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Investigations of anhydrite in CFBC fly ash as cement

Mar 01, 2013 In Portland cement, usually natural gypsum is added to act as an effective retarder controlling the hydration of the C 3 A phase . Tzouvalas et al. have investigated the replacement of natural gypsum with natural anhydrite and by-product gypsum,. They found that natural anhydrite and FGD gypsum can be suitable alternatives to gypsum based on

(PDF) Analysis of anhydrite's effects on quality of cement

The experimental data conclude that natural anhydrite can be a very efficient retarder of the setting of cement, with no significant change in the physicomechanical properties of the hardened

Investigations of anhydrite in CFBC fly ash as cement

Experimental results indicated that anhydrite in CFBC ash can be used as an efficient setting retarder but lead to lower mortar strength. The effect is harmless to volume stability of cement paste with appropriate anhydrite addition. Compared with natural gypsum, anhydrite in CFBC ash makes ettringite formation slower and more transformable.

Alternative Calcium Sulfate-Bearing Materials as Cement

Oct 13, 2020 The experimental data conclude that natural anhydrite can be a very efficient retarder of the setting of cement, with no significant change in the physicomechanical properties of the hardened

Analysis of anhydrite gypsum effects on quality of cement

justify this, retarder raw materials are used. In cement industry, natural gypsum (CaSO 4 ·2H 2 O) is the most effective raw material for this purpose. In the natural gypsum sources, anhydrite gypsum can often be encountered, so its effect on cement’s quality parameters must be focused on [1-3].

Alternative calcium sulfate-bearing materials as cement

Nov 01, 2004 The rapid hardening of cement pastes due to the vivid reaction of C 3 A with water is usually prevented by adding a substance acting as a retarder of the setting of cement. Cement industry has been using natural gypsum (CaSO 4) as a first choice material. Natural gypsum and natural anhydrite coexist in the stocks.

ALTERNATIVE CALCIUM SULFATE-BEARING MATERIALS AS

The rapid hardening of cement pastes due to the vivid reaction of C3A with water is usually prevented by adding a substance that acts as a retarder of the setting of cement. Substances that regulate the setting of cement, such as natural anhydrite, have attracted significant scientific interest during the past years.

gypsum completely replace natural gypsum as cement retarder

gypsum completely replace natural gypsum as cement retarder. There are forty years of manufacturing history, with three major production bases,over 160 senior R&D engineers and 600+ large and medium-sized digital processing equipment, The first-line technicians and professional after-sales service personnel up to 2,300+ and 200+ respectively.Introducing advanced technology and craftsmanship

Use of inorganic setting retarders in cement industry

The use of calcium sulfate-bearing retarder materials such as natural gypsum, anhydrite and flue-gas desulfurization (FGD) gypsum in cement industry was investigated by Papageorgiou et al. [20

Use of inorganic setting retarders in cement industry

Feb 01, 2005 1. Introduction. The most common cement setting retarder used in industry is natural gypsum, which is primarily a dihydrated product of calcium sulfate (CaSO 4 · 2H 2 O). The need for gypsum in cement increases with increasing amount of C 3 A and alkalies in the clinker and the fineness of the cement,, .Gypsum also promotes cement strength at an optimum content value .

(PDF) Analysis of anhydrite's effects on quality of cement

The experimental data conclude that natural anhydrite can be a very efficient retarder of the setting of cement, with no significant change in the physicomechanical properties of the hardened

Analysis of anhydrite gypsum effects on quality of cement

justify this, retarder raw materials are used. In cement industry, natural gypsum (CaSO 4 ·2H 2 O) is the most effective raw material for this purpose. In the natural gypsum sources, anhydrite gypsum can often be encountered, so its effect on cement’s quality parameters must be focused on [1-3].

