as gypsum-based self-leveling mortar, is a newer, more environmentally friendly, and more economical product to replace cement mortar. It has the strength of cement and is healthier, more environmentally friendly, and more durable than cement.

[0003] Desulfurized gypsum usually contains more than 13% of surface free water, which is easy to bond and affects the fluidity of desulfurized gypsum, making it difficult to calcine stable and high-quality hemihydrate desulfurized gypsum. Therefore, drying and water removal in the preparation process of self-leveling mortar is a key link, and indirect heating needs to be carried out through a paddle dryer to remove surface free water. The desulfurized gypsum material has high viscosity, and there is a risk of material adhesion and caking during the drying and water removal process, easily forming local overheating and adhesive accumulation phenomena, reducing the purity of the dihydrate phase of desulfurized gypsum, and ultimately reducing the product stability and comprehensive performance of self-leveling mortar. Summary of the Invention

[0004] In view of the above, it is necessary to provide a preparation process for high-performance self-leveling mortar to solve the above problems.

[0005] An embodiment of this application provides a preparation process for high-performance self-leveling mortar, and the process includes:

[0006] Using a paddle dryer to dry and remove water from the desulfurized gypsum raw material. During this period, analyze the drying effect of the desulfurized gypsum raw material, dynamically adjust the main shaft speed of the paddle dryer, and obtain the dried desulfurized gypsum. After calcination and cooling, mix it with an activator to obtain desulfurized gypsum cementitious powder;

[0007] After fully stirring the desulfurized gypsum cementitious powder, sulphoaluminate cement, and Portland cement, add powder aggregate and dopant; continue to add a functional admixture to obtain self-leveling mortar dry material, and add water and mix and stir to obtain self-leveling mortar;

[0008] The specific operation of dynamically adjusting the main shaft speed of the paddle dryer is:

[0009] Compare the moisture content and temperature of the desulfurized gypsum raw material with those under standard conditions to determine the drying product deviation value at each moment; evenly divide the preset regulation period to obtain the scale period; confirm the material bonding and stacking strength of the corresponding regulation period through the change characteristics of the dispersion degree of all drying product deviation values within each scale period in the corresponding regulation period, and combine the distribution characteristics of all the drying product deviation values within each regulation period in each scale period to obtain the drying speed enhancement coefficient for each regulation period; analyze the deviation between the thickness value of the desulfurized gypsum raw material at the feed inlet and the standard thickness, and combine the drying speed enhancement coefficient to obtain the main shaft speed adjustment value for each regulation period.

[0010] Among them, the steam pressure during drying and water removal is 0.1 - 0.4 MPa, the drying temperature range is 50 - 75 °C, and the duration is 1 - 2 h.

[0011] Among them, the calcination temperature is 150 - 180 °C, and the calcination duration is 1.5 - 2.5 h.

[0012] Among them, the specific operation of mixing with the activator after cooling is to add the activator after cooling to below 100 °C, and the activator is at least one of Na2SO4, K2SO4, CuSO4, or Al2(SO4)3.

[0013] Among them, the powder aggregate is 30 - 100 parts of mineral powder, 20 - 50 parts of fly ash, and 30 - 60 parts of slag; the doping material is 100 - 200 parts of carbonized steel slag and 80 - 150 parts of blast furnace slag.

[0014] Among them, the functional admixture is 1 - 5 parts of water reducer, 0.5 - 3 parts of retarder, 3 - 10 parts of defoamer, 0.5 - 2 parts of water retention agent, 4 - 15 parts of redispersible latex powder, and 0.5 - 2 parts of activator.

[0015] Among them, the determination of the drying product deviation value at each moment includes:

[0016] Record the ratio between the moisture content of the desulfurized gypsum material at each moment and the standard moisture content as the moisture content deviation value; correspondingly, obtain the temperature deviation value based on the temperature data of the desulfurized gypsum material;

[0017] Add the difference between 1 and the moisture content deviation value to the temperature deviation value to obtain the drying product deviation value at each moment.

[0018] Among them, the confirmation of the material bonding and stacking strength of the corresponding regulation period is specifically:

[0019] Take the dispersion degree of all drying product deviation values at all moments within each scale period as the drying product fluctuation characteristic value of each scale period;

[0020] The slope obtained by linearly fitting the drying product fluctuation characteristic values of all scale cycles in each regulation cycle is used as the instability aggravation coefficient;

[0021] Calculate the mean value of the drying product fluctuation characteristic values of all scale cycles within each regulation cycle, denoted as the first mean value; the result of positively fusing the first mean value with the instability aggravation coefficient is used as the material adhesion and accumulation strength of each regulation cycle.

