scholarly journals Receiving Portland Cement from Technogenic Raw Materials of South Kazakhstan

2019 ◽  
Vol 21 (4) ◽  
pp. 333 ◽  
Author(s):  
N.N. Zhanikulov ◽  
T.M. Khudyakova ◽  
B.T. Taimassov ◽  
B.K. Sarsenbayev ◽  
M.S. Dauletiarov ◽  
...  

A method of producing portland cement using the wastes of enrichment of polymetallic ores of "Achpolymetal" (Kentau, Kazakhstan) in the amount of 0.5 to 2.5% as a mineralizing additive in the raw mixture is proposed. This allows the clinker to be produced at a lower temperature (1300–1350 °C), resulting in lower fuel consumption and higher furnace productivity. The experimental clinker is better subjected to grinding, the electric power consumption for grinding cement decreases, the grinding bodies of cement mills decrease. In the waste, there are catalytic and modifying elements. Studies have shown that in the no-added raw mix the clinker formation processes are completed at 1450 °C. When 0.5 to 2.0% of the tailings are introduced, the complete binding of CaO is completed at 1400 °C, with the addition of 2.5% of tailings, lime binding is completed at 1300 or 150 °C lower than in the control non-additive raw mixture. In clinkers, only 1.09–1.32 % of free lime remains. The strength of cement when introduced into the raw mix from 0.5 to 2.0% of barite waste is increased. The compressive strength at 28 days of age for cement with an optimum dosage of 1‒2% of the tail increases from 414 kg/cm2 to 430‒432 kg/cm2 or by 3.9‒4.3%. Similarly, the strength of steamed samples increases by 4.7‒5.7%.

2021 ◽  
Vol 4 (2) ◽  
pp. 12-18
Author(s):  
D.A. Tolypin ◽  
N. Tolypina

the article proposes a rational method for processing 3D printing concrete scrap using vibration equipment, which allows obtaining a multicomponent building material with minimal electricity consumption. As a crite-rion for the degree of grinding of concrete scrap, it is proposed to use the specific surface area of the finely dispersed part of concrete scrap, which should correspond to 400-500 m2/kg. The possibility of reusing the resulting product instead of the traditional fine aggregate of quartz sand is shown. It was found that the con-crete scrap without the addition of Portland cement hardens, reaching up to 48% of the compressive strength of the control samples by 28 days. When 10% of the binder CEM I 42.5 N was added to the concrete scrap processing product, the compressive strength of fine-grained concrete increased by 106.6%, and 20% of Portland cement - by 112.2 %, compared to the strength of control samples of a similar composition on tra-ditional quartz sand after 28 days of hardening. It is noted that this is primarily due to the weak contact zone of quartz sand and the cement matrix of concrete. The use of the product of processing concrete scrap al-lows obtaining building composites based on it with the complete exclusion of natural raw materials


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Wang ◽  
Geng Yao ◽  
Xiangnan Zhu ◽  
Junxiang Wang ◽  
Peng Wu ◽  
...  

The disposal of gold ore tailings (GTs) has been a very difficult problem for a long time. Thus, this study explored a new approach to the management of GTs by preparing Portland cement. Physical properties, reaction mechanisms, and hydration product types of cement prepared with GTs (C-GTs) and ordinary Portland cement (C-SS) were compared. X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscope energy-dispersive spectroscopy (SEM-EDS) analysis techniques were used to study the mineralogical phases of the clinker and raw materials, hydration product types, and microtopography. The consistency, setting time, flexural strength and compressive strength values of the cement samples (C-GTs and C-SS), and burnability of the raw materials were also studied. The burnability analysis indicated that GTs provided a higher reactivity. The XRD results showed that the clinker phases of the C-GTs were C3S, C2S, C3A, and C4AF. The XRD, TG, and SEM-EDS results showed that the hydration products were flaky calcium hydroxide, rod-shaped ettringite, and granular C-S-H gels. Its compressive strength and flexural strength were, respectively, 30.4 MPa and 6.1 MPa at the curing age of 3 days and 59.1 MPa and 9.8 MPa at the curing age of 28 days, which were slightly higher than those of the C-SS. Furthermore, the results showed that the consistency, initial setting time, and final setting time for the two kinds of cement were similar, which further suggested that GTs could be used to prepare Portland cement.


