Utilization of nickel slag as raw material in the production of Portland cement for road construction

Construction and Building Materials 193 (2018) 426–434

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Utilization of nickel slag as raw material in the production of Portland cement for road construction Qisheng Wu a,⇑, Yang Wu b, Weihong Tong b, Hongen Ma b a b

School of Materials Science and Engineering, Yancheng Institute of Technology, Jiangsu, Yancheng 224051, PR China School of Materials Science and Engineering, Jiangsu University, Jiangsu, Zhenjiang 212013, PR China

h i g h l i g h t s
Use nickel slag as raw material to produce Portland cement for road construction.
The influence of calcination conditions on the properties of cement was studied.
Cement’s mineralogical characteristics were not affected by nickel slag.

a r t i c l e

i n f o

Article history: Received 27 June 2018 Received in revised form 27 September 2018 Accepted 15 October 2018

Keywords: Nickel slag Portland cement Road construction Wear resistance

a b s t r a c t This paper aims to use nickel slag as raw material to produce Portland cement for road construction. The burnability of cement raw meal with different contents of nickel slag was studied. The mineral compositions of prepared clinker and the hydration products of prepared cement were analyzed by X-ray diffractometry. The microscopic morphology of the clinker and hydration products were characterized by metallographic microscope and scanning electron microscope. The f-CaO content of the clinker, the mechanical properties and wear resistance of the cement pastes were tested. The result showed that the addition of nickel slag reduced the f-CaO content of clinker and improved the burnability of cement raw meal. Additionally, the hydration degree and the bending strength of cement paste were increased. When a proper amount (14 wt%) of nickel slag was incorporated into the raw materials and the sintering temperature was setted at 1350 °C, the 28-day compressive strength, bending strength and wear amount of cement paste were 52.4 MPa, 14.5 MPa and 2.1 kg/m2, respectively. Ó 2018 Elsevier Ltd. All rights reserved.

1. Introduction Nickel slag is a granulated slag formed by natural cooling or water quenching of a melt formed during the smelting process of nickel metal, which contains FeO, SiO2, Al2O3 and MgO as the main components [1]. For every ton of nickel produced, about 6–16 tons of nickel slag are generated and discharged in China [2]. In recent years, nickel production in China is relatively stable. The annual output of nickel slag reaches about 4 million tons, but its utilization rate is as low as 10%. Nickel slag contains a small amount of heavy metal elements such as Ni, Co and Cu. The disposal of nickel slag not only occupies a large area of land, but also is harmful to the environment [3]. To address this problem, researchers have conducted extensive research on the comprehensive utilization of nickel slag. The most

⇑ Corresponding author. E-mail address: [email protected] (Q. Wu). https://doi.org/10.1016/j.conbuildmat.2018.10.109 0950-0618/Ó 2018 Elsevier Ltd. All rights reserved.

important ones are: (i) the extraction of valuable metals from nickel slag. Nickel, iron, copper and other elements in nickel slag can be recovered by an acid leaching process and a selective reduction-magnetic separation process [4–7]. However, with the improvement of nickel metallurgical process, the content of extractable metals in nickel slag becomes very low. (ii) The preparation of crystallized glass. The main components of nickel slag, such as calcium, silicon, magnesium, aluminum and other oxides, are also the important components of glass [8–10]. However, only a low content of nickel slag is used in the preparation of glass-ceramics and it will easily induce secondary pollution. (iii) The production of cement and concrete: as additive in the preparation of Portland cement or substitute of aggregates [11–14]. (iv) The production of building materials: as raw materials for building blocks, autoclaved products, unburned bricks, and geopolymers [1,15,16]. (v) The preparation of mine filling materials: the flash furnace water quenched nickel slag is used as filling aggregate to meet the pressure and tensile strength requirements of mine filling process [17,18].

