آخرین محصولات

Effect of geopolymer cement on microstructure, …

The effect of geopolymer cement on the compressive strength and resistance to sulphuric acid of concrete made with type 10 and type 50E cements was studied. Hydration products and microstructure ...

(PDF) Effect of Temperature and Acidity of Sulfuric Acid on Concrete …

As the gypsum material is 65 eroded, the concrete loses its binder and begins to spall, exposing new surfaces. ... 0.2% and 0.05% sulphuric acid solution. Most research on the resistance of concrete to 78 sulphuric acid attack has considered the effectiveness of the change in concrete mix design on 79 concrete resistivity (Bassuoni and Nehdi ...

EP0004568A1

This invention relates to the production of sulphuric acid from phospho-gypsum and/or natural gypsum. More particularly it relates to a new method for production of sulphur dioxide ... Process for the preparation …

Sulfuric Acid from Phosphogypsum, DMC-FIPR Process

Current established technology for making sulfuric acid (H 2 SO 4) and cement clinker by-product from phosphogypsum (such as the OSW process developed by Chemie Linz, Austria) is not economic when compared with sulfur burning.It has only been applied in a few locations (Austria, China, and South Africa) where special circumstances prevail.

Sulphuric Acid Resistance of Slag Geopolymer Concrete

This work is an experimental study on sulphuric acid resistance of geopolymer concrete. The main variables considered throughout the research program were fly ash content from 0.0 to 40% and silica fume content as replacement of quenched slag in addition to sodium hydroxide molarity and added water content. These variables …

Zimbabwe Phosphate Industries

Gypsum is produced at ZimPhos as a byproduct of phosphoric acid manufacture and is used for agricultural purposes as well as for cement, plaster and ceiling board manufacture. ... "For the sulphuric acid plant we are trying to raise another US$10 million to finish it. "The project has been stretched out overtime, we should have finished ...

Test Methods for Resistance of Concrete to Sulfate Attack

The sulfuric acid first reacts with the calcium hydroxide in the concrete to form gypsum. This reaction is associated with an increase in volume which will cause deterioration. However damage is also caused by the reaction between the formed gypsum crystals and the C 3 A minerals, which leads …

Severe Sulfuric Acid Attack on Self-Compacting Concrete …

The sulfuric acid reacts first with the calcium hydroxide (CH) to precipitate gypsum (CaSO 4 2H 2 O) on and below the concrete surface, which can induce tensile …

Sulphuric acid resistance of ground ferronickel slag …

The sulphuric acid attack is a common deterioration mechanism that is used to investigate the acid resistance of concrete. A structure can be exposed to aggressive sulphuric acid in different ways. Industrial effluent, ground water and acid rains are the major sources of sulphuric acid that can cause deterioration of concrete …

Response of Oyster Shell Ash Blended Cement Concrete …

aluminate hydrate to form ettringite and gypsum had been reported by (Nabil, 2016; Salah, 2007). They concluded that these products (ettringite and gypsum) lead to cracking, deterioration, expansion and deformation ... (2012) requirement of water for use in concrete mixtures. The sulphuric acid was procured from an open market and different ...

Durability of calcium aluminate and sulphate resistant Portland cement

This study aims to compare the performance of sulphate resisting (SR) Portland cement mortar (SRm) and calcium aluminate cement mortars (CACm) in both natural sewer environment and sulphuric acid.

The Mechanochemical Process and H2SO4 Treatment on the …

With the addition of 5 × 10 –3 mol −1 of sulphuric acid (H 2 SO 4), the diffraction peak of the anhydrite phase at [200] shifts slightly to lower 2θ values, whereas the intensity of the diffraction peak of gypsum at [020] and [02-1] was slightly higher compared to the sample without undergoing acid treatment.

(PDF) Acid Attack on Concrete-A Review

in sulphuric acid. Corrosion tests for concrete were. carried out using uniform test design and. nonparametric regression. Effects of water-cement. ratio and pH value on the sulphuric acid corrosion.

Utilization of neutralized spent sulfuric acid pickle liquor …

The research addresses the issue of utilization of neutralized spent sulfuric acid pickling liquor, deposited in 1.62 ha lagoons, derived from steel industry, in cement production.

Factsheet on: What is Gypsum?

