hexavalent chloride effect in cement grinding

Chromium in the cement can originate from: 1) raw materials or fuel, 2) magnesia-chrome kiln refractory brick, if used, 3) wear metal …

Tannery workers, welders, workers of pigments and paint industries are regularly exposed to hexavalent chromium that increases the risk of developing serious adverse health conditions. Occupational exposure to hexavalent chromium may induce a number of hematological disorders characterized by abnormal features of blood cells.

Chromium in the cement can originate from: 1) raw materials or fuel, 2) magnesia-chrome kiln refractory brick, if used, 3) wear metal from raw mill grinding process, if chromium alloys are used, and 4) additions such as gypsum, pozzolans, ground granulated blast furnace slag, mineral components, and cement kiln dust.

The Cement Additives Division delivers innovative technologies and advanced solutions for cement manufacturing. ... Grinding technology and vertical mills . 5 . Gypsum optimisation and setting time . Learn more. Visit Mapei Website. Mapei S.p.A. Via Cafiero, 22 20158 - Milan Italy - Phone 39-02-376731 - Fax 39-02-37673214 - Vat No ...

The advantages of using grinding aids in the cement industry on the performance of ball mills and air classifiers [1], as well as the effects of various dosages …

an important role in immobilizing chloride in portland cement system. CAC as an active aluminum-rich phase material was expected to enhance the chloride immobilization of portland cement. CAC had been widely used as an admixture in portland cement paste [38-43], and not only shortened the setting time but also improved the erosion resistance.

Cement from Denmark contains ferrous sulfate. The effect of representative admixtures on hexavalent chromium concentration in concrete was also evaluated, but technical …

Chromium is a naturally occurring element found in rocks, animals, plants, soil, and volcanic dust and gases. It comes in several different forms, including trivalent chromium and hexavalent chromium. Trivalent chromium is often referred to as chromium (III) and is proposed to be an essential nutrient for the body.

The exhaustive information about the chemical compositions and surface groups of CDs are uncovered by FTIR and XPS spectra (Fig. 2).Apparently, the wide absorption bands at 3100–3500 cm −1 are ascribed to O–H and N–H stretching vibrations [39].The peaks at 1716, 1620, and 1427 cm −1 arise from C O (Amide Ⅰ), C–N–H (Amide …

Hexavalent chromium [Cr (VI)] is one of the valence states (+6) of the element chromium. It is usually produced by an industrial process. Cr (VI) is known to cause cancer. In addition, it targets the respiratory system, kidneys, liver, skin and eyes. Chromium metal is added to alloy steel to increase hardenability and corrosion resistance.

Only a few studies have reported Cr levels in abnormal brain conditions. Two early studies have reported Cr levels in a total of 17 brain tumors, but neither found a difference between Cr levels in control cortex tissue and either astrocytoma (n = 15), oligodendroglioma (n = 1), or meningioma (n = 1) tissue (Guisun et al., 1991; Civit et al., …

Occupational exposure to hexavalent chromium can occur from inhalation of dusts, mists, or fumes containing hexavalent chromium, or from eye or skin contact. The following references provide information on exposure limits and analytical methods used to evaluate hexavalent chromium exposure. OSHA Cr (VI) standards for general industry ( 1910. ...

grinding and during cement storage. This requires the use of very high dosages of ferrous sulphate, causing costs to be higher than expected as well as triggering unfavourable side-effects (formation of red spots on the concrete surfaces, due to the characteristic colour of Fe3+ compounds, is very frequent).

PC exposure routes are inhalation, ingestion, and contact with skin or eyes with the potential to cause both surface and deep tissue damage. Generally, damage increases cumulatively with duration of exposure and concentration. Two well-documented hazardous components within PC are RCS and hexavalent chromium [Cr (VI)].

INTRODUCTION. The purpose of this review is to summarize information related to hexavalent chromium, Cr (VI), in the portland cement industry. The catalyst for initiating …

grinding and during cement storage. This requires the use of very high dosages of ferrous sulphate, causing costs to be higher than expected as well as triggering unfavourable side-effects (formation of red spots on the concrete surfaces, due to the characteristic colour …

water injection, and grinding aids, along with the high pH of the cement.[1] As a result, clinkers and cements contain soluble chromates, which are toxic and cause skin irritation and allergic ...