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Q. Wu et al. / Construction and Building Materials 193 (2018) 426–434 Table 1 The chemical compositions of raw materials (wt%). Oxides

LOI

CaO

SiO2

Al2O3

Fe2O3

MgO

SO3

Total

Limestone Fly ash Nickel slag Clay Steel slag Gypsum

39.06 3.28 1.29 6.88 0.61 19.63

53.35 2.96 2.4 4.25 29.47 31.68

2.84 54.37 44.89 65.4 17.65 1.20

0.78 32.09 6.6 12.18 5.52 0.50

1.81 4.43 15.59 4.5 31.59 0.24

0.51 1.15 26.89 1.9 7.8 2.02

0.18 0.66 0.18 – – 43.60

98.53 98.94 95.26 95.11 92.64 98.87

In 2017, China’s cement production volume reached 2.316 billion tons and a lot of energy and resources were required in the production process. However, the raw material resources used for production are limited and mostly belong to non-renewable resources. Many scholars have explored and studied the use of steel slag [19–21], copper tailings [22,23], and phosphorus slag [24,25] as raw materials to prepare cement clinker. The results have proved the feasibility of some industrial wastes as raw materials for cement production. In this paper, nickel slag was used as a silica calibration material to prepare Portland cement clinker for road construction. The burnability of raw materials prepared from nickel slag and other ingredients under different compatibility conditions was studied. The mineral compositions of prepared clinker and the mechanical properties and hydration products of prepared cement were analyzed. The results might provide useful information for the effective utilization of nickel slag.

2. Materials and methods 2.1. Materials The road Portland cement was prepared under laboratory conditions from the following raw materials: nickel slag, limestone, fly ash, clay, steel slag, gypsum, and fluoride. Nickel slag was acquired from a nickel slag storage yard of Delong Nickel Industry Company in Xiangshui economic development area, Jiangsu Province, China. Fly ash was provided by Yancheng Power Plant (Yancheng, Jiangsu Province, China). The gypsum used here was desulfurized gypsum. The main mineral of fluorite was CaF2 and it contained no other crystalline phases. The chemical analysis results of the raw materials are listed in Table 1. Since the nickel slag is formed under a reducing atmosphere and contains sulfide, the loss on ignition is negative. The XRD analysis results of nickel slag are shown in Fig. 1 and the trace element content of nickel slag are listed in Table 2. Dosing scheme for cement are list in Table 3. 2.2. Design and methodology for the synthesis of clinker According to the special requirement of road Portland cement for wear resistance and the provisions in GB13693-2005 for clinker minerals (C4AF  16%, C3A < 5%), the dosage plan needs to enable high iron content and low IM (alumina modulus) content. The design of the raw meals was based on the predictions of Bogue equations. The quality indices KH (the lime saturation factor), SM (silica modulus) and IM were calculated according to Eqs. (1)– (3), respectively:

KH ¼

%CaO  1:65%Al2 O3  0:35%Fe2 O3 2:8%SiO2

ð1Þ

SM ¼

%SiO2 %Al2 O3 þ %Fe2 O3

ð2Þ

IM ¼

%Al2 O3 %Fe2 O3

ð3Þ

Fig. 1. XRD pattern of nickel slag.

Table 2 Trace element content of nickel slag. Element

Cr

Mn

K

Ti

Na

Ni

Ba

Zn

Content

1.5

0.535

0.159

0.0755

0.0809

0.0607

0.0331

0.0202

Table 3 Dosing scheme for cement (wt%). Dosing scheme

Limestone

Fly ash

Nickel slag

Clay

Steel slag

Gypsum

CaF2

KH

SM

IM

A B C D E

74 73 75 70 65

4 2 2 3 3

14 20 18 15 15

– 4 4 4 2

7 – – – –

0.6 0.6 0.6 8 15

0.4 0.4 0.4 1 1

0.90 0.80 0.88 0.87 0.90

1.31 1.91 1.90 1.88 1.79

0.67 0.64 0.66 0.77 0.74

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2.3. Physical and mechanical tests for clinker and cement

Fig. 2. f-CaO contents of clinkers under different dosing schemes at different calcining temperatures.

