Cement Grinding Aids Research Articles

Study on structure-performance relationship and action mechanism of organic chemicals in cement grinding aids

Grinding aids (GAs) are an important addtive in the cement production process. However, the relationship between the molecular structure of GAs and its grinding efficiency has not been clearly revealed. In this study, the influence of GAs with different structures, including glycols and alkanolamines, on the grinding efficiency of pure clinker was systematically investigated. The working mechanism from their adsorption and dispersion configurations on tricalcium silicate (C3S) surface was investigated by first-principles method. As the structural parameters of GAs, number of polar groups is found to affect the grinding efficiency of cement clinker. The grinding performance of alkanolamines is better than that of glycols at the same dosage, when the number of hydroxyl groups is the same. The tertiary alkanolamines are adsorbed through the double-ended hydroxyl group to form larger molecular projection areas than the glycols with single-ended hydroxyl group, thus resulting in higher dispersion efficiency. Further, with the growth of the number of methyl groups in the molecular structure of the tertiary alkanolamines, the thickness of the adsorbed molecular layer grows from 9.25 Å to 9.87 Å, and the ability to shield the electrostatic forces between cement particles is enhanced and result in a better grinding aid performance.

Effect of phosphate ester grinding aids on cement grinding and water-reducing performance

Phosphate ester polymers were prepared from phosphate ester monomers for the first time and their effects as cement grinding aids and water-reducing performance were studied. Fourier-transform infrared (FTIR) spectroscopy and tests for standard viscosity, setting time, mortar fluidity, mortar compressive strength were conducted. The results showed that hydroxyethyl dibutyl phosphate reduced the residues of 45 μm and 80 μm grinding sieves by 68.67% and 98.67%, respectively. Compared with triethanolamine, the grinding effect of hydroxyethyl dibutyl phosphate was not only better but also the optimal mixing amount was less (only 0.167%). For the same amount of grinder, the grinding time was shortened by 30% and, for the same grinding time, the grinding output was increased by at least 20%. The polymer grinding aids significantly improved the fluidity of cement paste (by 40.06%), meaning the water-reduction rate of cement mortar could reach over 20%. The experimental results show that, as a new generation of grinding aids, phosphate esters not only have a significant grinding effect but also have high molecular designability, which will significantly enrich the grinding aids market and effectively promote energy conservation and emissions reductions in the grinding process.

Cement grinding aid based on glycerol-waste antifreeze

Cement grinding aid based on glycerol-waste antifreeze

Influence of PCE-type GA on cement hydration performances

Modified polycarboxylate-type (PCE-type) grinding aid (GA) by grafting acylamino group and hydroxyl group into the backbone of PCE polymer was synthesized, and its possibility to be adopted as cement GA was estimated in this research. The grindability of PCE-type GA was measured in terms of grinding duration as well as particle size distribution, and the grindability of PCE-type GA was systematically compared with that of triethanolamine (TEA) and ordinary PCE-type superplasticizer. The cement hydration kinetics, the microstructure, and the physical–mechanical properties of ground cement samples in the function of PCE-based GA were analyzed. The results indicated that PCE-type GA was more effective in cement grinding process than TEA as well as PCE-type superplasticizer, exhibiting shortened grinding duration, optimized particle size distribution, and homogenized particle morphology. And cement ground by PCE-type GA was characterized with lower water demand, higher fluidity property, and increased mechanical strength, ascribed to the dispersion capability of PCE polymer as well as the unified cement particle size distribution. The application of PCE-type GA could slightly prolong the induction period of the ground cement, but gently enhance the hydration degree. Lower porosity and denser microstructure with higher density of cement hydration products uniformly distributing in the hardened matrix could be achieved with PCE-type GA adopted in the ground cement.

Analysis on Influencing Factors of Grinding Aid Effect of Cement Grinding Aids

In the cement industry, grinding aids can be used to improve the efficiency, promote the realization of the concept of energy saving and emission reduction, and reduce the production cost to a great extent. Cement grinding aid is a kind of material which can promote cement grinding, and it is an important part of energy-saving development of industry at present. It can not be ignored in improving cement technology. Based on this, this paper analyzes the influencing factors of grinding aid effect in cement grinding process.

Detection of alkanolamines in liquid cement grinding aids by HPLC coupled with evaporative light scattering detector.