Physical adsorption is another way to immobilize the chloride ions in cement-based materials, being different from chemical binding. ... Effect of different grinding aids on property of granulated blast furnace slag powder. Mater. Struct., 48 (2015), pp. 3885-3893. CrossRef View in Scopus Google Scholar. Li et al., 2019.

The fixed-effects model was used (I 2 = 39.4%, P = 0.049, Figure 3) and the combined SIR was 1.06 (95% CI: 1.04–1.09). In subgroup analysis, the summary SIR was elevated for cement industry workers, and tanners, but not for welders or chromium workers. In addition, workers exposed to Cr(VI) had high cancer incidence in Europe.

In summary, hexavalent chromium is a regulated, toxic material that must be dealt with by implementing proper precautions, including: (a) Engineering controls where required (b) Respiratory protection if needed (c) Good housekeeping practices (d) Proper personal protective equipment (e) Good personal hygiene practices.

Cement from Denmark contains ferrous sulfate. The effect of representative admixtures on hexavalent chromium concentration in concrete was also evaluated, but technical limitations made evaluation difficult. Soluble chromium levels in cement ranged from 0.225 mg/kg in the US sample to 0.036 mg/kg in the Singapore sample.

Chromium in the cement can originate from: 1) raw materials or fuel, 2) magnesia-chrome kiln refractory brick, if used, 3) wear metal from raw mill grinding process, if chromium alloys are used ...

chromium and hexavalent chromium, for example the handling or application of powered or liquid chemicals which contain chromium and hexavalent chromium. Dermal The secondary route of exposure is through contact with the skin and eyes, particularly if hexavalent chromium is in a liquid form that can readily pass through or damage the …

4 Grinding Media If chromium alloys are used in grinding media and crushers, they may contribute metallic chromium. Klemm (1994) reports that in clinker ground with chrome alloy balls containing 17-28% chromium, the hexavalent chromium content of the cement may increase to over twice that in the original clinker.

The results indicate that the stabilization rate of hexavalent chromium in cement reaches 95% for specimens containing 0.5% potassium chromate by mass after 60 days. …

3. Uptake, Reduction, Genotoxic effects of Chromate. The Chemistry of chromium plays a major role in its cellular entry and toxic effects. Hexavalent chromium in the environment largely exists as the chromate oxyanion (CrO 4).Structurally, the chromate oxyanion is very similar to the sulfate oxyanion (SO 4) and thus utilizes general sulfate transporters on the …

Due to the toxicity and mobility of chromium, the disposal of chromium-containing waste is a pressing issue. Co-processing of chromium-containing waste in a cement kiln is currently one of the most effective methods. However, the presence of water-soluble hexavalent chromium (Cr(VI)) in cement limits the use of this method. In this …

CAS No. 1. Hexavalent chromium (Cr (VI)) compounds are a large group of chemicals with varying properties, uses, and workplace exposures. Hexavalent chromium is harmful to the eyes, skin, and …

The chloride ion in cement-based materials could also be immobilized by means of physical adsorption. And it was reported that most of these chloride ions were adsorbed by the electric double layer structure on the surface of C-S-H gel. ... Effect of different grinding aids on property of granulated blast furnace slag powder. Mater. …

page 09 4.2LONG-LASTING REDUCING EFFECT OF MA.P.E./C r 05 - ... with the implementation of cement additives and to optimise the grinding process in all its aspects. 03. ... significant economical impact on the cement industry. 3. HEXAVALENT CHROMIUM REDUCTION - CHEMICAL BACKGROUND While Cr (VI) is a strong oxidising agent in …

Chromium in the cement can originate from: 1) raw materials or fuel, 2) magnesia-chrome kiln refractory brick, if used, 3) wear metal from raw mill grinding process, if chromium alloys are used ...

In the case of the wet concrete, since it has a high pH of 12.5–12.9, it may alter the stratum corneum, facilitating the penetration of water-soluble compounds, causing irritation and ... Adverse hematological effects of hexavalent chromium : an overview. Interdisciplin. Toxical., 9 (2016), pp. 55-65, 10.1515/intox-2016-0007. View in Scopus ...