Engineering properties as a supplement cementitious material of ground copper reduction slag extracted valuable metal from Cu slag.

We have examined whether the copper reduction slag (CRS) generated after recovering valuable metals from copper slag (CS) by reduction process can be used as supplementary cementitious materials (SCMs). According to the test results, the Cu secondary slag with low Fe, Cu, and heavy metal contents had a suitable oxide composition for using as a SCM. CRS showed better grinding efficiency than that of ground blast furnace slag (GGBS). Ground CRS contributed to the formation of tobermorite under autoclaved curing conditions. The compressive strength of CRS mortar replacing 50 % of OPC generated 93 % of that of the OPC mortar. Based on the results of this study, we found that the CRS has highly appropriate engineering characteristics for using as SCMs for concrete. In addition, it is judged that the method of using secondary slag as a material for precast concrete produced under hydrothermal conditions can greatly contribute to the construction process of buildings by securing mechanical performance.

The Influence of Retreated Lithium Slag with a High Content of Alkali, Sulfate and Fluoride on the Composition and the Microstructure of Autoclaved Aerated Concrete.

In this paper, the possibility of retreated lithium slag (RTLS) with a high content of alkali, sulfate and fluoride as a partial replacement for fly ash (FA) to produce autoclaved aerated concrete (AAC) was investigated. The influence of the RTLS dosage on the AAC performance were examined. The composition and microstructure of hydrates as well as the microstructure of the RTLS-FA-based AAC compositions were determined by XRD, FTIR, TG-DSC and SEM. The results illustrated that the incorporation of RTLS changed the crystal structure and the microstructure of the tobermorite. With increased RTLS contents, the morphology of tobermorite was changed, and the grass-like tobermorite gradually transformed into network-like tobermorite. The newly formed tobermorite improved the mechanical performance of the AAC. Compared with the RTLS10, the content of tobermorite in the RTLS30 increased by 8.6%.

Effects of calcium-to-silicon ratio on the properties of fly ash-based tobermorite and its removal performance of Zn2+ and Mn2.

The effects of calcium-to-silicon ratio on the properties of fly ash (FA)-based tobermorite and its removal performance of Zn2+ and Mn2+ were studied. The calcium-to-silicon ratio had a significant effect on the structural properties of the tobermorite samples. The specific surface area, pore volume, and average pore size of mesoporous tobermorite samples with different calcium-to-silicon ratios (0.8TOB, 1.2TOB, and 1.6TOB) were much larger than those of FA, and those of 1.2TOB were the largest, which were 53.29 m2/g, 0.448 cm3/g, and 30.50 nm, respectively. The removal efficiencies of Zn2+ and Mn2+ by 1.2TOB were 84.19% and 47.67%, respectively, which were much higher than those of 0.8TOB (60.62% and 42.41%), 1.6TOB (46.69% and 24.31%), and FA (4.13% and 6.95%). The adsorption of Zn2+ and Mn2+ by 0.8TOB, 1.2TOB, and 1.6TOB was corresponding to the pseudo-second-order kinetic model and Langmuir isotherm model. Particularly, 1.2 TOB showed the highest maximum adsorption capacities of Zn2+ and Mn2+ calculated from the Langmuir model, which were 129.70 mg/g and 82.09 mg/g, respectively. Moreover, the adsorption mechanisms might be due to the combination with -OH and the interlayer adsorption of the samples. This research provides new insight into the fly ash-based adsorbents towards Zn2+ and Mn2+ in wastewater.

Preparation and characterization of high-ash coal slime-based soil amendment as well as investigations of its adsorption performance and mechanisms towards heavy metals in soil.