Triethanolamine (TEA), triisopropanolamine (TIPA), diethanol isopropanolamine (DEIPA) are necessary cement additives, and knowing their contents is needed for quality control and also to understand final properties of the cement. Whether it is the production of grinding aids, technical research and development or application research all involve the detection of grinding aids. This work developed a simple analytical technique for the simultaneous analysis of these alkanolamines in liquid cement grinding aids using high-performance liquid chromatography (HPLC) combined with evaporative light scattering detection (ELSD). HPLC was conducted by an XBridge C18 column (with dimensions 4.6 × 250 mm and 5 µm particles) using methanol and 0.1% trichloroacetic acid as mobile elution phases. The ELSD sprayer and drift tube temperatures were 60 ºC and 90 ºC, respectively. HPLC-ELSD developed in this work demonstrated 1) high sensitivity with limits of detection for the three analytes are 0.15, 0.54, 1.04 µg/mL; 2) good linearity with correlation coefficients equal to 0.997–0.999 over the tested concentration range; 3) excellent repeatability with intra- and interday coefficient of variation (CV) below 2.71% and 4, satisfactory accuracy with recovery in the 95.5%–100.8% range. This novel method is a powerful, time- and costeffective tool for alkanolamine analyses and quality control.

Investigation on the optimal chemical structure of methacrylate ester based polycarboxylate superplasticizers to be used as cement grinding aid under laboratory conditions: Effect of anionicity, side chain length and dosage on grinding efficiency, mortar workability and strength development

Using polycarboxylate ether/ester (PCE) superplasticizers as cement grinding aid presents an interesting concept because the PCE could provide both grinding and fluidizing effect at the same time, thus achieving two benefits from the admixture. Here, a systematic study on the relationship between the molecular structure of ω-methoxy poly(ethylene glycol) methacrylate ester based PCE (MPEG-PCE) and their grinding efficiency was performed. A series of MPEG-PCEs with systematically modified compositions was employed and their impact on grinding efficiency was assessed. First of all, the PCE dosage required to achieve a certain fineness in a laboratory ball mill was determined. Then, the grinding efficiency of PCEs exhibiting different anionic charge density and side chain length was investigated. It was found that an optimal molar ratio of carboxylic acid : side chain exists, and that shorter side chains are more beneficial for grinding efficiency than longer ones. Furthermore, it was also found that intergrinding of MPEG-PCEs with clinker produces a cement with higher fluidity.

Review on Research of Cement Grinding Aids and Certain Problems

It can increase the cement fineness, improve cement production and improve comprehensive performance of cement significantly by adding grinding aids, and promote the use of grinding aids in reducing the energy consumption of cement production, with the adjustment of national economic growth and the elimination of backward production capacity. But the effect mechanism of the grinding aids is divided, and the grinding effect of the system is still need to be improved. In this paper, the development history of cement grinding aids is introduced, and the grinding aids are summarized systematically from the aspects of the grinding mechanism and present research situation at home and abroad. Study shows that current research only stay on the level of practice, not related to the in-depth research on the theory system and theoretical model, a set of grinding efficiency of composite grinding system and the corresponding scientific theory are need to establish.

The Effect on the Performance of Cement Grinding Aid Components

In this paper, By choosing four kinds of grinding aids better one-component, The grinding aid of cement grinding aids is determined by orthogonal optimization. By adding different inorganic reinforcing components, Developed a cement grinding aids.The result turns out, compared with blank sample, the adulteration of grinding aid leads compression strength of 3d, 7d and 28d respectively are improved 17.9%, 17.8% and 16.8%，cement fineness to reduce by 63.1% and specific surface area to increase about 10.6%. Meanwhile, cement particles ranging 3-32 μm is improved 11.3%, which optimizes the grain composition of cement and increases strength of cement. The experimental research to provide technical support for the future development of cement technology.

Goal and technology path of CO2 mitigation in China's cement industry: from the perspective of co-benefit