Use of inorganic setting retarders in cement industry

The use of calcium sulfate-bearing retarder materials such as natural gypsum, anhydrite and flue-gas desulfurization (FGD) gypsum in cement industry was investigated by Papageorgiou et al. [20

Study of early hydration of cement pastes containing

The experimental data conclude that natural anhydrite can be a very efficient retarder of the setting of cement, with no significant change in the physicomechanical properties of the hardened

gypsum completely replace natural gypsum as cement retarder

gypsum completely replace natural gypsum as cement retarder. There are forty years of manufacturing history, with three major production bases,over 160 senior R&D engineers and 600+ large and medium-sized digital processing equipment, The first-line technicians and professional after-sales service personnel up to 2,300+ and 200+ respectively.Introducing advanced technology and craftsmanship

Alternative calcium sulfate-bearing materials as cement

The hydration process of cement pastes is of great importance to the physicomechanical properties of the hardened material. Thus, substances that regulate the setting of cement, such as natural anhydrite, have attracted significant scientific interest during the past years. This paper briefly describes the results of utilization of natural anhydrite in cement pastes of CEM-I and CEM-II types.

US4098613A Basic oil well cement Google Patents

A versatile hydraulic basic oil well cement, compatible with retarders and most common field additives and able to perform its intended function over a wide variety of downhole conditions, particularly temperature and pressure, comprises a common moderate or high sulfate resistant clinker and a weight ratio of calcium sulfate hemihydrate to insoluble anhydrite of 20:80 to 45:55.

(PDF) Purification of South African phosphogypsum for use

Purification of South African phosphogypsum for use as Portland cement retarder by a combined thermal and sulphuric acid treatment method replace natural gypsum in Portland cement

Retarders for Concrete Mechanism, Types and Effects on

Retarders for concrete are used to delay the initial setting time of the concrete upto an hour. They are generally used in the hot weather condition to counter the rapid hardening due to high temperature, thus allowing the time for mixing, transporting and placing. Retarders also acts as water reducers. In this article we discuss

gypsum replacement anhydrite in cement grinding

gypsum replacement anhydrite in cement grinding . Market of Second Hand Concrete Batching Plants For Sale In MalaysiaDevelopment of Second Hand Concrete Batching Plants are to large-scale, automated, intelligen. Raw Complex Gold Ore Processing Machine.

Calcium sulfate Wikipedia

Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO 4 and related hydrates.In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant.One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum.It has many uses in industry. All forms are white solids that are poorly soluble in water.

Natural Gypsum Price Buy Gypsum Stone Price,Anhydrite

Natural Gypsum Price,Find Complete Details about Natural Gypsum Price,Gypsum Stone Price,Anhydrite Gypsum,Natural Gypsum Stone from Gypsum Powder Supplier or Manufacturer-Qingdao Shiji Yongda Saltbuild-Up Import And Export Co., Ltd. It can be used for cement retarder, gypsum building products, model making, medical food additive, sulfuric

Class H Oil Well Cement Hydration at Elevated Temperatures

In situ powder X-ray diffraction was used to examine the hydration of API Class H cement slurries, with a water-to-cement ratio of 0.394, at 66, 93, 121, and 177 °C under autogenous pressure in the presence of varying amounts of the additives tartaric acid, modified lignosulfonate, and AMPS (2-acrylamido-2-methylpropanesulfonic acid) copolymer. All of these retarding agents inhibited the

US3147129A Sulfoaluminate cement Google Patents

US3147129A US58618A US5861860A US3147129A US 3147129 A US3147129 A US 3147129A US 58618 A US58618 A US 58618A US 5861860 A US5861860 A US 5861860A US 3147129 A US3147129 A US 3147129A Authority US United States Prior art keywords cement slag sulfoaluminate anhydrite additive Prior art date 1960-09-27 Legal status (The legal status is an assumption and is not a legal

Use of inorganic setting retarders in cement industry

The use of calcium sulfate-bearing retarder materials such as natural gypsum, anhydrite and flue-gas desulfurization (FGD) gypsum in cement industry was investigated by Papageorgiou et al. [20

Calcium Sulfate Anhydrite, Natural Anhydrite Oreworld Trade

Calcium Sulfate Anhydrite work as cement setting speed agent. It is subsidiary adjusting agent for sulphate aluminate series special engineering materials. It can be used in cement based self leveling, rush repair materials, non-shrinkage grout, rapid setting and high strength cement product, cement decorative products and special mortar.