In this study, high-ash coal slime-based mineral soil amendment (MSA) was prepared via the hydrothermal method using high-ash coal slime as raw material, supplemented with activator calcium oxide and additive KOH solution. After hydrothermal treatment at 230 °C for 5 h, the original crystalline phase (quartz and kaolinite) of the high-ash slime was completely transformed into hydrotalcite zeolite, tobermorite, and silicate of potassium aluminosilicate, which has the largest specific surface area. The adsorption of Pb2+ and Cd2+ was adherent to the kinetic equation of secondary adsorption and Freundlich models, and the removal of Pb2+ and Cd2+ reached up to 362.58 mg g-1 and 64.67 mg g-1. The successive releases of SiO2 and CaO from MSA conformed to the Elovich equation, whereas the releases of SiO2 in Cd-containing environments and CaO in Pb- and Cd-containing environments more closely conformed to the power function; the releases of K2O all conformed to the first-order kinetic equation. The presence of Pb2+ and Cd2+ in the environment promotes the release of potassium and calcium elements with MSA's ion-exchange ability, and attenuates the release of silicon elements. Combining Pb2+ and Cd2+ with silicon resulted in the intolerant precipitation of 3PbO·2SiO2 and Cd2SiO4. The mineral precipitation mechanism is the most important mechanism of MSA in immobilizing heavy metals, accounting for 72.7%-80.5% of the total adsorption. Further contaminated soil immobilization experiments also showed that the application of MSA significantly reduced the bioavailability of soil heavy metals. When the MSA addition amount was 1.6%, the residual state increased by 63.58%. In conclusion, preparing MSA may effectively utilize coal-based solid waste with high added value.

Lanthanum-modified tobermorite synthesized from fly ash for efficient phosphate removal.

Phosphate removal from water by lanthanum-modified tobermorite synthesized from fly ash (LTFA) with different lanthanum concentrations was studied. LTFA samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer‒Emmett‒Teller specific surface area analysis. The results showed that the LTFA samples were mainly composed of mesoporous tobermorite-11 Å, and LTFA1 with a lanthanum concentration of 0.15 M had a high specific surface area (83.82 m2/g) and pore volume (0.6778 cm3/g). The phosphate adsorption capacities of LTFA samples were highest at pH 3 and gradually decreased with increasing pH. The phosphate adsorption kinetics data on LTFA samples were most accurately described by the Elovich model. The adsorption isotherms were in the strongest agreement with the Temkin model, and LTFA1 showed the highest phosphate adsorption capacity (282.51 mg P/g), which was higher than that of most other lanthanum-modified adsorbents. LTFA1 presented highly selective adsorption of phosphate with other coexisting ions (HCO3-, Cl-, SO42-, and NO3-). In addition, phosphate was adsorbed onto LTFA samples by forming inner-sphere phosphate complexes and amorphous lanthanum phosphate. This study provides technical support for development of efficient fly ash-based phosphate adsorbents.

Drought-resistant and water-retaining tobermorite/starch composite hydrogel for the remediation of cadmium-contaminated soil.

The objective of this work is utilizing fly ash to synthesize tobermorite (TOB) with a higher specific surface area and layered structure, and incorporating it into the starch/acrylic acid network to boost the drought resistance, water retention and heavy metal adsorption properties. The water absorption and water retention performance and cadmium adsorption characteristics of tobermorite/leftover rice-based composite hydrogel (TOB@LR-CH) were evaluated by water absorption swelling test, soil evaporation test and batch adsorption experiment. By adjusting the addition of TOB and other synthesized conditions, the swelling property (from 114.80 g/g to 322.64 g/g), water retention (71.80 %, 144 h) and Cd2+ adsorption characteristics (up to 591.36 mg/g) were significantly enhanced. Adding a moderate amount of TOB (2 wt%) provided the most uniform tobermorite dispersion during synthesis, and TOB2@LR-CH exhibited the most stable three-dimensional network and highest proportion of effective TOB. The adsorption behavior of cadmium on TOB2@LR-CH was more consistent with the pseudo-second-order kinetics and Langmuir isotherm models. Additionally, the regeneration test results displayed that the adsorption removal rate of cadmium by TOB2@LR-CH adsorbent remained stable after 5 cycles. This study demonstrates that TOB@LR-CH has good water absorption and water retention potential in arid and semi-arid soils, and also has potential application prospects in remediating Cd(II)-contaminated soil.

Hydrothermal alkaline synthesis and release properties of silicon compound fertiliser using high-ash coal slime.