2013 ◽  
Vol 327 ◽  
pp. 40-43
Author(s):  
Xiao Long Li ◽  
Guo Zhong Li

The ordinary portland cement was used to prepare foamed cement insulation materials by physical foaming method. The influence of different process of fiber added to the foamed cement insulation materials on its performance was studied and the optimum mix ratio of raw materials was determined. The results showed that the glass fire could be evenly dispersed in the slurry by dry adding technology and got better enhanced effect. When the dosage of glass fire was 0.9%, the performance of the foamed cement material as follows: dry density of 318 kg/m3, 3d flexural strength of 0.61MPa, 3d compressive strength of 1.05MPa, thermal conductivity of 0.065W/(m·k). The reinforce mechanism of glass fire was explored.


Author(s):  
Laura Sele ◽  
Diana Bajare ◽  
Girts Bumanis ◽  
Laura Dembovska

<p>According to research conducted in last 25 years, alkali activated binders have been considered as one of the most progressive alternative binders, which can effectively replace Portland cement. Production of alkali activated binders differs from the Portland cement production and is associated with lower CO2 emissions. The use of recycled industrial by-products and wastes is also possible, what corresponds to the future guidelines and principles of sustainable binder production in the world.<br />The aim of this study was to create innovative alkali activated binders by using secondary raw materials, which will be different from the ones described in the scientific literature – alkali activated binders with porous structure. Raw materials used for the binders were metakaolin containing waste, waste from aluminium scrap recycling factory and recycled lead-silicate glass; solid contents were activated with modified sodium silicate solution with an addition of sodium hydroxide.<br />The physical properties of alkali activated binders, such as density, water absorption, open and total porosity, were determined and flexural and compressive strength of hardened alkali-activated binders were tested at the age of 28 days. Durability was examined by sulphate resistance test, which was performed according to SIA 262/1, appendix D: applicability and relevance for use in practice. 40x40x160 mm prismatic specimens were used for expansion measurement and determination of compressive strength. <br />The open porosity of obtained materials was up to 45%, density from 380 to 1720 kg/m3, compressive strength up to 29,8 MPa, water absorption 6 – 114 wt.%. After analysing the results from the sulphate test it was concluded that glass additive reduced the alkali activated binder resistance to sulphate attack.</p>


Author(s):  
М.Ш. Саламанова ◽  
С.А. Алиев ◽  
Р.С.-А. Муртазаева

В процессе обжига портландцементного клинкера в электрофильтрах вращающихся печей скапливается большое количество пыли, как клинкерной, так и аспирационной, поэтому рациональное использование этих продуктов, содержащих определенную долю полноценного сырьевого ресурса, является актуальной задачей индустрии цемента. В данной работе представлены результаты исследований цементной пыли, проведен энергодисперсионный и сравнительный анализ исследуемых порошков, а также приводится возможный способ утилизации цементной пыли для получения бесклинкерных цементов щелочной активации и бетонов на их основе. Разработанные рецептуры бесклинкерных вяжущих с применением отходов цементной промышленности и натриевого жидкостекольного затворителя позволят получать менее затратные, прочные и долговечные композиты, которые позволят частично заменять традиционный бетон на дорогом портландцементе. Работа выполнена в рамках исследований по реализации научного проекта 1848200001 Высококачественные бетоны с повышенными эксплуатационными свойствами на основе местного природного и техногенного сырья , получившего поддержку Российского фонда фундаментальных исследований (РФФИ). In the process of firing Portland cement clinker in electrostatic precipitators, in rotary kilns, a large amount of harmful substances, both clinker and aspiration, accumulates, therefore rational use of these products leads to certain shares of a fullfledged river resource, which are derived from industrial cement. It should be noted that the reuse of dust electrostatic precipitators is impossible. The basis for obtaining durable and more resourceefficient composites is based on modern technological methods that contribute to the improvement of technical and physicomechanical properties, with the integrated application of technogenic raw materials and liquid sodium binder. The developed clinkerfree binder formulations using the cement industry wastes and sodiumbased sludge glass will make it possible to produce less expensive, durable, and durable composites that will partially replace traditional concrete with expensive portland cement.