The concept of co-benefit, a negotiation topic in CO2 mitigation attracts worldwide attention including China in coping with climate change. Energy saving technologies as common measures for CO2 abatement, generally lead to co-benefits of local air pollution (LAP) because most LAP emissions are generated from combustion of carbonic fuels along with CO2. However, in the technological dimension, there are technologies that induce opposite effects on the co-benefit of CO2 and LAP in specific industry sectors. Precalcinating line and shaft kiln, two types of technologies adopted in clinker calcinating procedure in cement industry are examples: the former consume less energy but emit more dust and NOx than the later. As a result, the overall co-benefits of LAP reductions for cement industry are uncertain. This study consequently aims at assessing the overall co-benefit (although it may be a negative co-benefit) of CO2 mitigation policy on dust, NOx, SO2 emissions in China's cement industry aggregately by establishing bottom-up optimization model on the basis of all types of technologies which are called technology system in cement production. CO2 mitigation goal, as represented by reduction rate is regarded as constraint input into the model. In order to investigate the evolution of co-benefits and technology paths with the change of CO2 mitigation goal, hundreds of reduction rates are selected randomly between the range 0.5–10.5%. The lower bound 0.5% reveals CO2 emission reduction that can be reached for cement industry under existing political constraints and without any extra CO2 mitigation goal. The upper bound 10.5% is the greatest reduction rate under which the model could derive feasible solution. According to changes of technology penetration rates as CO2 goal tightens, we could evaluate the more cost-effective technologies from the perspective of co-benefit. They are vertical milling, precalcinating line with the scale of 7000–10,000 ton/day, roll-squeezer belonging to Main Production Technology (MPT), utilization of cement grinding aids, multi-channel coal burner belonging to Affiliated Energy-saving technology (AES), combination of bag-filter and electrostatic precipitator and ultra-low NOx burning technology belonging to Pollution Control Technology (PCT). With respect to the evolution of co-benefits on air pollutions, when the CO2 reduction rate is below 2.3%, co-benefit of dust and SO2 reduction exist while that of NOx does not; and when the rate is above 2.3%, co-benefits of all the three pollutants exist. A practically referable goal of CO2 mitigation rate of short/mid-term is approximately 5.5% in view of the following three considerations: a) co-benefits augment as CO2 reduction rate increases; b) total cost increases as the CO2 abatement goal becomes stricter; and c) the majority of emerging technologies normally cannot penetrate to 100% in cement production within a relatively short time.

Bioglycerol: a multifunctional aid for the construction industry

AbstractCrude bioglycerol from biodiesel and oleochemicals manufacturing is a multifunctional grinding aid and quality improver for the production of cement, capable of largely greening the concrete construction industry. This low‐cost renewable by‐product is now used by industry as a cement grinding aid as well as a curing and form‐release agent, replacing oil‐derived ingredients traditionally employed by the industry for over 50 years. Reviewing and providing new data on the usage and applications that have emerged in the last decade, we provide a unified picture answering most aspects required for a wider and fuller utilization of this versatile oleochemical in the ubiquitous concrete building industry. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd

Characteristics and mechanism of modified triethanolamine as cement grinding aids

Effects of modified triethanolamine as cement grinding aids on particles characteristics and mechanical property of cement were studied, and its reaction mechanism was analyzed by IR, Zeta potential, SEM, XRD and TG-DTA. The results show that the content of 3–32 μm particles for cement with 0.015% modified triethanolamine(M-TEA) is increased by 12.4%, and the compressive strengths of cement with 0.03% M-TEA are increased by 5.5 and 8.2 MPa at 3 and 28 days, respectively. And both the grinding and enhancement effects of M-TEA on cement are better than triethanolamine. The mechanism analysis shows that M-TEA not only has the amino and hydroxyl groups of TEA, but also has the ester, carbonyl, carboxyl groups which easily combine with metal ions of cement minerals, resulting in that M-TEA can promote surface adsorption and shield the unsaturated charges in the surface and crack section of particles, thus particles reunion is prevented and grinding efficiency is improved. Enhancement of M-TEA on cement mainly lies in that it can promote or induce hydration reaction of cement mineral with gypsum and water, which accelerates formation of hydration products, and then improves the structure and morphology of cement hydration products, thus the uniformity and compactness of product structure is increased.

Sustainable resource opportunity for cane molasses: use of cane molasses as a grinding aid in the production of Portland cement

Current methods used in China have failed to recycle cane molasses in an environmentally friendly way. Meanwhile, it is an urgent concern to find a cheap alternative to the present Portland cement grinding aids. However, the available literature has several limitations in properly evaluating the feasibility of using cane molasses as a Portland cement grinding aid. Therefore, the mixture of calcium sulfate and cement clinker is interground along with it, and mixture properties such as grindability, setting time, compressive strength, water absorption, compatibility with water reducing admixture, and hydration characteristics are systematically discussed and the mechanisms of these property variations are clarified. Besides, the economic, logistical, and environmental viability are also considered. The results show that cane molasses affects the cement grindability, setting time, compressive strength, water absorption, compatibility, hydration characteristics and microstructure, and these effects are related to its content. Moderate cane molasses delays the cement setting, but it is beneficial to the improvements of compressive strength, compatibility and microstructure. However, in addition to the fact that compressive strength is lowered, compatibility becomes poor, the later hydration is postponed and the microstructure gets loose, the scale of setting delay is also lessened when excessive cane molasses is used. The results also indicate it is logistically and economically feasible, also environmentally friendly that it is recycled as a cement grinding aid. These results are crucial to its sustainable and effective uses as well as the reuse of the waste containing similar matters. Additionally, this study also helps realize the sustainable production of cement, and also to contribute to the efforts at sustainable construction.