[0022] Among them, the specific method for obtaining the drying speed enhancement coefficient of each regulation cycle is as follows:

[0023] Calculate the mean value of the drying product deviation values corresponding to all sampling moments within each scale cycle of the regulation cycle, as the adhesion overheating evaluation value of each scale cycle within the regulation cycle;

[0024] Calculate the mean value of the adhesion overheating evaluation values of all scale cycles within the regulation cycle, denoted as the second mean value; calculate the normalized value of the product of the second mean value and the material adhesion and accumulation strength, as the drying speed enhancement coefficient of the regulation cycle.

[0025] Among them, the specific process for obtaining the main shaft speed adjustment value of each regulation cycle is as follows:

[0026] Based on the preset drying duration, obtain the ratio of the thickness value of the desulfurized gypsum material at each moment within a period of time before the current regulation cycle to the preset standard thickness value, and take the average to obtain the feed deviation amount of the current regulation cycle;

[0027] Obtain the main shaft speed adjustment value F of each regulation cycle ′ : F ′ =[(R×ω)+α]×F; where F is the actual main shaft speed of the paddle dryer within each regulation cycle; α is the preset tuning factor; R represents the feed deviation amount of each regulation cycle; ω represents the drying speed enhancement coefficient of each regulation cycle.

[0028] This application has at least the following beneficial effects:

[0029] 1. By calculating the material adhesion and accumulation strength, this application avoids the difficulty of realizing optimized control of drying water removal due to the drying product deviation value and the adhesion overheating evaluation value, improves the accuracy of evaluating the local overheating and adhesion and accumulation phenomena of the desulfurized gypsum material, and enhances the drying water removal control effect.

[0030] 2. This application takes into account the drying feed quantity of desulfurized gypsum in the next regulation cycle, avoids the mismatch between the adjusted value of the main shaft speed and the actual working conditions in the next regulation cycle, improves the drying control accuracy, and minimizes the possibility of wall sticking and material blockage, reduces local overheating and adhesive accumulation phenomena, enables the desulfurized gypsum material to be more evenly distributed during the drying process, improves the purity of the dihydrate phase of desulfurized gypsum, and ensures the product stability and comprehensive performance of the self-leveling mortar.

[0031] 3. The self-leveling mortar prepared by this application through a ternary cementitious system mainly uses low-carbon cementitious materials such as gypsum and mineral powder. By utilizing the mutual excitation reaction of industrial by-products such as desulfurized gypsum, mineral powder, slag, and fly ash as cementitious materials, it greatly reduces the cement dosage and carbon emissions, and improves the utilization rate of solid waste, turning waste into treasure, and has better social benefits such as energy conservation, carbon reduction, resource conservation, and sustainable development.

[0032] 4. The flatness of the entire ground leveled by the self-leveling mortar of this application can reach within 2 mm, and there are no shrinkage and hollowing problems in the later stage. The ground is formed in one time without secondary leveling, and wooden floors, large thin tiles such as large rock slabs can be directly laid, which not only ensures the decoration quality, but also saves time and effort, shortens the construction period, and is more economical, solving the difficult and painful problems of ground leveling in current decoration projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a flow chart of a preparation process for a high-performance self-leveling mortar provided by this application;

[0034] Figure 2 is a specific operation flow chart for dynamically adjusting the main shaft speed of the paddle dryer provided by this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In the description of the embodiments of this application, words such as "exemplary", "or", "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary", "or", "for example" aims to present relevant concepts in a specific manner.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0037] It should be noted that the terms "first" and "second" in this application and its accompanying drawings are used to distinguish similar objects, rather than to describe a specific order or sequence. The methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the methods. Without departing from the scope of protection of this application, the execution order of multiple steps can be interchanged with each other, and some steps can also be deleted.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0039] Example 1

[0040] The composition of a high-performance self-leveling mortar in Example 1 of this application includes: 200 parts of desulfurized gypsum, 40 parts of sulfoaluminate cement, 20 parts of portland cement, 30 parts of mineral powder, 20 parts of fly ash, 30 parts of slag, 100 parts of carbonized steel slag, 80 parts of blast furnace slag, 0.5 part of activator, 1 part of water reducer, 0.5 part of retarder, 3 parts of defoamer, 0.5 part of water retention agent, 4 parts of redispersible latex powder and 0.5 part of activator.