Gypsum/Anhydrite for cement manufacture is supplied in crushed form for further fine grinding with cement clinker. C. Processing Natural Gypsum When Gypsum ... Additionally, all processes which end with the sub-product Sulphuric Acid are potential Gypsum producers. Neutralisation of acidic effluents with lime or limestone yields …

LS-Nikko

Sulphuric Acid: 1,360,000 MTPA Liquid SO 2 Plant: produced by deoxidizing refined SO 3 gas - 13,200 MTPA Liquid SO 3 Plant: produced by liquifying SO 3 from the acid plant - 33,000 MTPA High Purity Sulphuric Acid: 15,000 MTPA Gypsum Plant for cement from waste acid using CaCO 3 and Ca(OH) 2. Scrubbing Systems

Sulfuric Acid Attack on Ordinary Portland Cement …

The deleterious mechanism of acid attack is the dissolution of calcium hydroxide (a hydration product of cement paste) and the formation of gypsum (Ca 2 SO 4 .2H 2 O) and ettringite (Ca 6 Al 2...

Waste to resource conversion of crumb rubber for …

The reaction between sulphuric acid and calcium hydroxide which is present in concrete results into formation of gypsum [10]. It has been observed by many researchers that formation of gypsum plays minor role in deterioration of concrete [11], [12]. However, on further reaction between gypsum and calcium aluminate hydrate …

Method of producing sulfuric acid and hydraulic cement from gypsum

A method of making sulphuric acid which consists in preparing finely ground acid-washed argillaceous materials, mixing the same with finely ground gypsum in proportions to produce cement clinker, subjecting the mixture to heat in an oxidizing atmosphere until the particle size is materially reduced and a clinker is formed, …

Using concrete admixtures for sulphuric acid resistance

The improved resistance of the Caltite-modified concrete to sulphuric acid attack can be attributed to the substitution of calcium hydroxide, a vulnerable compound to acid attack, by calcium stearate, a product that is relatively more stable in acidic 30 Mass loss: % 25 20 15 10 In 7% acid In 3% acid 5 0 5 10 25 20 15 10 Control in 7% acid ...

PRODUCTION OF SULFUR FROM GYPSUM AS AN …

Gypsum (CaSO4. 2H2O) is produced by increasingly more industrial processes, for instance, when calcium carbonate or lime is used to neutralize sulfuric acid containing effluents or when apatite (Ca3(PO4)2. CaF2. CaCO3), the raw material used in phosphoric acid manufacture, is attacked by sulfuric acid.

Using concrete admixtures for sulphuric acid resistance

Using concrete admixtures for sulphuric acid resistance E. Hewayde PhD, PEng, M. L. Nehdi PhD, PEng, ... Both gypsum and ettringite possess little structural strength, yet they have larger volumes ...

The deterioration of mortar in sulphate environments

When cement mortar is exposed to sulphuric acid a dense layer of gypsum is formed; this is capable of retarding the deterioration process by acting as a surface …

Production, characterisation, and application of titanium gypsum…

1. Introduction. Titanium gypsum (TG) is a industrial gypsum produced during the manufacture of titanium dioxide (TiO 2) by the sulphuric acid process, after neutralisation of the acid waste solution with lime or calcium carbide slag (Zapata-Carbonell et al., 2019, Zhai et al., 2020).At present, every 1 ton of TiO 2 produced in China …

Piezoresistivity deterioration of smart graphene nanoplate/cement …

Sulphuric acid storage solutions with specific concentrations of 1%, 2% and 3% were prepared by diluting 98% sulphuric acid with deionized water. ... Long-term evolution of delayed ettringite and gypsum in Portland cement mortars under sulfate erosion. Construct. Build. Mater., 23 (2) (2009), pp. 812-816. View PDF View article …

Resource utilization of Industrial gypsum and its prospect

Pointing out that industrial routes such as preparing sulphuric acid co-production cement, calcium ferrite and conversion of ammonium to sulphuric acid by …

Production and use of by-product gypsum in the

The names of chemical gypsums are derived from the primary manufacturing products created during chemical processing [ 11. The chemical reactions resulting in the different gypsum by-products are given below: a) Phosphoric acid: Reaction between sulphuric acid and phosphorites. By-product: Phosphogypsum.

Sustainable Approach for Recovery of Sulfur from Phophogypsum

The obtained results show that the treatment of PG by sulfuric acid 20 and 50% at 60 C for 2 h is sufficient to make it suitable for used in the plaster and the cement respectively. View Show abstract

Response of Oyster Shell Ash Blended Cement Concrete in Sulphuric Acid

Response of Oyster Shell Ash Blended Cement Concrete in Sulphuric Acid Environment. May 2019; DOI:10.7176 ... aluminate hydrate to for m ettringite and gypsum had been reported by (Nabil ...

STRENGTH ASSESSMENT OF BLENDED CEMENT CONCRETE …

This paper presents the effect of sulphuric acid (H2SO 4) present in the mixing and curing water on the strength of blended cement concrete. The concrete is produced with mixing and curing water containing H2SO 4 with varying dosages of 100, 150, 300, 500 and 900 mg/l. In addition to this, control specimens were prepared with deionised water (without …

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