For the preparation of clinkers, raw materials were individually milled in a planetary mill to a particle size <80 lm. After mixing and homogenizing, blocks with an approximate size of 25  25  25 mm were formed to use a 5-ton hydraulic press. The specimens were then dried for 24 h at 110 °C, followed by calcination at set temperature (1250, 1300, 1350 and 1400 °C) for 1 h and then cooling in the air. The content of free lime in clinker was determined by the glycerin-alcohol method according to GB/T 1762008 ‘‘Chemical Analysis of Cement”. The clinker was polished and etched with a 1% Nital solution, and its mineral morphology was observed using a metallographic microscope. To produce cement, the clinker was ground in a planetary mill to a particle size of less than 80 lm. After grinding, 5 wt% of desulfurization gypsum was added. Since their particle sizes were also smaller than 80 lm, the mixture could be relatively easily homogenized. Cement (c) was mixed with water (w) at a ratio of 0.3 (w/c). The strength was measured according to GB/T 17671 ‘‘Method of testing cements–Determination of strength”. The wear-resisting

Fig. 3. XRD patterns of clinkers under different dosing schemes and at different calcination temperatures. The main minerals identified are: a-C3S; b-C2S; c-C4AF; d-C3A; eMgO; f-CaO; g-CaMgSi2O6; h-Mg2Si5Al4O18.

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performance was tested in accordance with JC/T 421 ‘‘Method of wear abrasion for harden mortar”. The X-ray diffraction (XRD) spectra of different samples were obtained with a DX-2700 diffractometer (Dandong, China) with copper Ka radiation at 30 mA and 50 kV. A step size of 0.04°

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was selected over a 2h range of 5–70°. The microstructure of the samples at different stages was observed with a JEM-2100F field emission scanning electron microscope (FESEM). The fractured surfaces of the samples were coated with Au prior to examination.

Fig. 4. Photographs of polished sections of clinkers under different dosing schemes calcined at 1350 °C: (a)–(e): Schemes A–E. (500).

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Fig. 5. SEM-EDS analysis results of clinker under dosing scheme A.

Q. Wu et al. / Construction and Building Materials 193 (2018) 426–434

3. Results and discussion 3.1. Chemical and mineralogical characteristics of nickel slag According to the XRD and XRF results shown in Fig. 1 and Table 1, the main chemical components of nickel slag are SiO2, MgO and Fe2O3, and the main mineral components are forsterite, ferroan, clinoenstatite, akermanite and quartz. In addition to the basic chemical compositions, nickel slag also contains traces of Cr and Ni, etc. The Cr can act as a mineralizer to promote the formation of alite by solid solution, thereby improve the burnability of the raw meal [19,26]. Although the content of MgO in the nickel slag is relatively high, MgO mainly exists in the mineral form of olivine. Moreover, because of the low content of nickel slag incorporated into the raw materials, the MgO content in the clinker will not be too high. 3.2. Characterization of clinker Fig. 2 shows the f-CaO contents of clinkers under different dosing schemes. The results show that the f-CaO contents of all clinkers,

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except for under scheme E, are less than 1%, indicating that the clinkers were calcined well. The high content of f-CaO in the clinker under scheme E may be due to the high incorporation of gypsum, which results in the incomplete reaction. When the content of nickel slag is in the range of 14–20 wt%, the f-CaO content of the clinker changes little and is within the standard control range. This indicates that the burnability of the raw meal in this range is good. XRD analysis was performed to further understand the mineral compositions of clinkers calcined at different temperatures and determine the optimal preparation process (Fig. 3). Fig. 3 shows that the mineral compositions of each clinker include C3S, C2S, C3A, C4AF and a small amount of MgO (olivine), CaO, cordierite (ɑ-Mg2Al4Si5O18) and diopside (CaMg(Si2O6)). At calcination temperature of 1250 °C, the intensities of the diffraction peaks of C3S and CaO increase with the increasing nickel slag content, whereas the intensity of the diffraction peak of periclase changes little (Fig. 3a). When the nickel slag content remains the same, the C3S and C2S diffraction peaks become weaker with increase in gypsum content. This indicates that although the content of gypsum is high, the calcium is not fully involved in the reaction. Therefore, replacement of limestone with a large amount of

Fig. 6. Compressive strength of cements prepared under different dosing schemes: (a)–(d): Schemes A–D.