[0041] A preparation process of a high-performance self-leveling mortar, which is applied to the technical field of self-leveling mortar, with reference to the attached Figure 1 , the process includes:

[0042] S1. Prepare desulfurized gypsum cementitious powder:

[0043] a. Raw material transportation. Use a loader to transport desulfurized gypsum raw materials from the raw material yard to the wet material bin for storage. An auxiliary vibrator is installed in the wet material bin to prevent wet materials from clogging, ensure the smooth outflow of raw materials, and transport the materials through the raw material conveyor belt. During the transportation of raw materials, iron impurities are removed by a magnetic separator to ensure the purity of the raw materials and supply desulfurized gypsum raw materials to the paddle dryer.

[0044] b. Drying and water removal. The moisture content of desulfurized gypsum raw materials is relatively high. A paddle dryer using steam as the heat source is used to dry the high-moisture-content desulfurized gypsum raw materials through indirect heat transfer. The raw materials slowly move from the feeding end to the discharging end in the paddle dryer to reduce the free water content in the desulfurized gypsum raw materials. In this embodiment, the steam pressure is 0.4 MPa, and the drying temperature range is 50 - 75 °C.

[0045] In order to overcome the deficiencies of the prior art, in the drying and water removal link of the self-leveling mortar preparation process, this application proposes a drying and water removal control method to solve the problems that the desulfurized gypsum material has high viscosity, there is a risk of material adhesion and caking during the drying and water removal process, it is easy to form local overheating and agglomeration accumulation phenomena, reduce the purity of the dihydrate phase of desulfurized gypsum, and ultimately reduce the product stability and comprehensive performance of the self-leveling mortar. Among them, the specific method of drying and water removal control is as follows:

[0046] b01: Collect the thickness of the desulfurized gypsum raw material at the feed inlet of the paddle dryer, and obtain the moisture content and temperature of the desulfurized gypsum raw material at the discharge outlet.

[0047] This application places a non-contact measuring instrument above the raw material conveyor belt at the feed inlet of the paddle dryer to obtain the feed thickness value of the desulfurized gypsum material entering the paddle dryer. Specifically, the measuring instrument can use a laser sensor to obtain the laser reflection data on the surface of the desulfurized gypsum material layer, calculate the vertical height difference of the desulfurized gypsum layer, which is the feed thickness value, and the sampling rate of the laser sensor is 10Hz.

[0048] This application places a non-contact measuring instrument above the conveyor belt at the discharge outlet of the paddle dryer to realize the synchronous measurement of the moisture content and surface temperature of the desulfurized gypsum material area. Specifically, a microwave moisture meter and an infrared thermometer can be integrated. Set the sampling interval of the measuring instruments at the feed inlet and discharge outlet of the paddle dryer to 1s. At the same time, in order to avoid the influence of frequent control of the paddle drying process parameters on the product quality, this application will use T as the regulation period of the paddle drying process parameters, that is, adjust the process parameters of the paddle dryer once every regulation period T. In this embodiment, the regulation period T is taken as 15min.

[0049] b02: Compare the differences in the moisture content and temperature of the desulfurized gypsum raw material with the standard situation to determine the drying product deviation value at each moment; evenly divide the preset regulation period to obtain a scale period; through the change characteristics of the dispersion degree of all drying product deviation values within each scale period in the corresponding regulation period, confirm the material adhesion and accumulation strength of the corresponding regulation period, and combine the distribution characteristics of all the drying product deviation values within each regulation period in each scale period to obtain the drying speed enhancement coefficient of each regulation period.

[0050] The surface free water moisture content of desulfurized gypsum is generally above 13%, which is easy to adhere and affect the fluidity of desulfurized gypsum, and it is difficult to calcine stable and high-quality hemihydrate desulfurized gypsum. This application adopts a two-step process of drying + calcination to improve the quality stability of the self-leveling mortar product.

[0051] The paddle dryer uses steam as the heating medium. The heating medium flows in the jacket of the paddle dryer housing and the inner cavity of the paddle shaft, and the rotating paddles are used to turn the desulfurized gypsum, dynamically adjusting the heating interface of the desulfurized gypsum, and indirectly drying and dewatering the desulfurized gypsum material. Due to the high viscosity of the desulfurized gypsum raw material, during the drying and dewatering process, the desulfurized gypsum raw material inside the paddle dryer is prone to adhesion, which easily causes local adhesion and overheating of the paddle dryer. Finally, the surface temperature of the partially desulfurized gypsum after drying and dewatering is high and the moisture content is low.

