High-quality gypsum binders based on synthetic calcium sulfate dihydrate produced from industrial waste

Maksim Kamarou,Natalia Korob,Witold Kwapinski,Valentin Romanovski 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.100 No.-

Synthetic calcium sulfate dihydrate, obtained from sulfuric acid waste of chemical plants and waste of thefine fraction of limestone, is a potential source of gypsum-containing raw materials. We investigated theprocessing of synthetic calcium sulfate dihydrate from sulfuric acid waste to gypsum, high-strengthgypsum binder, and anhydrite. The effects of technological parameters on the strength indicators ofbinders were studied. It was found that the obtained samples of binders (based on synthetic gypsum)meet all standards and even exceed the performance of binders obtained from natural gypsum stone. Ourstudies show that synthetic gypsum is a promising gypsum-containing raw material for the production ofgypsum binders and can be a promising alternative to natural gypsum stone.

불산 무수석고와 플라이 애쉬를 첨가한 시멘트 페이스트의 유동성 및 응결특성

노재성,김도수,홍성수,임계규,임헌성 한국세라믹학회 1997 한국세라믹학회지 Vol.34 No.12

Four kids of powder admixtures(A, B, C, D) based on anhydrite were manufactured by mixing at a fixed rate of II-anhydrite, fly ash and active silica as an industrial by-product. Fluidity properties of cement paste such as mini-slump, apparent viscosity with elapsed time, as well as setting time of cement pastes of these admixtures substituted up to 11wt% of cement were compared to those of cement paste(SS) substisuted by marketed high-strength powder admixture(S). Among these powder admixtures, the fluidity of cement pastes(PA, PC) substituted by A and C powder admixtures manufactured from II-anhydrite and fly ash had an excellent property than that of cement paste substituted by marketed powder admixture and also a good fluidity-retention effect with elapsed time by adding of superplasticizer. The setting time of cement paste substituted by powder admixtures based on anhydrite slightly retarded than that of cement paste substituted by marketed powder admixture.

Alunite와 limestone의 혼합소성에서의 무수석고의 합성

김형석,안지환,김환,신강호,조동성,Kim, Hyung-Seok,Ahn, Ji-Whan,Kim, Hwan,Shin, Kang-Ho,Cho, Dong-Sung 한국결정성장학회 2001 한국결정성장학회지 Vol.11 No.5

명반석$[K_2SO_4$.$Al_2(SO_4)_3$.$4Al(OH)_3$]을 공기분위기에서 가열하면 500~$580^{\circ}C$에서 탈수되고, 580~$780^{\circ}C$에서 $SO_3$(g)가 발생되므로 석회석과 혼합소성하였을 때의 무수석고($CaSO_4$)의 합성특성을 조사하였다. 명반석의 열분해는 $CO_2$(g) 분압에 영향이 없으나, 석회석의 경우 공기 분위기에서는 약 $650^{\circ}C$부터 분해되지만 $CO_2$(g)의 포화 분위기에서는 약 $900^{\circ}C$부터 분해된다. 명반석과 석회석을 1:6의 몰비로 혼합한 후 공기 분위기와 $CO_2$(g) 포화분위기에서 $10^{\circ}C$/min의 속도로 $1000^{\circ}C$까지 가열하여 2시간 동안 소성하면 $550^{\circ}C$에서 무수석고가, $700^{\circ}C$에서 calciumlangbeinite($(2CaSO_4$.$K_2SO_4$)가, 800~$950^{\circ}C$에서 ha yne이 형성되며 이때 무수석고의 합성량은 각각 99.0%와 95.0% 정도였다. 공기 분위기에서 무수석고 합성량은 석회석의 입도(0.5mm 이하)에 관계없이 거의 일정하지만, $CO_2$(g)의 포화분위기에서는 석회석의 입도가 작아짐에 따라 증가된다. 그러므로 명반석과 석회석을 1:6의 몰비로 혼합 소성하면 1 몰의 ha yne과 1 몰의 calciumlangbeinite로 구성된 클링커가 합성가능하다. Alunite was dehydrated at 500~$580^{\circ}C$ and desulfurued at 580~$780^{\circ}C$ in air atmosphere. Therefore, this study was carried out to investigate the formation conditions of anhydrite ($CaCO_4$) when the mixtures of alunite $[K_2SO_4$.$Al_2(SO_4)_3$.$4Al(OH)_3$] and limestone ($CaCO_3$)were roasted. Alunite scarcely dected the partial pressures of $CO_2$(g), but limestone was bansformed into CaO at $650^{\circ}C$ in air and $900^{\circ}C$ in saturated $CO_2$(g), atmosphere, respectively. When the the mixtures of 1 mol of alunite and 6 rnol of limestone were roasted for 2 hours at lO00C in air and saturated $CO_2$(g), anhydrite was formed at $550^{\circ}C$ calciumlangbeinite, at $700^{\circ}C$and haiiyne, at 800~$950^{\circ}C$. The formation rate of anhydrite in air and saturated $CO_2$(g), was 99.0 % and 95.0 %, respectively. then the formation rate of anhydrite was not changed in air atmosphere but increased according to the decreasing of the particle size of limestone in saturated $CO_2$(g). Therefore, when the mixture of 1 mol of alunite and 6 rnol of limestone were roasted, the clinker composed of lmol of haiiync and 1 mol of calciumlangbeiilte can be manufactured