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desulfurized gypsum is not conducive to the calcination of clinker. At calcination temperature of 1300 and 1350 °C, the intensities of the diffraction peaks of C4AF and C3S increase first and then decrease as the nickel slag content increases, and the intensity of C2S diffraction peak gradually increases with increase in nickel slag content (Fig. 3b and c). An increase in the alkali content in the raw materials reduces the firing temperature of the clinker and increases the amount of liquid phase. Thus, the alkali components play a significant role in promoting the melting process. However, when the content of nickel slag is too high, the content of alkali components will be too high. K2O and Na2O will replace CaO to form alkali compounds and CaO will be precipitated. This makes it difficult for C2S to absorb CaO to form C3S, and leads to an increase in the f-CaO content of clinker, thus reducing the quality of clinker. At calcination temperature of 1400 °C, the mineral compositions of each sample are consistent with those at other calcination temperatures (Fig. 3d). Overall, with the exception of clinker under scheme E, the clinker in each group is in a good state of calcination, with the best mineral compositions obtained at 1350 °C. In order to further understand the microstructure of clinker, the polished sections of the clinker calcined at 1350 °C was examined by optical microscopy.

Fig. 4 shows that each clinker contains a few round-grained belite, but the shapes of alite grains are different. Alite grains in Fig. 4a mainly present planar and columnar shapes with uniform size. The reason why alite grains are blunt shown in Fig. 4b may be that the clinker under dosing scheme B is overheated at this temperature (1350 °C) to increase the amount of liquid phase and erosion. Alite grains in Fig. 4c appear to be incomplete due to erosion by the low-alkalinity liquid phase. In Fig. 4d, alite grains exhibit round and blunt corners, and have a large amount of round-grained belite. Dendritic growth of crystals is observed in Fig. 4e, indicating that the clinker is in an overheated state. Based on above observations, we can obtain that the mineral structure of clinker under dosing scheme A is the best developed, the crystal size is uniform and the structure is complete. A proper amount of well-structured Alite with uniform grain size contributes to the quality of clinker, so the sample under dosing scheme A has the best performance. Fig. 5(a) demonstrates that there are many hexagonal platelets of alite in clinker under dosing scheme A and they appear to be well formed, with average size of 20–40 lm. There are also a small amount of acicular f-CaO in the clinker. Fig. 5(b) and (c) show that there are also round-grained belite in the clinker. After amplifica-

Fig. 7. Bending strengths of cements prepared under different schemes: (a)–(d): Schemes A–D.

Q. Wu et al. / Construction and Building Materials 193 (2018) 426–434

tion, it can be clearly seen that there are obvious crystal lines on the surface of belite. There are also amorphous MgO particles and many dendritic mesophases (mainly iron-aluminate minerals) distributed among belite. These results are consistent with those in Fig. 4. 3.3. Characterization of cement The f-CaO content in the clinker under scheme E is so high that the setting time of the prepared cement exceeds 24 h and the strength is also too low. Considering these problems, cement prepared under scheme E is not discussed here. Fig. 6 suggests that the early strength of each type of cement is relatively low, but their strengths increase rapidly with further extension of time. The compressive strength of the cement paste prepared under scheme A reaches 42.5 grade at calcination temperature of 1350 °C and 1400 °C (Fig. 6a). When the content of nickel slag is 20 wt% (scheme B), the 28-day compressive strength of cement is lower

Table 4 Abrasion performance of cement mortar at 28-day hydration age/kg/m2. Dosing scheme

1250 °C

1300 °C

1350 °C

1400 °C

A B C D E

4.3 3.9 3.4 3.5 4.6

3.6 3.5 3.1 3.1 4.9

2.1 3.8 2.4 2.9 4.8

2.2 3.6 2.8 3.2 4.7

Fig. 8. XRD patterns of cement pastes at hydration ages of 3, 7 and 28 days.