High-ash coal slime is difficult to utilise as a boiler fuel, and its accumulation results in environmental pollution. In this study, we describe a new method for the preparation of high-ash coal slime silica compound fertiliser (HASF) using CaO-KOH mixed hydrothermal method to optimize the utilization of this industrial waste and relieve the pressure on the fertiliser industry. The coal slime (D0) used in this study and its dry basis ash content by 1 mol/L and 4 mol/L sulfuric acid pre-activation (D1, D4) were greater than 85%. The effective silicon content of D0, D1, and D4 silica compound fertilisers reached 30.24%, 31.24%, and 17.35%, respectively, and the sums of effective silica-calcium-potassium oxides were 57.28%, 58.87%, and 48.16%, respectively, under the optimal reaction conditions of 230 °C, 15 h, and 1 mol/L KOH, which met the market requirements, as determined using single-factor experiments. We used XRD, FTIR, and SEM-EDS analysis techniques to demonstrate that tobermorite and leucite were the main mineral phases of the compound fertiliser, and activated coal slime D4, which contains only quartz single crystals, required more demanding reaction conditions in the synthesis reaction. Subsequently, the cumulative release pattern of HASF silica was well described by the power function equation via repeated extraction and dissolution experiments, with the dissolution rate following D4 > D1 ≈ D0. Furthermore, 4 mol/L sulfuric acid pre-activation resulted in the enrichment of HASF combined with organic matter and increased the slow-release rate of HASF silica. Thus, the synthesized HASF could have potential application prospects in soil improvement and fertilisation.

Structural and Mechanical Properties of Doped Tobermorite.

As calcium silicate hydrate (C-S-H) is the main binding phase in concrete, understanding the doping behavior of impurity elements in it is important for optimizing the structure of cementitious materials. However, most of the current studies focus on cement clinker, and the doping mechanism of impurity elements in hydrated calcium silicate is not yet fully understood. The hydrated calcium silicate component is complex, and its structure is very similar to that of the tobermorite mineral family. In this study, the effects of three different dopants (Mg, Sr and Ba) on a representing structure of C-S-H-tobermorite-was systematically explored using densify functional theory (DFT) calculations. The calculations show that Mg doping leads to a decrease in lattice volume and causes obvious structure and coordination changes of magnesium-oxygen polyhedra. This may be the reason why high formation energy is required for the Mg-doped tobermorite. Meanwhile, doping only increases the volume of the Sr- and Ba-centered oxygen polyhedra. Specifically, the Mg-doped structure exhibits higher chemical stability and shorter interatomic bonding. In addition, although Mg doping distorts the structure, the stronger chemical bonding between Mg-O atoms also improves the compressive (~1.99% on average) and shear resistance (~2.74% on average) of tobermorillonite according to the elastic modulus and has less effect on the anisotropy of the Young's modulus. Our results suggest that Mg doping is a promising strategy for the optimized structural design of C-S-H.

Strength and Electrical Properties of Cementitious Composite with Integrated Carbon Nanotubes.

The main objective of this work was to study the effects of carbon nanotubes (CNTs) on the strength and electrical properties of cement mortar. Molecular dynamic simulations (MDSs) were carried out to determine the mechanical and electrical properties of a cementitious composite and its associated mechanisms. To model the atomic structure of a calcium silicate hydrate (C-S-H) gel, tobermorite 11Å was chosen. Single-walled carbon nanotubes (SWCNTs) embedded in a tobermorite structure were tested numerically. In particular, it was concluded that a piezoelectric effect can be effectively simulated by varying the concentration levels of carbon nanotubes. The deformation characteristics were analyzed by subjecting a sample to an electrical field of 250 MV/m in the z-direction in a simulation box. The results indicated a progressively stronger converse piezoelectric response with an increasing proportion of carbon nanotubes. Additionally, it was observed that the piezoelectric constant in the z-direction, denoted by d33, also increased correspondingly, thereby validating the potential for generating an electrical current during sample deformation. An innovative experiment was developed for the electrical characterization of a cementitious composite of carbon nanotubes. The results showed that the electrostatic current measurements exhibited a higher electric sensitivity for samples with a higher concentration of CNTs.

Novel Amorphous-Wollastonitic Low-Calcium Hydraulic Binders: A State-of-the-Art Review.

Because of the severe environmental impact of the CO2 emissions associated with the production of ordinary Portland cement (OPC) and the increasing demand for this commodity material, the development of alternative products has become a global concern. One alternative to OPC, or alitic-based clinkers, are amorphous-wollastonitic low-calcium hydraulic binders (AWLCs). This new class of hydraulic binders, described in the literature for the first time in 2015, may significantly reduce the CO2 emissions associated with its production, resulting from its lower calcium content, but also from the fact that its production technology can be fully electrified. In this paper, a state-of-the-art review is presented, providing a comprehensive description of the latest research, summarizing both the physicochemical and mechanical characteristics of this type of hydraulic binder, as well as possible routes for its production at an industrial scale.