2021 ◽  
Vol 340 ◽  
pp. 01004
Author(s):  
Fedor Gorbunov ◽  
Lilia Berdnikova ◽  
Victor Bulgakov ◽  
Alexandra Fadina ◽  
Andrey Lapin

The possibility of using technogenic raw materials – the screening of crushed stone with the addition of cullet based on a silicate binder for the production of construction materials for structural purposes is studied. By varying the processing temperature, it was possible to increase the softening coefficient of the products and to achieve the pH neutrality of their pore liquid. Products processed at a temperature of 500700 °C have the following performance characteristics: the compressive strength 16.6-31.4 MPa, the bendingstrength 3.4-5.9 MPa.


Author(s):  
S. A. Aliev ◽  
R. S.-A. Murtazayevа ◽  
M. Sh. Salamanova

Objectives In the process of firing Portland cement clinker in electrostatic precipitators, in rotary kilns, a large amount of harmful substances, both clinker and aspiration, accumulates, therefore rational use of these products leads to certain shares of a full-fledged river resource, which are derived from industrial cement. It should be noted that the reuse of dust electrostatic precipitators is impossible.Method The basis for obtaining durable and more resource-efficient composites is based on modern technological methods that contribute to the improvement of technical and physicomechanical properties, with the integrated application of technogenic raw materials and liquid sodium binder.Result The basis for obtaining durable and more resource-efficient composites is based on modern technological methods that contribute to the improvement of technical and physicomechanical properties, with the integrated application of technogenic raw materials and liquid sodium binder.Conclusion The developed clinker-free binder formulations using the cement industry wastes and sodium-based sludge glass will make it possible to produce less expensive, durable, and durable composites that will partially replace traditional concrete with expensive portland cement. 


2014 ◽  
Vol 1000 ◽  
pp. 43-46
Author(s):  
Iva Kolářová ◽  
Pavel Šiler ◽  
František Šoukal

The aim of this work was to investigate the effect of addition of elements present in secondary raw materials on the hydration and compressive strength of Portland cement. Ordinary Portland cement (OPC) has been used to solidify hazardous waste for about 25 years and the effect of waste components on the hydraulic activity is an interesting object for the research. In this study Zn nitrate, chloride and oxide were added to Portland cement. The concentrations of 0.1 and 1.0 weight percent of zinc in cement were tested. After 1, 7 and 28 days the compressive strength was reduced or similar by the addition of zinc in comparison with pure cement. This difference is probably due to a delay in tricalcium silicate hydration as shown by isothermal calorimetry.


2012 ◽  
Vol 730-732 ◽  
pp. 94-99 ◽  
Author(s):  
Maria Margarida Rolim Augusto Lima ◽  
L.F.C. Braz ◽  
Regina da Conceição Corredeira Monteiro ◽  
J.P. Veiga

Phosphogypsum (PG) is a pollutant residue resulting from the production of phosphoric acid in the phosphated fertilizers industry. About 180 millions of tons of PG are generated worldwide per year, which originates storage problems because of the environmental restrictions and the high costs of storage spaces. Taking into account the mineralizer properties of PG it has been studied a way to valorize this residue as an alternative material in the production of Portland cement clinker. The PG and the raw-materials (limestone, marl, sand and iron oxide) were chemical, mineralogical and thermally characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and differential thermal analysis and termogravimetric analysis (DTA/TGA). After milling, the phosphogypsum was mixed with the raw-materials in different amounts up to 10% weight. The raw mixtures were submitted to two types of firing schedules, heating up to 1500°C without any holding time or heating up to 1350°C and holding for 20 minutes. After firing, the clinkers were analyzed by optical microscopy, milled and characterized in terms of chemical and mineralogical compositions. The clinkers were used to produce cement mortar according to NP EN 196-1 standard. The resultant test specimens were mechanically tested at 2 and 28 days according to the same standard. The obtained results show a reduction of about 140°C in the clinkerization temperature, when a raw mixture with 5% phosphogypsum was used. Standard clinkers, without phosphogypsum addition, which were fired at 1500°C, originated test specimens with a compressive strength of 48.1MPa at 28 days. Test specimens produced with clinker containing 5% phosphogypsum present higher compressive strength values at 28 days, being 55.1MPa for clinkers produced at 1500°C, and 49.4 MPa for clinkers produced at 1350°C.