Study of early hydration of cement pastes containing

The experimental data conclude that natural anhydrite can be a very efficient retarder of the setting of cement, with no significant change in the physicomechanical properties of the hardened

US3954489A Method for retarding the setting time of

This invention relates to a method for retarding the setting time of rapid hardening cement which comprises adding a boric compound to cement manufactured by adding insoluble anhydrite to clinker powder containing 11CaO.7Al 2 O 3 .CaX 2 or adding the clinker to insoluble anhydrite and intergrinding the mixture, and a method for still more retarding the setting time of rapid hardening cement

RESEARCHES INTO POSSIBILITY OF APPLICATION OF

natural anhydrite to replace Portland cement in certain fields of application. As a sulphate retarder of setting, anhy-drite can be used for production of common cement. For these purposes, of use is also the top layer of deposit consist-ing of anhydrite and gypsum rock mix. The investigations showed that anhydrite powder of high whiteness (> 90 %)

Calcium sulfate Wikipedia

Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO 4 and related hydrates.In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant.One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum.It has many uses in industry. All forms are white solids that are poorly soluble in water.

EVALUATION OF ALTERNATIVE SETTING RETARDERS IN CEMENT

Abstract: The constant use of natural gypsum as setting retarder in cement has led to the reduction of its high purity stock in Greece. The aim of this project was to investigate the possible displacement of natural gypsum (CaSO 4 ·2H 2 O) in cement (CEM I and CEM II types) with alternative setting retarders such as: i) anhydrite, ii) phosphogypsum and iii) FGD gypsum.

Cement Hydration Inhibition with Sucrose, Tartaric Acid

Sep 07, 2006 The reaction of the cement retarders tartaric acid, sucrose, and lignosulfonate with tricalcium silicate (C3S), tricalcium aluminate (C3A), and C3A/gypsum have been studied by 27Al and 29Si MAS NMR spectroscopy, SEM, XRD, and XPS to gain an understanding of the effect on the individual minerals prior to studying a typical sample of portland cement.

US2937926A Method of preparing synthetic anhydrite

US2937926A US645905A US64590557A US2937926A US 2937926 A US2937926 A US 2937926A US 645905 A US645905 A US 645905A US 64590557 A US64590557 A US 64590557A US 2937926 A US2937926 A US 2937926A Authority US United States Prior art keywords anhydrite neutralization sulfuric acid water percent Prior art date 1956-12-29 Legal status (The legal status is an assumption

Class H Oil Well Cement Hydration at Elevated Temperatures

In situ powder X-ray diffraction was used to examine the hydration of API Class H cement slurries, with a water-to-cement ratio of 0.394, at 66, 93, 121, and 177 °C under autogenous pressure in the presence of varying amounts of the additives tartaric acid, modified lignosulfonate, and AMPS (2-acrylamido-2-methylpropanesulfonic acid) copolymer. All of these retarding agents inhibited the

gypsum replacement anhydrite in cement grinding

gypsum replacement anhydrite in cement grinding . Market of Second Hand Concrete Batching Plants For Sale In MalaysiaDevelopment of Second Hand Concrete Batching Plants are to large-scale, automated, intelligen. Raw Complex Gold Ore Processing Machine.

US3147129A Sulfoaluminate cement Google Patents

US3147129A US58618A US5861860A US3147129A US 3147129 A US3147129 A US 3147129A US 58618 A US58618 A US 58618A US 5861860 A US5861860 A US 5861860A US 3147129 A US3147129 A US 3147129A Authority US United States Prior art keywords cement slag sulfoaluminate anhydrite additive Prior art date 1960-09-27 Legal status (The legal status is an assumption and is not a legal

US3819389A Process for manufacturing a rapid hardening

US3819389A US00309805A US30980572A US3819389A US 3819389 A US3819389 A US 3819389A US 00309805 A US00309805 A US 00309805A US 30980572 A US30980572 A US 30980572A US 3819389 A US3819389 A US 3819389A Authority US United States Prior art keywords clinker anhydrite carbonate cement mixture Prior art date 1971-11-26 Legal status (The legal status is an assumption

Utilization of neutralized spent sulfuric acid pickle

cement mixture results in an appropriate initial set time of the cement and contributes to its final strength. Waste under investigation was introduced to the cement mixture as a set retarder to ensure the proper initial setting time. Waste gypsum was a substitute of a natural gypsum. Fig. 1 Satellite image of lagoons with deposited waste