硅酸盐学报

利用废酸溶解硅酸镁矿物制备水化硅酸镁胶凝材料

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宋强 ¹ , 何倩 ¹ , 聂娇 ¹ , 宋甜甜 ¹ , 周红 ² , 胡亚茹 ¹ , 陈延信 ¹ , 邓洋 ³ , 程福安 ¹

硅酸盐学报 | 研究论文 2025,53(11): 3168-3178

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硅酸盐学报 |研究论文 2025 , 53 (11) : 3168 -3178

利用废酸溶解硅酸镁矿物制备水化硅酸镁胶凝材料

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宋强¹, 何倩¹, 聂娇¹, 宋甜甜¹, 周红², 胡亚茹¹, 陈延信¹, 邓洋³, 程福安¹

作者信息

^1．西安建筑科技大学材料科学与工程学院，西安 710055

^2．陕西建材科技集团股份有限公司，西安 710018

^3．陕西富平生态水泥有限公司，陕西渭南 711709

通讯作者:

陈延信（1974—），男，博士，教授。

作者简介:

宋强（1980—），男，博士，副教授。

Preparation of Magnesium Silicate Hydrate by Dissolving Magnesium Silicate Minerals with Waste Acid

Qiang SONG¹, Qian HE¹, Jiao NIE¹, Tiantian SONG¹, Hong ZHOU², Yaru HU¹, Yanxin CHEN¹, Yang DENG³, Fuan CHENG¹

Affiliations

^1.College of Materials Science and Engineering Xi'an University of Architecture and Technology, Xi'an 710055, China

^2.Shaanxi Building Materials Technology Group Co., Ltd., Xi'an 710018, China

^3.Shaanxi Fuping Eco-Cement Co., Ltd., Weinan 711709, Shaanxi, China

Corresponding Author:

CHEN Yanxin (1974-), male, Ph.D., Professor. E-mail: yx_ch@126.com

SONG Qiang (1980-), male, Ph.D., Associate Professor. E-mail: sq_80@126.com

出版时间: 2025-11-20 doi: 10.14062/j.issn.0454-5648.20250134

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摘要

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为了探寻水化硅酸镁（M-S-H）胶凝材料更广泛、更低碳的原料来源，使用实验室废酸酸浸蛇纹石等3种天然硅酸盐矿物获得不溶残渣和Mg（OH）₂，并用残渣和Mg（OH）₂制备了M-S-H胶凝材料。采用XRD等手段表征了20，50 ℃和80 ℃水浴养护的试样结构，测试了3个温度养护试样的胶砂强度等性能。结果表明：HCl和H₂SO₄摩尔浓度分别为6.20 mol/L和7.77 mol/L的废酸能够溶解蛇纹石、海泡石和橄榄石，并得到纯度达到96%的Mg（OH）₂和SiO₂含量高于89%的残渣。随着养护温度的升高，M-S-H胶凝材料中的Mg（OH）₂含量降低，M-S-H相结合水量增加，硅氧四面体聚合程度增加。M-S-H胶凝材料试样3 d和28 d胶砂抗压强度可达12 MPa和40 MPa，并与结合水含量之间有一定的相关性，试样较高的早期强度得益于残渣中无定形二氧化硅的高活性，较好的砂浆流动性得益于残渣中含有一定的水分。

关键词

水化硅酸镁 / 硅酸镁矿物 / 酸浸法 / 胶凝材料

Abstract

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Introduction

Magnesium silicate hydrate (M-S-H) attracts significant attention as an alternative to traditional portland cement due to its unique properties, including reduced energy consumption during preparation. However, its synthesis typically requires MgO from calcined magnesite, which undermines the environmental benefits it provides. This study addresses these limitations by proposing a waste valorization strategy: recycling waste acid to dissolve naturally abundant magnesium silicate minerals (serpentine, olivine, and sepiolite) for M-S-H production. By combining acid waste management with mineral resource utilization, this approach not only avoids the energy-intensive MgO production process but also eases the ecological hazards caused by acid disposal.

Methods

The experimental involved three key stages: acid leaching, material preparation, and characterization. First, serpentine, olivine, and sepiolite were subjected to dissolution in a mixed waste acid solution (HCl: 6.20 mol/L, H₂SO₄: 7.77 mol/L) at 90 ℃ for 3 h under continuous mechanical agitation. The solid-to-liquid ratio was maintained at 1∶5 for acid leaching. After leaching, the insoluble residues (mainly amorphous silica) were separated with a centrifuge (Thermo Scientific ST 16R). The obtained residues were washed ultrasonically with deionized water 5 times to remove residual acid. Subsequently, the residue was dried in a vacuum drying oven at 50 ℃ for 24 h. The acid-leached filtrate was added into a 10 mol/L NaOH solution, with real-time pH monitoring until reaching pH 11.5. The obtained suspension was left to settle at room temperature for 24 h. The white flocculent precipitate was collected by vacuum filtration and dried at 100 ℃ for 24 h to obtain Mg(OH)₂-rich powder. The dried residue was mixed with Mg(OH)₂ powder at a ratio of n(SiO₂) ∶ n(MgO)=1.0∶1.4, and blended with water with a water-to-solid ratio of 1 ∶ 2 to form a paste. The paste was sealed in glass tubes and cured in water baths at 20, 50 ℃, and 80 ℃ for 3, 7, 14 d, and 28 d, followed by vacuum drying at 50 ℃ for 24 h prior to characterization. Mortar samples with the same residue-Mg(OH)₂ ratio were tested for compressive strength, fluidity, and drying shrinkage according to Chinese national standards.