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than scheme A (Fig. 6b). This indicates that the excessive incorporation of nickel slag will reduce the strength development of cement. In Fig. 6d, 8 wt% of gypsum is incorporated, which increases the IM of the clinker and reduces the amount of limestone used. Although the compressive strength of prepared cement paste reaches 32.5, its overall strength performance is lower than that of cement prepared under scheme C (Fig. 6c). This is because when the KH and the SM remain constant, the C3A content in the clinker increases while the C3S content decreases with increase in IM. This leads to a detrimental effect on the early strength development. In general, the compressive strength of cement is relatively high when the content of nickel slag is 14 wt% or 18 wt%. Similar to compressive strength, the bending strength of each cement also increases with the extension of time (Fig. 7). Notably, the addition of nickel slag has little effect on the bending strength of cement. The bending strength of each sample cured in the early age is relatively low, whereas the late bending strength is relatively high, but its dispersion is large, and the regularity has no obvious compressive strength. The 28-day bending strength of the cement paste prepared by the preferred preparation process is higher than the 52.5 grade road cement bending strength standard. The strength development of the cement prepared at 1350 °C is the best; the content of C3S in the clinker prepared at 1300 °C is smaller, and the content C2S is higher than the 1350 °C sample, resulting in a lower cement strength; the clinker prepared at 1400 °C is overburnt, resulting in an increase in liquid phase, too much large particle C3S is generated, which is not conducive to its strength. The optimal preparation process is: the contents of nickel slag, limestone, fly ash, steel slag, desulfurized gypsum, and calcium fluoride (weight percentage) are 14%, 74%, 4%, 7%, 0.6%, and 0.4%, respectively. The calcination temperature is 1350 °C. The heat preservation time is 60 min. The clinker prepared by this process has the optimal performance, and the strength of the prepared cement could reach 42.5 grade. Table 4 shows the results of the abrasion performance of prepared road cements after 28 days of curing. In general, the results of wear resistance of cements are not satisfactory, and only a few samples meet the wear resistance requirements of national standards (The GB 13693-2005 requires that the 28-day wear abrasion of road Portland cement should be no more than 3.0 kg/m2). Slag is used as an iron-corrected raw material and to partially replaced clay, and the cement prepared only by clinker and gypsum shows poor performance. On above basis, scheme A and calcination temperature of 1350 °C were selected as the optimal scheme and calcination temperature, respectively. The composition (Fig. 8) and microstructure (Fig. 9) of hydration products in cement prepared under the optimal conditions were studied. Fig. 8 shows the XRD patterns of cement pastes cured for 3, 7 and 28 days. The hydration products of cement samples at all ages are basically the same and mainly include C3S, C2S, Ca(OH)2, ettrin-

Fig. 9. SEM images of cement pastes at different ages. (a)-3 d; (b)-28 d; (c)-28 d.