[0052] In this application, at any sampling moment within the regulation period T, the moisture content value w and the temperature value h of the desulfurized gypsum material at the outlet of the paddle dryer are obtained. The standard temperature value H and the standard moisture content W for the desulfurized gypsum material after drying and dewatering are set. The ratio of the temperature value h to the standard temperature value H at any moment is calculated as the temperature deviation value Δh. Similarly, the moisture content deviation value Δw can be obtained.

[0053] In this embodiment, in order to avoid the phenomenon that when the temperature approaches or exceeds 75°C, 0.5 crystal waters are locally removed from the calcium sulfate dihydrate (CaSO4·2H2O) in the desulfurized gypsum, generating β-type hemihydrate gypsum, resulting in the mixing of the desulfurized gypsum after drying and dewatering, the standard temperature value H is lower than 75°C. In this embodiment, the standard temperature value H is taken as 60°C.

[0054] In one embodiment, desulfurized gypsum with a low moisture content is more likely to obtain a self-leveling slurry with stable quality and excellent performance. However, too low a moisture content consumes more energy. In this embodiment, the standard moisture content value W is taken as 2%.

[0055] This application calculates the drying product deviation value P of the desulfurized gypsum material at the outlet of the paddle dryer at any sampling moment through the formula P = Δh+(1 - Δw). The higher the surface temperature and the lower the moisture content of the partially desulfurized gypsum after drying and dewatering, it indicates that at the sampling moment, the paddle dryer is more likely to have formed a local adhesion and overheating phenomenon, and the desulfurized gypsum at the corresponding outlet at the current sampling moment is more likely to be the desulfurized gypsum peeled off from the locally adhered and overheated area.

[0056] The regulation period T is evenly divided into N scale periods t, where T = N×t. In this embodiment, the scale period t is taken as 1 min. Calculate the mean value of the drying product deviation values corresponding to all sampling moments within each scale period of the regulation period as the adhesion and overheating evaluation value for each scale period within the regulation period, which is used to reduce the measurement accuracy error of the desulfurized gypsum at the outlet and reflect the possibility of the existence of local adhesion and overheating phenomenon of the paddle dryer within the scale period.

[0057] In the drying and water removal process of the self-leveling mortar preparation process, the thin-layer desulfurized gypsum material with local bonding overheating phenomenon initially formed may be covered by new desulfurized gypsum during the subsequent feeding process, and the bonding material accumulation is aggravated in the local overheating area. Due to the bonding material accumulation, it is difficult for the inner-layer desulfurized gypsum of the bonding accumulation to fall off, and it is difficult to realize the optimized control of drying and water removal through the drying product deviation value and the bonding overheating evaluation value, and there is a lack of countermeasures for the bonding accumulation of desulfurized gypsum material.

[0058] The desulfurized gypsum material accumulates and adheres to the paddle blades, causing fluctuations in the heat transfer efficiency of the paddle dryer, significantly affecting the drying effect of the paddle dryer, and easily resulting in poor stability and high quality volatility of the desulfurized gypsum drying product. In this application, the drying product fluctuation characteristic value of each scale period within the regulation period during the drying and water removal process is calculated to reflect the stability of the desulfurized gypsum drying product quality. Specifically, the drying product fluctuation characteristic value can be calculated by calculating the information entropy, standard deviation, and variance of the corresponding drying product deviation values at all sampling moments of the corresponding scale period. In this embodiment, the variance is used for calculation.

[0059] As the drying and water removal process of the desulfurized gypsum progresses, if the desulfurized gypsum accumulated and adhered to the paddle blades is not processed in time, it is easy to exacerbate the instability of the desulfurized gypsum drying product. In this application, the instability exacerbation coefficient of each regulation period during the drying and water removal process is calculated to reflect the exacerbation degree of the desulfurized gypsum accumulated and adhered to the paddle blades on the instability of the drying product quality. Specifically, in this embodiment, the drying product fluctuation characteristic values of all scale periods within each regulation period are arranged in ascending order of time to form a characteristic value sequence, and the least squares method is used for linear fitting to obtain the slope of the fitting line of the characteristic value sequence as the instability exacerbation coefficient; it should be noted that the least squares method is a well-known existing technology, and this application will not elaborate on it.

[0060] Furthermore, obtain the material bonding and accumulation strength of each regulation period during the drying and water removal process: calculate the mean value of the drying product fluctuation characteristic values of all scale periods within each regulation period, denoted as the first mean value; the result of the positive fusion of the first mean value and the instability exacerbation coefficient is used as the material bonding and accumulation strength of each regulation period. In this embodiment, the positive fusion of multiple variables is calculated by multiplication.