Results and discussion

The residues contain 89%-96% amorphous SiO₂, and Mg(OH)₂ precipitates exhibit 96% purity. Promoting curing temperature significantly accelerates M-S-H formation. At the same age, the diffraction peak of Mg(OH)₂ is lower in samples cured at higher temperature. TG curves reveal 3 distinct mass loss: 50-350 ℃ (loss of physically bound water, Δw₁), 350-450 ℃ (Mg(OH)₂ dehydroxylation, Δw₂), and 450-750 ℃ (Si-OH dehydroxylation, Δw₃). The Δm₂ content decreases with age and elevated temperatures, indicating accelerated Mg(OH)₂ reaction. A linear relationship between Δm₂ and (Δw₂+Δw₃) is established. A decline is observed in the slopes of fitting line, from 0.96 (20 ℃) to 0.80 (50 ℃) and 0.76 (80 ℃), which indicates that the contribution from unreacted Mg(OH)₂ decreases while the formation of M-S-H is promoted with increasing temperature. The broadening and intensification of the exothermic peak near 850 ℃ (M-S-H recrystallization) in the DSC curve indicate enhanced maturation of M-S-H with increasing curing temperature. ²⁹Si NMR spectra indicate elevated curing temperatures reduced the relative content of Q¹, confirming enhanced polymerization of silicon-oxygen tetrahedra in M-S-H phases, though infinite chain structures were not formed. The diminished Q³_c signal (corresponding to talc-type 2∶1 layered structures) indicated a gradual decline in "transitional" M-S-H (Mg/Si = 0.9-1.1), while increased Q³_a (serpentine-like 1∶1 layers) reflected accelerated alignment of Mg/Si ratios with the raw material's composition (1.4). M-S-H gels form via Mg²⁺/H₃SiO₄^- polymerization into Q²/Q³ networks with minor Q¹, accelerated by elevated temperatures to yield serpentine-like layer structure. The M-S-H mortars demonstrated remarkable early strength (12-18 MPa at 3 d). This was attributed to the high reactivity of amorphous SiO₂ and the rapid dissolution of Mg(OH)₂. After 28 d, compressive strength reached 40 MPa at 80 ℃. The mortar exhibited superior fluidity (157-181 mm flow diameter) without any superplasticizer, enabled by 28%-32% moisture in residues. However, excessive drying shrinkage was observed.

Conclusions

The mixed waste acid effectively dissolved serpentine, olivine, and sepiolite, yielding Mg(OH)₂ (≥96% purity) and SiO₂-rich residues (>89% SiO₂). The polymerization degree of silicon-oxygen tetrahedra in the resulting M-S-H phases increased with rising curing temperature (from 20 ℃ to 80 ℃) and extended curing time (from 3 d to 28 d), leading to the formation of serpentine-like layered structures. The mortar exhibited high early strength (12-18 MPa at 3 d) and reached 40 MPa at 28 d, which is attributed to the high reactivity of silica residues and rapid dissolution of Mg(OH)₂. Although the inherent moisture in the residues and the absence of water consumption by Mg(OH)₂ contributed to excellent fluidity without adding superplasticizers, this combination still causes significant shrinkage.

Key words

magnesium silicate hydrate / magnesium silicate minerals / acid-leaching method / cementitious material

引用本文

宋强, 何倩, 聂娇, 宋甜甜, 周红, 胡亚茹, 陈延信, 邓洋, 程福安. 利用废酸溶解硅酸镁矿物制备水化硅酸镁胶凝材料. 硅酸盐学报, 2025 , 53 (11) : 3168 -3178 . DOI: 10.14062/j.issn.0454-5648.20250134

Qiang SONG, Qian HE, Jiao NIE, Tiantian SONG, Hong ZHOU, Yaru HU, Yanxin CHEN, Yang DENG, Fuan CHENG. Preparation of Magnesium Silicate Hydrate by Dissolving Magnesium Silicate Minerals with Waste Acid[J]. Journal of the Chinese Ceramic Society, 2025 , 53 (11) : 3168 -3178 . DOI: 10.14062/j.issn.0454-5648.20250134

基金

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陕西省科学技术研究计划(2024GX-YBXM-401; 2024GX-YBXM-370)
榆林市科技计划项目(CXY-2020-057)

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2025年第53卷第11期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250134

接收时间：2025-03-03
首发时间：2026-10-21
出版时间：2025-11-20

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出版历史

收稿日期：2025-03-03
修回日期：2025-03-27

基金

陕西省科学技术研究计划(2024GX-YBXM-401; 2024GX-YBXM-370)

榆林市科技计划项目(CXY-2020-057)

作者信息

^1．西安建筑科技大学材料科学与工程学院，西安 710055

^2．陕西建材科技集团股份有限公司，西安 710018

^3．陕西富平生态水泥有限公司，陕西渭南 711709

通讯作者:

陈延信（1974—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250134

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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