Mixed solvent fabrication of tobermorite and the fixation of heavy metals in water and soil.

Here, tobermorite was prepared by a solvothermal technology using calcite and quartz with a mixed solvent of ethanol and water. Factors including reaction temperature, time and KOH content were studied to optimize the preparation procedure. To study the relationship between ethanol content-material structural characteristics-adsorption capacity, a series of materials were prepared in different mixed solvent proportions of ethanol and water, and their structural characteristics and adsorption capacity were compared. We found that the adsorption capacity of different samples for Pb2+ and Cd2+ was positively correlated with negatively correlated with the surface area and negatively correlated with the crystallinity of materials. Then, the material prepared by 30% ethanol solution (30-T) with the best adsorption performance was used for further research; the results were fitted by kinetic and thermodynamic models, and adsorbed materials were analyzed by various characterizations, suggesting that the adsorption process was ascribed to comprehensive pathways including ion exchange, chemical precipitation, and surface-complexation. Then, the 30-T was further used to remediate heavy metals contaminated soil, and the remediation effect was examined by the DTPA-extractable method and the European Community Bureau of Reference (BCR) sequential extraction method. The DTPA-extractable results showed that tobermorite observably reduced the bioavailability of Pb and Cd, and the BCR results suggested that the acid-soluble and reducible fractions of Pb and Cd were transformed to the oxidizable and residual fractions after remediation. In summary, tobermorite has great potential in the remediation of heavy metal polluted-aquatic environment/system and soil.

Preparation of amino-functionalized fly ash based tobermorite for enhanced removal of Cr(VI).

Amino-functionalized fly ash based tobermorite (NH2-FAT) was prepared via a two-step process including a hydrothermal preparation of fly ash based tobermorite (FAT) from fly ash (FA) and the impregnation of 3-aminopropyltriethoxysilane (APTES). The characteristics of FA, FAT, and NH2-FAT were systematically measured. The removal capacity of Cr(VI) by FAT and NH2-FAT were comparatively studied. The results indicated that the NH2-FAT presented excellent removal efficiency towards Cr(VI) in the condition of pH of 2. The adsorption capacity of Cr(VI) by NH2-FAT in this study was up to 498.39 mg/g resulted from Langmuir model, which was more superior to that of FAT, other reported FA based adsorbents and most amino-functionalized adsorbents. Furthermore, the removal mechanisms of Cr(VI) by NH2-FAT were ascribed to both electrostatic attraction and reduction to Cr(III) by amino groups. Overall, this work indicates the NH2-FAT is a promising adsorbent for treating wastewater containing Cr(VI), and provides a new utilization method of FA.

Study on Crystal Growth of Tobermorite Synthesized by Calcium Silicate Slag and Silica Fume.

In order to high-value utilize the secondary solid waste calcium silicate slag (CSS) generated in the process of the extraction of alumina from fly ash, in this paper, tobermorite was synthesized using CSS and silica fume (SF) at different hydrothermal synthesis times. The hydrothermal synthesis was evaluated by means of XRD, SEM, EDS, and micropore analysis, and the results discussed. The results indicate that ß-dicalcium silicate, the primary phase in the CSS, partially hydrates at the beginning of hydrothermal synthesis conditions to form mesh-like crystal C-S-H (calcium-rich) and calcium hydroxide. It then reacts with SF to form yarn-like crystal C-S-H (silicon-rich) and then furtherly grows into large flake-like crystal C-S-H (silicon-rich) at 3 h. When the synthesis time is 4 h, ß-dicalcium silicate completely hydrates, and crystal C-S-H (calcium-rich) and calcium hydroxide further reacts with large flake-like crystal C-S-H (silicon-rich) to generate medium flake-like tobermorite. With the increase in time, the crystal of hydrothermal synthesis grows in the order of medium flake-like tobermorite, small flake-like tobermorite, strip flake-like tobermorite, fibrous-like tobermorite, and spindle-like tobermorite, and the APV, APD, and SSA show a trend of decreasing first, then increasing, and then decreasing. Meanwhile, strip flake-like tobermorite with a higher average pore volume (APV), average pore diameter (APD), and specific surface area (SSA) can be synthesized at 6 h.

Highly Efficient Cd2+ Removal Using Tobermorite with pH Self-Adjustment Ability from Aqueous Solution.