[0061] It should be understood that the worse the stability of the desulfurized gypsum drying product quality, and the higher the exacerbation degree of the instability of the drying product quality, the more likely there is desulfurized gypsum material accumulation and adhesion on the paddle blades within the regulation period, and the more necessary it is to optimize the regulation of the paddle dryer by means of the drying and water removal control method, reduce the desulfurized gypsum material accumulation and adhesion, make the desulfurized gypsum material more evenly distributed during the drying process, and ultimately improve the quality stability and performance of the self-leveling mortar.

[0062] In the drying and water removal process of the self-leveling mortar preparation process, the main shaft speed of the paddle dryer is directly related to the drying time of desulfurized gypsum. Increasing the main shaft speed can enhance the stirring effect of the paddle on the desulfurized gypsum material, make the desulfurized gypsum material more evenly distributed during the drying process, reduce the possibility of wall sticking and blockage, and reduce local overheating and adhesive accumulation phenomena.

[0063] This application obtains the drying speed enhancement coefficient for this regulation cycle through the overheating adhesion evaluation value and the material adhesion accumulation strength. The larger the drying speed enhancement coefficient, the more obvious the local overheating and adhesive accumulation phenomena are, the greater the impact on the quality of the desulfurized gypsum drying product, and the more the main shaft speed of the paddle dryer should be increased. Specifically, in this embodiment, the average value of the overheating adhesion evaluation values of all scale cycles within the regulation cycle is calculated and denoted as the second average value; the normalized value of the product of the second average value and the material adhesion accumulation strength is used as the drying speed enhancement coefficient for the regulation cycle. The normalization method adopted in this embodiment is the maximum-minimum normalization method.

[0064] b03: Analyze the deviation between the thickness value of the desulfurized gypsum raw material at the feed inlet and the standard thickness, and combine the drying speed enhancement coefficient to obtain the main shaft speed adjustment value for each regulation cycle.

[0065] In the drying and water removal process of the self-leveling mortar preparation process, a larger desulfurized gypsum feed rate is more likely to cause adhesion phenomena and also requires a higher main shaft speed to promote the drying uniformity of the desulfurized gypsum material. The drying and dehydration time is taken as 1 h in one implementation case. The current regulation cycle is (t1, t2), where t1 + T = t2. This application obtains the feed thickness value sequence within (t1 - 1, t2 - 1 + T) and calculates the average value of the ratio of each feed thickness value to the standard thickness value as the feed deviation amount for the current regulation cycle, denoted as R. Here, T is the time length of the regulation cycle. The purpose of calculating t2 - 1 + T is to consider the feed deviation amount of the next regulation cycle and improve the drying control accuracy. Here, the standard thickness value is taken as 5 cm in this embodiment, and the implementer can adjust it according to specific circumstances.

[0066] This application obtains the main shaft speed adjustment value F for each regulation cycle through the following formula ′ : F ′ = [(R × ω) + α] × F; in the formula, F is the actual main shaft speed of the paddle dryer within each regulation cycle, which can be specifically obtained through a speed sensor. The main shaft speed adjustment value F ′The spindle speed calculated for the next regulation cycle for each regulation cycle, α is a tuning parameter factor, which takes a value of 0.6 in this embodiment and is used to adjust the spindle speed according to the value of (R×ω), and the value range is [0.4, 0.6], and the implementer can set it according to the actual situation; R represents the feed deviation amount for each regulation cycle; ω represents the drying speed enhancement coefficient for each regulation cycle. When the local overheating and agglomeration phenomena are more significant within the current regulation cycle, it is more necessary for the paddle dryer to increase the spindle speed to enhance the stirring effect of the paddles on the desulfurized gypsum material, F ′ is larger; when the feed rate of desulfurized gypsum is larger, the agglomeration phenomenon is more likely to occur, and a higher spindle speed is more necessary to promote the drying uniformity of the desulfurized gypsum material, F ′ is larger.

[0067] Adjust the calculated spindle speed adjustment value F in the industrial control system ′ as the spindle speed for the next regulation cycle, obtain the actual speed through a speed sensor, and use a PID controller to adjust the spindle speed of the paddle dryer to achieve the drying and water removal control of desulfurized gypsum. This application tries to reduce the local overheating and agglomeration phenomena during the drying and water removal process, and avoid premature internal dehydration of some desulfurized gypsum to generate hemihydrate desulfurized gypsum, resulting in a mixed phase composition of the dried desulfurized gypsum material. Different from pure dihydrate gypsum after entering the calcination kiln, it is easy to cause inaccuracies in the control of calcination temperature and time, and a multi-phase mixture appears in the final product, reducing the performance and mechanical strength of the gypsum cement. Among them, the initial spindle speed of the paddle dryer is taken as 5 rpm in this embodiment.