건설안전분야 : 알루미나 시멘트와 무수석고를 이용한 그라우트의 재료적 특성

홍기남 ( Ki Nam Hong ),정진영 ( Jin Yeong Jung ),한상훈 ( Sang Hoon Han ) 한국안전학회(구 한국산업안전학회) 2011 한국안전학회지 Vol.26 No.5

This paper presents the research results performed to develope the shrinkage-free grout with high early strength. Alumina cement and anhydrite were utilized as the expensive tool to gain the shrinkage-free grout. The compressive strength, length change, and ettringite formation of the grout were investigated with compressive test, length change test, and X-ray diffraction. The more anhydrite was added into the grout, the larger the early expansion of the grout. In addition, the more anhydrite formated the more ettringite. From this study, It was conformed that the grout mixture with shrinkage-free property and high early strength is the mixture with the ratio of alumina cement and anhydrite of 40:60 by weight.

고로슬래그미분말 및 무수석고를 활용한 PHC말뚝 콘크리트용 혼화재 개발

한천구,김종백,Han, Cheon-Goo,Kim, Jong-Baek 대한건축학회 2011 대한건축학회논문집 Vol.27 No.8

This study investigated the possibility of high performance admixture for Pretensioned spun high strength concrete pile(PHC) to mix blast furnace slag and anhydrite with several fineness and replace contents. The results were following. The results for compressive strength, workability and economical efficiency was profitable when 40 %/C blast furnace slag with 8000 $cm^2/g$ and 1.14~11.66 % of anhydrite was used. For the hydrate properties using blast furnace slag and anhydrite mixture, the strength revelation was high caused by latent hydraulicity reaction and filling up effect as XRD and thermal analysis. when the anhydrite used heavy, the strength was decline because of expansion by too much ettringite generation. The blast furnace slag with 8000 $cm^2/g$ and anhydrite mixture could be used as mineral admixture for PHC using autoclave curing method, and it was effective at standard curing method. For these results, it could be a high performance admixture for high durability and flowability concrete.

실리카흄 및 석고 혼입에 따른 천연수경성석회의 수화특성

문기연,최문관,조계홍,조진상,홍창우,권우택,안지환 한국자원공학회 2016 한국자원공학회지 Vol.53 No.6

In the present study, the effects of adding a inorganic admixture such as silica fume (SF) and anhydrite to natural hydraulic lime (NHL) on hydration properties were systematically investigated. NHL was produced using domestic low-grade limestone. The hydration properties of NHL pastes were then investigated as a function of the hydration time and mixing ratio of mineral admixture. Through an investigation of the hydration properties of NHL pastes mixed with SF and anhydrite, C-S-H compounds and CaCO3 were observed. According to adding anhydrite, the formation of C-S-H hydrates was slightly delayed, but CaCO3 was created more than other specimen. The compressive strength was increased by the mixing of the silica fume, and optimum mixing ratio was about 20%. The compressive strength was increased more higher than other mortars from curing 7 days by addition of anhydrite, it was increased to maximum 10.2 MPa at 28 days. 본 연구에서는 무기질 첨가재인 실리카 흄과 석고 첨가에 따른 천연수경성석회 (NHL)의 수화특성에 대해연구를 수행하였다. 연구에서 사용된 천연수경성석회는 국내 저품위 석회석을 활용하여 제조하였다. 천연수경성석회 페이스트의 수화특성은 무기질 첨가재의 혼합비 및 수화시간에 따라 조사되었다. 또한, EU 규격에 의한 방법으로모르타르를 제작하여 압축강도 측정을 실시하였다. 실리카 흄과 석고를 혼합하여 제조한 천연수경성석회 페이스트의 수화특성분석결과 실리카 흄과 Ca(OH)2와의 반응에 의해 생성된 칼슘실리케이트 수화물 및 Ca(OH)2의 탄산화반응에 의한 CaCO3가 관찰되었다. 석고 혼합에 따라 칼슘실리케이트 수화물 생성은 다소 지연되었으나 CaCO3가 더 많이 생성되었다. 압축강도 분석결과 실리카 흄 첨가에 따라 압축강도는 증가하였으며 적정 혼입율은 20% 정도였다. 석고 첨가에 따라 재령 7일부터 압축강도가 증가하여 재령 28일에서 최대 10.2 MPa까지 상승하였다.