Preparation of polymer-based cement grinding aid and their performance on grindability

This paper described a chemical process called water-based free radical polymerization to synthesize a polymer-based grinding aid (PGA), which was characterized by infra-red spectroscopy (FT-IR) and used for the production of Portland cement (ground in a ball mill at a laboratory stage). For this purpose, reference cement was also produced without using PGA. All the cement mixtures were tested for specific surface area and particle size distribution. The changes of shape of particles and repose angles of ground cement were also tested to evaluate the flow characteristics of ground cement. Compared to a reference cement admixture, the addition of PGA led to significant gains in specific surface area, a fact that was attributed to the PGA’s ability to prevent agglomeration and powder coatings of ball. The results also indicated that PGA had obviously influences on particle size distribution of ground cement, which showed a narrower grading spectrum as the PGA dosage increased. Test results by SEM and repose angle method showed that PGA resulted in improvement of roundness and fineness of cement grains and fluidity of ground cement.

Intensification of Cement Grinding with Apply Grinding Aids with Modify Effect

For over 60 years technological additives used in process of grinding cement. Application of cement grinding aids can improve performance of ball mills, reduce specific energy consumption, and increase fluidity of cement during transportation and processing. Construction practice is characterized currently emergence and increasing use of so-called high-tech (effective) a new generation of concrete, suggesting the use of high quality cement. In work presents results of impact intensifiers on the grindability of cement based on different mineralogical composition of clinker. Offers original methodology for assessing of indicators intensifiers action on grinding process and qualitative characteristics of cement. Knowing positive and negative sides of each constituent component it is possible to try selection of compositions intensifiers with synergies effect considering mineralogical composition of clinker and material composition of cement. The presence of modifying component allows not only render intensifying effect in milling process, but to increase both early and late strength due to the formation of more dense and homogeneous structure of cement stone. It is shown that intensifiers with modifying additives allow not only affect on grinding process, but also on the process of hydration and morphology crystal hydrates, strength characteristics. In process of work we had determined, that among researched additives for two different cements, which differ from each other mineralogical composition, best results were obtained with used AI8 intensifier.

The Theoretical Research on Development Direction of Cement Grinding Aids

Cement grinding aids has been widely used in cement grinding process. The development of traditional compound cement grinding aids, such as triethanolamine and salts based has encountered a bottleneck. Synthesis of cement grinding aids can be improved by the molecular structure design of traditional cement grinding aids, or even lay aside the shackles of traditional cement additive and synthesize high-grinding effect, high performance and low cost cement grinding aids. In this paper, it has proposed two types of cement additives research direction，medium-small molecule and polymer synthesis system. Finally, it had introduced the application performance advantages of two new synthetic grinding aids, compared to triethanolamine and triisopropanolamine.

Research on the Application of Expanded Perlite Cement Grinding Aids

A kind of composite grinding aids was developed of expanded perlite and grinding aids M-1,and the effect of grinding on it was analyzed by cement powder fineness, specific surface area, laser particle size analysis, SEM image and cement mortar strength performance test. The composite grinding aids have outstanding grinding effect, which shield surplus electric charge, prevent the agglutination between particles, increase the standard water consumption, and decrease the condensation time. Furthermore, the influence of cement properties were tested, and results indicate that the total testing standards meet JC/T667-2004 of grinding aids.