[0068] Among them, the specific operation flow chart for dynamically adjusting the spindle speed of the paddle dryer is as Figure 2 shown.

[0069] Using the drying and water removal control method, dynamically regulate the spindle speed of the paddle dryer to reduce the local overheating and agglomeration phenomena during the drying and water removal process, avoid premature internal dehydration of some desulfurized gypsum, and ensure product quality.

[0070] c: Gypsum calcination. The dried desulfurized gypsum is transported to a steam tube calcination kiln for calcination to remove the internal crystal water in the desulfurized gypsum (CaSO4·2H2O) to form hemihydrate gypsum (CaSO4·1 / 2H2O). By using a slow calcination method, the crystal structure of the gypsum can be better controlled, the product performance can be improved, and the requirements for strength and performance of the gypsum-based self-leveling material can be met. Among them, the calcination temperature is 150 °C and the calcination time is 1.5 h.

[0071] d: Cooling.

[0072] The calcined high-temperature gypsum is indirectly cooled to below 80°C by cold air to prevent secondary dehydration. It is then mixed with 0.5 to 2 parts of an activator and ground to obtain a desulfurized gypsum gelling powder. The activator is sulfate, which is Na2SO4 and Al2(SO4)3 in this embodiment. The activator can promote the integrity of the hydration product and improve the structural density.

[0073] S2. Preparation of gypsum-based cementitious materials:

[0074] The ternary system formed by sulphoaluminate cement, silicate cement and gypsum, whose main reaction product, ettringite, has the characteristics of fast setting speed, high water retention capacity and shrinkage compensation. Under normal temperature conditions, the obtained desulfurized gypsum cementitious powder, 40 parts of sulphoaluminate cement and 20 parts of silicate cement are put into a high-speed mixer and fully stirred to form a uniform ternary composite cementitious system.

[0075] S3. Preparation of mixed powder aggregate and admixture:

[0076] In a high-speed mixer of gypsum-based cementitious materials, powder aggregate and doping materials are added. The powder aggregate is 30 parts of mineral powder, 20 parts of fly ash, and 30 parts of slag. The doping materials are 100 parts of carbonized steel slag and 80 parts of blast furnace slag.

[0077] Among them, the addition of mineral powder and fly ash improves the fluidity of high gypsum-based self-leveling materials, and slag and fly ash have light specific gravity and are more active in gypsum and alkaline environments, thus having higher strength. Among them, carbonized steel slag is preferably steel slag that has been carbonized for 24 hours, which enhances the late compression and flexural strength of low-carbon self-leveling mortar. Slag, and blast furnace slag as an admixture of mortar and gypsum in an alkaline environment have higher activity and generate new hydration products, thereby making the material stronger.

[0078] S4, mixed functional admixtures:

[0079] After mixing the powder aggregate and admixture, functional admixtures are added into a high-speed mixer to obtain self-leveling mortar dry material. The functional admixtures are 1 part of water reducer, 0.5 part of retarder, 3 parts of defoamer, 0.5 part of water retaining agent, 4 parts of redispersible latex powder and 0.5 part of activator.

[0080] Among them, the activator is triethanolamine, which makes gypsum react with slag, fly ash and furnace slag faster and more fully, thereby enhancing the early and later strength of the self-leveling mortar.

[0081] Among them, the water reducer adopts a polycarboxylic acid water reducer to improve the fluidity of the slurry, and the retarder adopts a protein retarder to prolong the setting time. Since the polycarboxylic acid water reducer will reduce the strength of the self-leveling mortar and the protein retarder will cause segregation and water seepage in the self-leveling mortar, this application adds a water-retaining agent and a redispersible latex powder to enhance the anti-cracking performance of the self-leveling mortar and improve the flexural strength of the hardened body.

[0082] S5. Preparation of self-leveling mortar:

[0083] According to the amount of dry material of self-leveling mortar, add water in a ratio of 2:1 and stir thoroughly to complete the preparation of self-leveling mortar.

[0084] Example 2

[0085] The ingredients of a high-performance self-leveling mortar in Example 2 of the present application include: 800 parts of desulfurized gypsum, 100 parts of sulphoaluminate cement, 70 parts of silicate cement, 100 parts of mineral powder, 50 parts of fly ash, 60 parts of slag, 200 parts of carbonized steel slag, 150 parts of blast furnace slag, 2 parts of activator, 5 parts of water reducer, 3 parts of retarder, 10 parts of defoamer, 2 parts of water retaining agent, 15 parts of redispersible latex powder and 2 activators.