Cadmium (Cd), as a type of heavy metal, can increase the incidence of many diseases, even in low concentrations. In this study, tobermorite was hydrothermally synthesized and then applied to adsorb Cd2+ from an aqueous solution. The physicochemical characteristics of the synthesized tobermorite were detected, and the results indicated that the well-crystallized tobermorite had a lot of mesopores and a large specific surface area of 140.92 m2/g. It acquired a pH self-adjustment ability via spontaneously releasing Ca2+ and OH- into the aqueous solution. The effects of different factors on Cd2+ removal were investigated. For Cd2+, the removal efficiency could reach 99.71% and the maximum adsorption capacity was 39.18 mg/g using tobermorite. The adsorption data was best fitted with the pseudo-second-order kinetic and Langmuir isotherm models. In addition, there was no strict limit on the solution pH in Cd2+ adsorption because the tobermorite could adjust the solution pH to an alkaline atmosphere spontaneously. The efficient removal of Cd2+ using tobermorite was a result of surface complexation and ion exchange.

Subcritical hydrothermal treatment of municipal solid waste incineration fly ash: A review.

Municipal solid waste incineration fly ash (MSWI-FA) is a hazardous waste generated from the incineration process, and the harmless treatment of MSWI-FA has attracted widespread attention. Subcritical hydrothermal treatment is competitive in achieving the harmless treatment and resource recycling of MSWI-FA. It exhibits excellent performance in degrading dioxins, stabilizing heavy metals, and converting MSWI-FA into zeolite or tobermorite at low temperatures. This paper clearly introduces the characteristics of MSWI-FA, roundly summarizes the current research status of treating MSWI-FA by subcritical hydrothermal methods, and deeply clarifies the mechanisms of dioxins degradation, zeolite/tobermorite synthesis, and heavy metals stabilization. Considering the research status of handling MSWI-FA by subcritical hydrothermal methods, future research directions are proposed. Owing to the advantages of high efficiency, energy-saving, and environmental sustainability, subcritical hydrothermal treatment of MSWI-FA exhibits promising prospects for industrialization.

Assessment of Pozzolanic Activity of Ground Scoria Rocks under Low- and High-Pressure (Autoclave) Steam Curing.

Two sources of natural scoria rocks were procured and ground for use in concrete as natural pozzolans (NP1 and NP2). The evaluation of their pozzolanic reactivity is carried out using different techniques and approaches. The primary goal of employing these techniques is to monitor the amount of portlandite (CH=Ca(OH)2) consumed during steam curing at low or high pressure. The pozzolanicity of NP powders is determined either directly by monitoring CH variation or indirectly by compressive strength and microstructure development. Autoclave curing is known to stimulate the pozzolanicity of the inert siliceous and aluminosiliceous materials under its high-pressure steam conditions. Both steam-curing conditions were applied in this investigation. In this study, X-ray diffraction, scanning electron microscope, thermogravimetric, Fourier transform infrared, and isothermal analyzers were used. It is concluded that the nature and types of minerals in SR determine their pozzolanic reactivity as either low-pressure steam-reactive or high-pressure steam-reactive cementitious materials. Due to the nature of their silicate structures, notably single-chain or 3D-framework structures, plagioclase feldspars (albite-anorthite) minerals are high-pressure steam-reactive minerals, whereas pyroxene (enstatite and diopside) minerals are low-pressure steam-reactive minerals. Using high-pressure steam curing, varied replacement levels of up to 60% were achieved in NP1, with a consistent strength activity index (SAI) of 99%, while an SAI of 79% was obtained with NP2. During low-pressure steam curing, NP1 and NP2 consumed around 72 and 80% of portlandite, respectively, demonstrating their relative pozzolanic reactivity. When compared to the control concrete mix, the strength activity indices of NP1, NP2, and class F fly ash in their normal concrete mixes reached 74.3, 82, and 73.7%, respectively, after 56 days of normal curing conditions.

Influence of Industrial Metakaolin Waste on Autoclaved Fiber Cement Properties Changes in Standard Fire Environment.