Characterization of various cement grinding aids and their impact on grindability and cement performance

The aim of the present research work was the evaluation of six commercial grinding additives, which were used for the production of Portland cement (ground in a ball mill at a laboratory stage). For this purpose, a reference sample was also produced without using any admixture. The characterization of the grinding aids (GA) was carried out by Fourier transform infra-red spectroscopy (FT-IR) and gas chromatography/mass spectrometry (GC/MS). All the cement mixtures were tested for initial and final setting times, consistency of standard paste, flow of normal mortar and compressive strengths after 2, 7 and 28 days. In all cases the addition of grinding aids resulted in improvement of the specific surface and grindability index, a fact that was attributed to the additive ability not only to reduce resistance to comminution, but also to prevent agglomeration and powder coatings of ball and mill. The mortars made with cements ground with the addition of commercial additives, which contained triisopropanolamine (TIPA), exhibited higher strength at any age and higher setting times. On the other hand, the presence of triethanolamine (TEA) on the commercial grinding additives did not affect the mechanical properties of the produced cements but slightly decreased their setting times.

Novel pyrolysis-gas chromatography/mass spectrometric techniques for the characterization of chemical additives in portland cement and concrete

The application of pyrolysis gas chromatography mass spectrometry (py-GC/MS) has been improved for the determination of chemical additives that are either interground with cement clinker during the manufacture of Portland cement or admixed with a mixture of cement, sand, and stone, and water for the production of concrete. This technique has been found to be readily applicable for phenol-based cement grinding aids and naphthalene sulfonate formaldehyde condensate (NSFC)-based concrete admixtures. Furthermore, pyrolytic decomposition of a nitrite-based corrosion inhibitor incorporated into a concrete mixture was found to produce abundant dinitrogen oxide (N 2O), a unique indicator of the nitrite additive. Volatile methyl esters of fatty and rosin acid-based air entraining agents can be formed from the pyrolysis of powdered concrete treated with methanolic tetramethylammonium hydroxide (TMAH). Overall, the py-GC/MS analysis of cement and concrete has the potential to be far more specific and less tedious than the common extraction-spectroscopic based methods currently used. In-situ pyrolytic reactions can further expand the capability of py-GC/MS by volatilizing otherwise thermally stable or strongly adsorbed additives in cement and concrete.

Environmental assessment of the alkanolamines.

This review provides a summary of current information available on the environmental fate and aquatic toxicology of the alkanolamines. Because these materials are widely used, there is a need to understand their fate and effects in the environment. This assessment was confined to information regarding selected physical properties of the alkanolamines as well as their potential for degradation in the atmosphere, soil, surface water, and groundwater. In addition, their relevant aquatic toxicological information and bioconcentration potential were evaluated. In general, the alkanolamines have high water solubilities and low to moderate vapor pressures. Some are solids whereas others are liquids at room temperature. Aqueous solutions of the alkanolamines are basic, with the pKas decreasing with increased alkyl substitution. Predictions of the environmental distribution of these compounds, based on a unit world model of Mackay and Paterson, suggested that alkanolamines would partition primarily into the aqueous compartment at equilibrium, with the remainder distributed to the atmosphere. Only a very small fraction of these materials is expected to sorb to soil or sediments. However, adsorption mechanisms other than partitioning into the soil organic layer were not considered in this model. Since polar compounds may sorb to soil by alternate mechanisms, this model may underestimate the true adsorption potential and subsequent environmental distribution of the alkanolamines. Future work with these compounds should focus on other types of adsorption mechanisms that could impact the environmental distribution of the alkanolamines. Although only small amount of the alkanolamines are expected to partition to the atmosphere, they are expected to be removed by reactions with photochemically generated hydroxyl radicals. They may also be removed from the atmosphere by precipitation, due to their high water solubility. Because of the relatively low levels expected to be present in the atmosphere and the relatively short half-lives, the alkanolamines are not expected to adversely impact air quality. Alkanolamines have also been shown to be highly susceptible to biodegradation and are not expected to persist in the environment. Results from numerous studies have shown that these materials undergo rapid biodegradation in soil, surface waters, and wastewater treatment plants. Degradation rates for these compounds may vary, with half-lives routinely in the range of 1 d to 2 wk, depending on the length of acclimation period and other environmental factors. The relatively low bioconcentration factor (BCF) values reported for the alkanolamines indicate that they would not be expected to bioconcentrate in aquatic organisms. Available data on the toxicity of the alkanolamines to aquatic organisms suggest low toxicity to the majority of the species studied. Based on the facts that alkanolamines exhibit low aquatic toxicity, are shown to biodegrade in a wide range of environments, and exhibit no tendency to bioaccumulate, the routine manufacturing, use, and disposal of these materials are not expected to adversely impact the environment. With increased emphasis by consumers and regulatory agencies for industry to develop products that are "environmentally friendly," these properties of the alkanolamines make them an attractive choice for a wide range of applications.