2018 ◽  
Vol 12 (2) ◽  
pp. 265
Author(s):  
Tjokorde Walmiki Samadhi ◽  
Pambudi Pajar Pratama

SYNTHESIS OF GEOPOLYMER FROM METAKAOLIN AND FLY ASH.Geopolymer is an inorganic polymer produced by reacting aluminosilicate solids with a strongly basic activator. Geopolymers can be applied as construction adhesives, replacing ordinary Portland cement. Geopolymerization reaction may occur near room temperatures, implying less energy consumption compared to Portland cement. A variety of inorganic wastes may be selected as the aluminosilicate reactant, which makes geopolymer useful in managing solid wastes. This study builds upon a previous preliminary study, which has proven the technical feasibility of using domestically available raw materials to produce geopolymers. This particular study evaluates the resistance of geopolymers to high temperature, which simulates fire in civil structures. A 24 full factorial design experiment has been undertaken to evaluate the impact of aluminosilicate type (metakaolin and fly ash), base activator type (NaOH and KOH), curing temperature (60 and 80 oC), and heating at 800oC for 2 hours on the compressive strength of the mortar. Combining fly ash, KOH, and higher curing temperature produces the highest compressive strength. Heating at 800 oC reduces the strength of metakaolin geopolymer by inducing crystallization which consumes the geopolymer gel phase, but improves the strength of the fly ash geopolymer mortar by increasing the cohesion of fly ash particles.Keywords: geopolymer, mortar, OPC, compressive strength, heat resistance AbstrakGeopolimer merupakan polimer anorganik yang tersusun oleh rantai-rantai atom Al, Si, dan O, dan dihasilkan melalui reaksi padatan aluminosilikat dengan aktivator basa kuat. Geopolimer dapat digunakan sebagai bahan perekat untuk konstruksi sebagai pengganti semen Portland. Reaksi geopolimerisasi dapat berlangsung di sekitar temperatur kamar, sehingga konsumsi energi produksi geopolimer lebih rendah daripada OPC. Berbagai limbah anorganik dapat digunakan sebagai reaktan aluminosilikat, sehingga geopolimer juga berguna dalam pengelolaan limbah padat. Kajian ini merupakan kelanjutan dari kajian awal yang membuktikan kelayakan teknis pemanfaatan bahan-bahan dalam negeri untuk sintesis geopolimer. Kajian ini mengevaluasi daya tahan geopolimer terhadap temperatur tinggi, yang mencerminkan kejadian kebakaran pada struktur bangunan sipil. Suatu percobaan faktorial 24 dijalankan untuk mengevaluasi pengaruh jenis bahan aluminosilikat (metakaolin dan abu terbang), jenis aktivator basa (NaOH dan KOH), temperatur pematangan mortar geopolimer (60 dan 80 oC), serta pemanasan pada 800 oC selama 2 jam terhadap kuat tekan mortar geopolimer. Kombinasi abu terbang, aktivator KOH, serta temperatur pematangan 80 oC memberikan kuat tekan  tertinggi, yang bahkan lebih tinggi daripada mortar OPC. Pemanasan pada 800 oC merusak struktur jaringan geopolimer metakaolin dengan mendorong kristalisasi yang mengkonsumsi fasa gel geopolimer, sementara justru memperkuat geopolimer abu terbang dengan meningkatkan kohesi antara partikel-partikel abu terbang.Kata kunci: geopolimer, mortar, OPC, kuat tekan, daya tahan panas


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