An investigation was conducted on the influence that industrial metakaolin waste (IMW) has on the properties of autoclaved fiber cement composition (FCC) samples. FCC samples were made from fiber cement plate's typical components using the same proportions. In samples, IMW was used instead of cement in 10%, 20%, 30% proportions and in 50%, 100% proportions instead of ground quartz. Differential thermal analysis (DTG), thermogravimetric analysis (TGA), ultrasound pulse velocity (UPV), density, porosity and optical microscope (OM) research methods were used to identify the micro and macrostructure of samples. Mechanical properties were evaluated using flexural and compressive strength research methods. It was established that IMW was used instead of cement in fiber cement composition samples up to 10% and in fiber cement composition samples instead of ground quartz forms density microstructure structure because of Al-rich tobermorite. As a result, the flexural and compressive strength increased. Samples with higher content of IMW instead of cement had unreacted IMW and a less dense microstructure. In this case, flexural and compressive strength decreased. All FCC samples were fired in a standard fire curve (ISO 842) for 30 min. Samples of mechanical properties were established by doing flexural and compressive strength tests, and which results showed the same trends.

Synthesis of High Crystallinity 1.13 nm Tobermorite and Xonotlite from Natural Rocks, Their Properties and Application for Heat-Resistant Products.

The main measure to reduce energy losses is the usage of insulating materials. When the temperature exceeds 500 °C, silicate and ceramic products are most commonly used. In this work, high-crystallinity 1.13 nm tobermorite and xonotlite were hydrothermally synthesized from lime and Ca−Si sedimentary rock, opoka. By XRD, DSC, TG and dilatometry methods, it has been shown that 1.13 nm tobermorite becomes the predominant compound in stirred suspensions at 200 °C after 4 h of synthesis in the mixture with a molar ratio CaO/SiO2 = 0.83. It is suitable for the production of insulating products with good physical−mechanical properties (average density < 200 kg·m−1, compressive strength ~0.9 MPa) but has a limited operating temperature (up to 700 °C). Sufficiently pure xonotlite should be used to obtain materials with a higher operating temperature. Even small amounts of semi-amorphous C−S−H(I) significantly increase its linear shrinkage during firing. It has also been observed that an increase in the strength values of the samples correlated well with the increase in the size of xonotlite crystallites. The optimal technological parameters are as follows: molar ratio of mixture CaO/SiO2 = 1.2; water/solid ratio W/S = 20.0; duration of hydrothermal synthesis at 220 °C­8 h, duration of autoclaving at 220 °C­4 h. The average density of the samples was ~180 kg·m−1, the operating temperature was at least 1000 °C, and the compressive strengths exceeded 1.5 MPa.

Waste Originating from the Cleaning of Flue Gases from the Combustion of Industrial Wastes as a Lime Partial Replacement in Autoclaved Aerated Concrete.

This paper aims to study the suitability of partial replacement of lime by waste originating from the cleaning of flue gases from the combustion of industrial wastes in the production of autoclaved aerated concrete (AAC). The compressive strength, bulk density, pore structure, phase composition, and microstructure of hydration products of the AAC were analyzed. According to the results, the addition of the waste can effectively enhance the mechanical properties of AAC due to the differences in morphology of hydration product-1.1 nm tobermorite and related dense microstructure. The pore size distribution was significantly influenced by waste addition, which was one of the main reasons for the increase in thermal conductivity. The XRD and SEM results showed that foreign ions introduced with the wastes affect the synthesis of 1.1 nm tobermorite. Moreover, it was shown that waste containing a high content of CaO can be used as lime replacement, which allows reducing CO2 emissions during the AAC production process.

Preparation of hydrothermally solidified materials from waste cathode ray tube panel glass for construction applications.

Solidification of cathode ray tube (CRT) panel glass was carried out using a hydrothermal processing method. In this way, the glass powder was first compacted in a mold at 20 MPa, and then hydrothermally cured in an autoclave under saturated steam pressure at 200 ℃ for 6 h. The CRT panel glass was then hydrothermally solidified by the formation of tobermorite (Ca5Si6O16(OH)2·4H2O), which was encouraged by the addition of slaked lime (Ca(OH)2). The strength of solidified specimen heavily depended on the amount of tobermorite formed, with higher concentrations of tobermorite producing commensurately greater mechanical strength. With the addition of Ca(OH)2 at 20-30% by mass, the specimen achieved a bending strength of approximately 16 MPa, which was sufficiently great for using as a construction material. As such, there is cause to believe that the hydrothermal processing method used here may have great potential for resource utilization of CRT panel glass, and the performance of the product is suitable for use as building materials.