Assessment of ferrous chloride and Portland cement for the ...
Type I/II Portland Cement (Lafarge, PA, USA) was used to stabilize the ferrous chloride treated COPR. 2.2. Treatment design. Ferrous salt in the form of ferrous chloride was used in this research to detoxify Cr(VI) and to mitigate the effects of …
The studies of the effect of sulfates added as ... - Springer
The calorimetric measurements were applied in testing the effect of some sulfates, used as Cr(VI) reducers in cement, as setting and hardening modifiers. The iron(II) sulfate is most commonly added as Cr reducer to cement on grinding. This was taken as a reference in the studies of the other potential chromium reducers, such as tin(II) and manganese(II) …
Criteria for a Recommended Standard Occupational Exposure ...
effects, including irritation, corrosion, ulcers, skin sensitization, and allergic contact dermatitis. An estimated 1,045,500 U.S. workers have dermal exposure to Cr(VI) in cement, primarily in the construction industry. NIOSH urges employers to disseminate this information to workers and customers. NIOSH also
Additives and methods for reducing hexavalent chromium in ...
The elimination of soluble hexavalent chromium is currently mainly obtained with the use of Iron(II) sulphate or Tin(II) sulphate or chloride (either in powder or in form of liquid additive) added during cement grinding or storage.
Hexavalent Chromium | NIOSH | CDC
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 respiratory system. NIOSH considers all Cr(VI) …
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(PDF) A review on the existence of chrome in cement and ...
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 …
PCA - The Portland Cement Association - America's Cement ...
Portland Cement Association. 5420 Old Orchard Road; Skokie, Illinois 60077-1083; 847.966.6200 ; 200 Massachusetts Ave NW, Suite 200; Washington D.C., 20001
Which Workplace Chemicals Raise the Risk for Lung Cancer ...
Hexavalent chromium compounds are used in a variety of industries, including water treatment, chemical synthesis, textile dyeing, and more. People who work with hexavalent chromium compounds are at an increased risk of developing lung cancer, along with cancer in the nasal cavity and sinuses. This is because the compounds can form mists, dusts ...
Technical papers Archive - Page 4 of 6 - C-ADD Mapei
Activators Antimony Blast furnace slag Blended cements Brown discoloration Calcium sulphate Cement additives Cement color Cement microscopy Chemical analysis Chromates Clinker mineralogy Clinkerization Concrete Controlled release Cost reduction Cr(VI) analysis Diffusion Dosing point Dry-mix mortars Early strengths Encapsulation Ettringite Fly ash Free lime …
Effect of FeSO4.7H2O and SnCl2.2H2O added as Chromium (VI ...
Reduction of Water Soluble Cr (VI) in Hydrated Cement Samples . The comparative analysis was carried out to know the effect of chromium hexavalent reducing additives such as ferrous sulphate (FeSO 4.7H 2 O) and stannous chloride SnCl 2.2H 2 O on the reduction of Cr (VI) by measurement of Cr(VI) before and after adding the reducing agent in ...
Effect of polyethylene glycol on chloride binding in ...
Effect of PEG on chemical binding capacity of chloride in mortar. As shown in Fig. 5 (a) and Fig. 7 (a), the AFt content of mortars containing PEG at the age of 28 d was significantly higher than that of the control group. AFm diffraction peaks cannot be adequately detected, especially when the content is low.
CONSTRUCTION ADDITIVES - PROQUICESA
High-performance, chloride-free superplasticizer additives, based on high-tech organic polymers, used to produce high-performance concretes. The superplasticizing action provides high workability and significantly reduces the water-cement ratio, thus providing pronounced increases in concrete compressive strengths and maintaining consistency for long-distance transport.
Cement Chromium VI Reducers | Holderchem
Although white cement does not have a high level of Chromium VI because of the raw material mix, many Portland types of cement do. Water-soluble hexavalent chromium can cause an allergic reaction to workers exposed to cement with high Chromium VI concentrations, often in the form of what is commonly known as cement dermatitis or eczema.
Chromium and you - HSE
Chromium (VI) compounds (the hexavalent forms of chromium – chromates, dichromates and chromic acid) pose the most significant health hazards. Their toxicity varies with how soluble (how easily they dissolve) in water. The least-soluble compounds, such …
Welding Health and Safety Respiratory Protection
Hexavalent Chromium (Cr +6) Most impacted industries and applications: – Electroplating – Welding – Grinding – Painting – Producers of chromates – Paint and coating production – Wood preserving – Chromium metal production – Steel mills – Iron foundries – Steel foundries – Construction using Portland Cement
EP2077979A2 - Additives and methods for reducing ...