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gite (AFt) as well as a small amount of MgO and Mg(OH)2. An increase in the curing age reduces the intensities of the characteristic peaks of C3S in the samples, whereas increases the intensities of the AFt peak. This indicates that C3S in clinker gradually produces AFt gels, which leads to increasing in the strength of sample, and the results are consistent with the intensity changes. The lower intensity of Ca(OH)2 peak at early hydration age means a lower early hydration rate of cement. The intensity of Ca(OH)2 peak increases slightly with increase of hydration age, which is related to the higher C2S content in the clinker. C3S and C2S are continuously hydrated to form Ca(OH)2 and AFt gels, and thus the intensities of C3S and C2S peaks decrease with the extension of curing time. Fig. 9 shows the SEM images of cement samples at different hydration ages. At 3-day hydration age, the hydration products are acicular ettringite with size of 1–2 lm and flaky calcium hydroxide (Fig. 9a). The crystal growth is incomplete and there are large holes on the crystals. At 28-day hydration age, the amount of gelled material gradually increases, forming a dense coating on the surface of the sample (Fig. 9b). The ettringite exists in the form of long fibre (Fig. 9c), intertwining with each other and forming a network structure, which helps to improve the performance of the sample. 4. Conclusions This article used nickel slag as raw material to produce road Portland cement. The effects of nickel slag content, desulfurized gypsum content and calcining temperature on the performance of raw material, clinker and cement paste were studied. The conclusions are as follows: (1) It is feasible to produce road Portland cement with nickel slag as raw material. The addition of a proper amount of nickel slag reduces the content of f-CaO in clinker and promotes the uniform, dense growth of grains in the clinker. When desulfurized gypsum is used as calcium raw material to mix with clinker, the content of f-CaO in clinker increases, which is not conducive to the preparation of clinker. (2) The optimal process for preparing road Portland cement with nickel slag is: the contents of nickel slag, limestone, fly ash, steel slag, desulfurized gypsum, and calcium fluoride (weight percentage) are 14%, 74%, 4%, 7%, 0.6% and 0.4%, respectively; the calcination temperature is 1350 °C and the heat preservation time is 60 min. The f-CaO content in the clinker prepared with this process is 0.22%. The 3-day compressive and bending strengths of the prepared cement paste are 21.9 MPa and 6.9 MPa, respectively. The 28-day values are 52.4 MPa and 14.5 MPa, respectively. The strength grade reaches the 42.5 grade. The amount of wear in the 28day hydration age is 2.1 kg/m2. (3) Magnesium in nickel slag mainly exists in the form of (Mg, Fe)2SiO4, MgSiO3, and Ca2Mg (SiO7). After calcination, it exists in the clinker in the forms of CaMgSi2O6, Mg2Si5Al4O18 and MgO, as well as Mg(OH)2 after hydration. Conflict of interest The authors have no competing interests to declare.