고로슬래그미분말 및 무수석고를 활용한 PHC말뚝 콘크리트용 혼화재 개발

한천구(Han Cheon-Goo),김종백(Kim Jong-Baek) 대한건축학회 2011 大韓建築學會論文集 : 構造系 Vol.27 No.8

This study investigated the possibility of high performance admixture for Pretensioned spun high strength concrete pile(PHC) to mix blast furnace slag and anhydrite with several fineness and replace contents. The results were following. The results for compressive strength, workability and economical efficiency was profitable when 40 %/C blast furnace slag with 8000 ㎠/g and 1.14~11.66 % of anhydrite was used. For the hydrate properties using blast furnace slag and anhydrite mixture, the strength revelation was high caused by latent hydraulicity reaction and filling up effect as XRD and thermal analysis. when the anhydrite used heavy, the strength was decline because of expansion by too much ettringite generation. The blast furnace slag with 8000 ㎠/g and anhydrite mixture could be used as mineral admixture for PHC using autoclave curing method, and it was effective at standard curing method. For these results, it could be a high performance admixture for high durability and flowability concrete.

무수석고-고로슬래그계의 수화반응

송종택,고상열,노재성 한국세라믹학회 1997 한국세라믹학회지 Vol.34 No.8

In order to investigate the reaction in the system of anhydrite II-blast furnace slag, the paste hydration which made up with a liquid/solid ratio of 0.45 for 1, 3, 7, 14, 28days by the addition of accelerators to 10~30wt.% slag with natural gypsum calcined for 1hour at 500/$700^{\circ}C$ was studied by combined water determination, XRD, DTA, DSC and SEM. As a result of this experiment, it was found that hydration rate was faster in the system calcined at 50$0^{\circ}C$. Therefore the anhydrite was converted to calcium sulfate dihydrate in the hydration for 1day but the slag was not almost reacted. For the gypsum calcined at $700^{\circ}C$, the hydraton rate in the system of K2SO4 addition was faster than others in the earier period, but the activated effect of the system of Al2(SO4)3 addition was regarded as the highest over 3days. As the amount of slag was increased, they dydration rate was delayed and ettringite was observed in the case of K2SO4 system. However both Al2(SO4)3 and AlK(SO4)2 systems showed calcium sulfate dhydrate only as hydrated products.

고유동화제와 시멘트 혼화용 무기미분체가 첨가된 시멘트 페이스트의 유동성 변화

김도수,정흥호,박병배,노재성 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.8

Effects of the dosage change, from 0 to 2.0 wt% based on cement weight, of naphthalenic (NSF) and polycarboxylic(NT-2) superplasticizers, on the fluidity of cement paste substituted by 10 wt% II-anhydrite and fly ash respectively as well as II-anhydrite and fly ash itself were investigated. Dispersion properties between particles in suspension were investigated by zeta potential test. Initial fluidity and slump loss in the paste system were observed through mini-slump and apparent viscosity changes with elapsed time. Zeta potential on the particle surface was a tendency to increase according to increasing of NSF dosage. Especially, zeta potential of fly ash has the highest value among all particles equivalent to NSF dosage. In the fluidity of cement paste substituted by inorganic particles, the specimen with substitution of 10 wt% II-anhydrite and fly ash for cement was more effective than cement itself to improve initial fluidity and retain stable fluidity of cement paste. In addition, effect of NT-2 and NSF to improve the fluidity of cement paste, addition of 1.0 wt% NT-2 was more effective than 1.5wt% NSF.

무수석고 함량이 고로슬래그 미분말을 대량 활용한 콘크리트 특성에 미치는 영향

문규돈(Moon, Gyu-Don),김주형(Kim, Joo-Hyung),조영근(Cho, Young-Keun),최영철(Choi, Young-Cheol) 한국건설순환자원학회 2014 한국건설순환자원학회 논문집 Vol.2 No.3

온실가스 저감 및 자원활용 목적으로 고로슬래그 미분말을 다량으로 활용한 콘크리트에 대한 연구가 활발히 진행되고 있으나, 조기강도 및 내구성능 확보에 어려움이 있다. 따라서, 본 연구에서는 무수석고 함량(0%, 4%, 6%, 8%, 10%)에 따라 고로슬래그 미분말을 대량 활용한 콘크리트의 수화, 강도발현, 크리프, 탄산화, 건조수축 특성을 분석하였다. 무수석고를 바인더의 4~6% 수준으로 치환할 경우 고로슬래그 미분말 대량 활용 콘크리트의 가장 취약점인 초기강도 발현을 보완할 수 있으며, 내구성 측면에서도 보통 포틀랜드 시멘트를 사용한 콘크리트와 유사한 성능을 발현하는 것을 알 수 있었다. 반면, 무수석고를 8% 이상 활용할 경우 초기강도 증진 효과가 미흡한 결과를 나타냈다. High volume slag concrete is attracting new attention and are thought to have promising potential for industrial applications, partly due to the climate debate, but especially due to their very low heat of hydration and their good durability in chemically aggressive environments. However, High volume slag concretes tend to have slower strength development especially. In this study, the effect of anhydrite () on the mechanical and durability performance of high volume slag concrete were investigated. The main variables were anhydrite contents (0, 4, 6, 8, 10%). Test results show that 4~8% anhydrite concrete have improved engineering properties (hydration, compressive strength, shrinkage, creep, carbonation) as control concrete at early ages.