EP2077979A2 EP07848831A EP07848831A EP2077979A2 EP 2077979 A2 EP2077979 A2 EP 2077979A2 EP 07848831 A EP07848831 A EP 07848831A EP 07848831 A EP07848831 A EP 07848831A EP 2077979 A2 EP2077979 A2 EP 2077979A2 Authority EP European Patent Office Prior art keywords antimony iii cement compound added Prior art date 2006-11-02 Legal …
Influence of quartz powder and silica ... - Scientific Reports
QP was obtained in laboratory by grinding normalized quartz sand in a planetary mill. ... to the dilution effect of the cement. ... resistance within 52–104 Ω m have a …
Additives and methods for reducing hexavalent chromium in ...
Hexavalent chromium, Cr(VI), is one of the oxidation states of the element chromium and is the toxic form that poses a health risk to workers exposed to it. Chromium is the 21st most abundant element, the sixth most abundant of the transi-
EFFECT OF RAW MATERIALS AND REDUCTION AGENTS ON HEXAVALENT …
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 CHROMIUM COMPOUNDS - Chromium, Nickel …
Hexavalent chromium was found in 18 of 42 US cement samples at concentrations ranging from 0.1 to 5.4 μg/g, with a total chromium content of 5–124 μg/g (Perone et al., 1974). Portland cement contains 41.2 ppm (mg/kg) chromium (range, 27.5–60), due to …
Spectrophotometric Determination of Water-Soluble ...
lent chromium, due to its toxic effects. The hexavalent chromium is considered an undesirable component of cement because of its potential health consequences. Cr (VI) content of Portland cement contributes to the debili- tating medical condition known as dermatitis [2-7]. Due to increasing health-related concerns, the amount of Cr
Chloride binding into hydrated blended cements: The ...
The effect of limestone seemed to be related to decreased ability of chloride binding into carboaluminate phases that formed during the hydration of calcium carbonate-containing cement. Alkalinity of the synthetic pore solution generally influenced the course of binding with the effect being more pronounced at lower chloride concentrations.
ES2395423T5 - Additives and procedures to reduce ...
The elimination of soluble hexavalent chromium is obtained mainly and currently with the use of iron (II) sulfate or stannous (II) sulfate or chloride (either in powder or in the form of liquid...
Technical Notebook HEXAVALENT CHROMIUM ... - C-ADD …
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).
Additives and methods for reducing hexavalent chromium in ...
Hexavalent chromium exposure occurs through . breathing it in, ingesting it in food or water, or direct contact with the skin. What are the known health effects of inhaling hexavalent chromium? Hexavalent chromium compounds have been shown . to cause lung cancer in humans when inhaled. The Report on Carcinogens. lists hexavalent chromium
US20060169177A1 - Liquid additive for intergrinding cement ...
Exemplary compositions and methods for reducing hexavalent chromium in cementitious compositions involve the use of a liquid additive composition, comprising stannous chloride. Along with the stannous chloride may be used at least one co-additive comprising an antioxidant, oxygen scavenger, or mixture thereof, and/or at least one agent comprising a cement …
Long-term hexavalent chromium exposure facilitates ...
Colorectal cancer (CRC) is among the leading causes of cancer-related mortality worldwide. Hexavalent chromium [Cr(VI)] is often present in groundwater. Chronic Cr(VI) exposure is suggested to be one of the main factors inducing cancer. However, the correlation between Cr(VI) and CRC remains unclear …
Amine-containing agents of hexavalent chrome reduction in ...
Method of recovery of hexavalent chromium in cement compositions, including: mixing with cement clinker during the grinding of clinker in cement reductant selected from the group consisting of: (A) A hydroxylamine represented by formula, where each of R 1 and R 2 represents hydrogen or C 1-C 18 alkyl, alanovoy or aryl group, or a salt or ...
Hexavalent Chromium - Occupational Safety and Health ...
• impurity present in portland cement. How hexavalent chromium can harm employees Workplace exposure to hexavalent chromium may cause the following health effects: • lung cancer in workers who breathe airborne hexavalent chromium • irritation or damage to the nose, throat, and lung (respiratory tract) if hexavalent chromium