[0086] A preparation process of high-performance self-leveling mortar, applied in the field of self-leveling mortar technology, refer to the attached Figure 1 , the process comprises:

[0087] S1: The same steps as S1 of Example 1 are used to transport the desulfurized gypsum raw material, dry and dehydrate, calcine the gypsum, and cool it. The steam pressure during drying and dehydration is 0.1 MPa, the drying temperature range is 50-60°C, the standard temperature value is 55°C, and the duration is 2 hours; the calcination temperature during gypsum calcination is 180°C, the calcination time is 2 hours; the cooling temperature is 80°C, and the activators used are K2SO4 and CuSO4.

[0088] S2-S5: The same steps as S2-S5 of Example 1 were adopted to prepare self-leveling mortar.

[0089] Example 3

[0090] The ingredients of a high-performance self-leveling mortar in Example 3 of the present application include: 600 parts of desulfurized gypsum, 60 parts of sulphoaluminate cement, 70 parts of silicate cement, 80 parts of mineral powder, 20 parts of fly ash, 60 parts of slag, 160 parts of carbonized steel slag, 100 parts of blast furnace slag, 0.5 parts of activator, 3 parts of water reducer, 1.5 parts of retarder, 7 parts of defoamer, 1 part of water retaining agent, 9 parts of redispersible latex powder and 1 activator.

[0091] A preparation process of high-performance self-leveling mortar, applied in the field of self-leveling mortar technology, refer to the attachedFigure 1 , the process includes:

[0092] S1: The desulfurized gypsum raw material is transported, dried and dewatered, calcined, and cooled using the same steps as S1 in Example 1. Among them, the steam pressure during drying and dewatering is 0.1 MPa, the drying temperature range is 55 - 70 °C, the standard temperature value is 60 °C, and the duration is 1.5 h; the calcination temperature during gypsum calcination is 170 °C, and the calcination time is 2.5 h; the cooling temperature is 90 °C, and the activators used are Al2(SO4)3 and K2SO4.

[0093] S2 - S5: All use the same steps as S2 - S5 in Example 1 to prepare self - leveling mortar.

[0094] This application will use the drying and dewatering control method proposed in this application as an example, and not use the drying and dewatering control method proposed in this application as a comparative example. Referring to "Methods for Chemical Analysis of Gypsum" (GB / T 5484 - 2024) and "Methods for Phase Composition Analysis of Building Gypsum" (GB / T 36141 - 2018), the moisture content and dihydrate phase purity of the desulfurized gypsum after drying are tested. Referring to "Determination of Physical Properties of Building Gypsum Paste" (GB / T 17669.4 - 1999) and "Determination of Mechanical Properties of Building Gypsum" (GB / T 17669.3 - 1999), the fluidity, flexural strength, and compressive strength of the self - leveling mortar are determined.

[0095] Table 1 shows the product quality stability of the desulfurized gypsum after drying:

[0096]

[0097]

[0098] Table 2 shows the performance of the self - leveling mortar

[0099]

[0100] The drying and dewatering control method in this application can significantly reduce the moisture content of the desulfurized gypsum after drying, and make the fluctuation of the product moisture content smaller, the quality stability higher, and improve the dihydrate phase purity of the desulfurized gypsum. Furthermore, it can improve the performance such as the fluidity, flexural strength, and compressive strength of the self - leveling mortar using it as a raw material. In practical applications, the self - leveling mortar produced from desulfurized gypsum using the method of this application has better construction performance and stronger mechanical properties, can better meet the quality requirements of building floor self - leveling construction, and has significant performance advantages and practical application value.

[0101] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of code that contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions noted in the block may occur in a different order than noted in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved. Each block in the block diagram and / or flowchart, as well as combinations of blocks in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0102] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A preparation process of a high-performance self-leveling mortar, characterized in that, The process includes: Using a paddle dryer to dry and remove water from the desulfurized gypsum raw material. During this process, analyze the drying effect of the desulfurized gypsum raw material, dynamically adjust the main shaft speed of the paddle dryer, and obtain the dried desulfurized gypsum. After calcination and cooling, mix it with an activator to obtain a desulfurized gypsum cementitious powder; After fully stirring the desulfurized gypsum cementitious powder, sulfoaluminate cement, and Portland cement, add powder aggregate and dopant; continue to add functional admixtures to obtain a self-leveling mortar dry material, add water and mix and stir to obtain a self-leveling mortar; The specific operation of dynamically adjusting the main shaft speed of the paddle dryer is as follows: Compare the differences in the moisture content and temperature of the desulfurized gypsum raw material with those under standard conditions to determine the drying product deviation value at each moment; evenly divide the preset regulation period to obtain a scale period; through the variation characteristics of the dispersion degree of all drying product deviation values within each scale period in the corresponding regulation period, confirm the material bonding and stacking strength of the corresponding regulation period. Combine the distribution characteristics of all the drying product deviation values within each regulation period in each scale period to obtain the drying speed enhancement coefficient for each regulation period; analyze the deviation between the thickness value of the desulfurized gypsum raw material at the feed inlet and the standard thickness, and combine the drying speed enhancement coefficient to obtain the main shaft speed adjustment value for each regulation period.