Acknowledgment Authors acknowledge the support from National Natural Science Foundation of China, china (Grant No. 51572234) and Key R & D programs in Jiangsu, China (Grant No. BE2018101). References [1] Guang Jian Miao, Wu Qi Sheng, Liu Xiao Yan, Zou Xiao Tong, Hydrothermal synthesis of nickel slag aerated concrete and its hydration reaction, J. Mater. Sci. Eng. 34 (3) (2016) 421–426 (in Chinese). [2] Li Xiaoming, Shen Miao, Wang Chong, et al., Current situation and development of comprehensive utilization of nickel slag, Mater. Rev. 31 (3) (2017) 100–105 (in Chinese). [3] Liao Yan, Zhao Xiao, Qin Chao Mei, Environmental hidden threat characteristic and potential environment hazards of metallurgy and mining industry, Morden Mining 26 (8) (2010) 15–18 (in Chinese). [4] Y.F. Shen, W.Y. Xue, W. Li, et al., Selective recovery of nickel and cobalt from cobalt-enriched Ni–Cu matte by two-stage counter-current leaching, Sep. Purif. Technol. 60 (2) (2008) 113–119. [5] M. Baghalha, V.G. Papangelakis, W. Curlook, Factors affecting the leachability of Ni/Co/Cu slags at high temperature, Hydrometallurgy 85 (1) (2007) 42–52. [6] Y.C. Zhai, M.U. Wen-Ning, Y. Liu, et al., A green process for recovering nickel from nickeliferous laterite ores, Chin. J. Nonferrous Metals 20 (1) (2010) 65–70. [7] Ma Ming Sheng, Ni Wen, Wanng Ya Li, Crystallization kinetics and process of the glass-ceramic produced by nickel slag, J. Univ. Sci. Technol. Beijing 29 (2) (2007) 168–172 (in Chinese). [8] Z.J. Wang, W. Ni, Y. Jia, et al., Crystallization behavior of glass ceramics prepared from the mixture of nickel slag, blast furnace slag and quartz sand, J. Non-Crystalline Solids 356 (31) (2010) 1554–1558. [9] Zhang Wen Jun, Yu Li, Li Hong, et al., Research of preparing CMSA glassceramics with the nickel iron slag and fly ash, Bull. Chin. Ceramic Soc. 33 (12) (2014) 3359–3365. [10] Ma Ming Sheng, Ni Wen, Wanng Ya Li, et al., Crystallization behavior and linetics of TiO2 and Cr2O3 doped glass ceramics produced from nickel residue, J. Chin. Ceramic Soc. 37 (4) (2009) 609–615. [11] Y.C. Choi, S. Choi, Alkali–silica reactivity of cementitious materials using ferronickel slag fine aggregates produced in different cooling conditions, Constr. Build. Mater. 99 (2015) 279–287. [12] E. Dourdounis, V. Stivanakis, G.N. Angelopoulos, et al., High-alumina cement production from FeNi-ERF slag, limestone and diasporic bauxite, Cem. Concr. Res. 34 (6) (2004) 941–947. [13] Peng Hua, Study on comprehensive utilization of Nolanda Furnace Slags (Part II), Metal Mine (1) (2004) 62–66 (in Chinese). [14] Shan Chang Feng, Wang Jian, Fu Zhang Jin, et al., Study on application of nickel slag in cement concrete, Bull. Chin. Ceramic Soc. 31 (5) (2012) 1263–1268. [15] T. Yang, X. Yao, Z. Zhang, Geopolymer prepared with high-magnesium nickel slag: Characterization of properties and microstructure, Constr. Build. Mater. 59 (6) (2014) 188–194. [16] Wang Ya Jun, HuaSu Dong, Yao Xiao, Experiment on the non-burnt brick with nickel and blast furnace slag, New Build. Mater. 40 (6) (2013) 23–25 (in Chinese). [17] Gao Shu Jie, Ni Wen, Li Ke Qing, et al., Prepartion and hydrated mechanism of mine filling material of water-granulated secondary nickel slag, J. Chin. Ceramic Soc. 41 (5) (2013) 612–619. [18] Li Ke Qing, Feng Lin, Gao Shu Jie, Preparation of cementitious materials for backfilling by using nickel slag, Chin. J. Eng. (1) (2015) 1–6. [19] R.I. Iacobescu, G.N. Angelopoulos, P.T. Jones, et al., Ladle metallurgy stainless steel slag as a raw material in Ordinary Portland Cement production: a possibility for industrial symbiosis, J. Cleaner Prod. 112 (2016) 872–881. [20] R.I. Iacobescu, D. Koumpouri, Y. Pontikes, et al., Valorisation of electric arc furnace steel slag as raw material for low energy belite cements, J. Hazard. Mater. 196 (1) (2011) 287–294. [21] P.E. Tsakiridis, G.D. Papadimitriou, S. Tsivilis, et al., Utilization of steel slag for Portland cement clinker production, J. Hazard. Mater. 152 (2) (2008) 805–811. [22] I. Alp, H. Deveci, H. Süngün, Utilization of flotation wastes of copper slag as raw material in cement production, J. Hazard. Mater. 159 (2) (2008) 390–395. [23] C. Shi, C. Meyer, A. Behnood, Utilization of copper slag in cement and concrete, Resour. Conserv. Recycling 52 (10) (2008) 1115–1120. [24] L.I. Jin-Qing, J.Q. Zhu, Research on sintered cement clinker by using phosphorus slag as raw material, World Build. Mater. (2009). [25] D. Chen, L. Cheng, H. Feng, et al., Study on calcination of quality cement clinker by high addition phosphorous slag, Bull. Chin. Ceramic Soc. (2010). [26] C.J. Engelsen, Effect of mineralizers in cement production, SINTEF Building and Infrastructure, COIN – Concrete Innovation Center, Trondheim, Norway, 2007.