2. The preparation process of a high-performance self-leveling mortar as described in claim 1, characterized in that, In the drying and water removal process, the steam pressure is 0.1 - 0.4 MPa, the drying temperature range is 50 - 75 °C, and the duration is 1 - 2 h.

3. The preparation process of a high-performance self-leveling mortar as described in claim 1, characterized in that, The temperature of the calcination is 150 - 180 °C, and the calcination duration is 1.5 - 2.5 h.

4. The preparation process of a high-performance self-leveling mortar as described in claim 1, characterized in that, The specific operation of mixing with the activator after cooling is to add the activator after cooling to below 100 °C, and the activator is at least one of Na2SO4, K2SO4, CuSO4, or Al2(SO4)3.

5. The preparation process of a high-performance self-leveling mortar as claimed in claim 1, characterized in that, The powder aggregate is 30 - 100 parts of mineral powder, 20 - 50 parts of fly ash, and 30 - 60 parts of slag; the dopant is 100 - 200 parts of carbonized steel slag and 80 - 150 parts of blast furnace slag.

6. The preparation process of a high-performance self-leveling mortar as described in claim 1, characterized in that, The functional admixtures are 1 - 5 parts of water reducer, 0.5 - 3 parts of retarder, 3 - 10 parts of defoamer, 0.5 - 2 parts of water retention agent, 4 - 15 parts of redispersible latex powder, and 0.5 - 2 parts of activator.

7. The preparation process of a high-performance self-leveling mortar as described in claim 1, characterized in that, The determination of the drying product deviation value at each moment includes: Record the ratio between the moisture content of the desulfurized gypsum material at each moment and the standard moisture content as the moisture content deviation value; correspondingly, based on the temperature data of the desulfurized gypsum material, obtain the temperature deviation value; Add the difference between 1 and the moisture content deviation value to the temperature deviation value to obtain the drying product deviation value at each moment.

8. The preparation process of a high-performance self-leveling mortar according to claim 1, characterized in that, The confirmation of the material bonding and stacking strength of the corresponding regulation period is specifically: Take the dispersion degree of all drying product deviation values at all moments within each scale period as the drying product fluctuation characteristic value of each scale period; Take the slope of the linear fitting of all drying product fluctuation characteristic values of all scale periods within each regulation period as the instability exacerbation coefficient; Calculate the mean value of all drying product fluctuation characteristic values of all scale periods within each regulation period, denoted as the first mean value; The result of positively fusing the first mean value with the coefficient of increasing instability is used as the material bonding and accumulation strength of each control cycle.

9. The preparation process of a high-performance self-leveling mortar according to claim 1, characterized in that, The specific method for obtaining the drying speed enhancement coefficient of each control cycle is as follows: Calculate the mean value of the drying product deviation values corresponding to all sampling moments within each scale cycle of the control cycle as the bonding overheating evaluation value of each scale cycle within the control cycle; Denote the mean value of the bonding overheating evaluation values of all scale cycles within the control cycle as the second mean value; Calculate the normalized value of the product of the second mean value and the material bonding and accumulation strength as the drying speed enhancement coefficient of the control cycle.

10. The preparation process of a high-performance self-leveling mortar according to claim 1, characterized in that, The specific process for obtaining the main shaft speed adjustment value of each control cycle is as follows: Based on the preset drying duration, obtain the ratio of the thickness value of the desulfurized gypsum material at each moment within a period of time before the current control cycle to the preset standard thickness value, and calculate the average to obtain the feed deviation amount of the current control cycle; Obtain the spindle speed adjustment value F for each regulation cycle ′ : F ′ = [(R × ω) + α] × F; where F is the actual spindle speed of the paddle dryer within each regulation cycle; α is a preset parameter adjustment factor; R represents the feed deviation amount for each regulation cycle ω represents the drying speed enhancement coefficient of each control cycle.

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