Cement is widely used as representative industrial material. In Korea, about 50 million tons of cement are consumed every year. In the manufacture of cement, raw materials containing NORM such as fly ash and bauxite are used. Therefore, the workers can be subjected to radiation exposure. The major exposure pathway in NORM industries is internal exposure due to inhalation of aerosol. Internal radiation dose due to aerosol inhalation varies depending on physicochemical properties of the aerosol. Therefore, the objective of this study was to investigate aerosol properties influencing inhalation dose in cement industries. In this study, aerosol properties were measured for two cement manufacturers. A particulate size distribution and concentration at various processing areas in cement manufacturing industries in Korea were analyzed using a cascade impactor. The mass density of raw materials and byproducts were measured using pycnometer. Shape of particulates was analyzed using SEM. The radioactivity concentration of Ra-226, Ra-228 for U/Th decay series was measured using HPGe. Particulate concentration by size was distributed log-normally with maximum at particle size about 7.2 μm in manufacturer A and 5.2 μm in manufacturer B. The mass density of fly ash and cement were 2.3±0.06, 3.2±0.02 g/cm3 respectively in manufacturer A. In manufacturer B, the mass density of bauxite and cement were 3.4±0.02, 2.9±0.01 g/cm3 respectively. The shape of particulates appeared as spherical shape in manufacturer A and B regardless of sampling area. Thus, a shape factor of unity could be assumed. The radioactivity concentrations of Ra-226, Ra-228 were 82±9, 82±8 Bq/kg for fly ash, and 25±4, 23±3 Bq/kg for cement in manufacturer A. In manufacturer B, the radioactivity concentrations of Ra-226, Ra-228 were 344±34, 391±32 Bq/kg for bauxite, and 122±13, 145±12 Bq/kg for cement. The radioactivity concentrations of Ra-226, Ra-228 in cement were less than raw materials such as fly ash and bauxite. It is because the dilution of the radioactivity concentration occurred during mixing with other raw materials in cement production process. This study results will be used as database for accurate dose assessment due to airborne particulate inhalation by workers in cement industries.

Cement production processes release various odor elements including acetaldehyde, hydrogen sulfide, formaldehyde and toluene etc. A three-dimensional numerical simulation using a commercial code of Computational Fluid Dynamics (CFD) was used to estimate the concentration profiles and dispersion distance around the local residential area. The calcination furnace, one of the main emission sources in the cement manufacturing process, discharged the odorous gases of H₂S, HCHO, CH₃CHO and C6H5CH₃at levels of up to 3.15 ppb, 5.1 ppm, 6.65 ppm and 0.74 ppm of H₂S, HCHO, CH₃CHO and C6H5CH₃respectively. This study found that as for the emission concentration of 1ppm for H₂S and CH₃CHO, the landing distance of the threshold value for each gas was extended in summer seasons at a low velocity. Low temperature of the flue gas at a high velocity also led to long dispersion.

One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The purpose of the present study was to investigate leaching properties of water-soluble hexavalent chromium by different manufacturing conditions of cement clinker. Raw materials were prepared to add different SiO2, Al2O3 and Fe2O3 sources. After the raw materials, such as limestone, sand and clay, iron ore was pulverized and mixed, and the raw meal was burnt at 1450˚C in a furnace with an oxidizing atmosphere. Leaching of soluble hexavalent chromium showed a tendency to decrease with an increasing LSF and IM. However, leaching of soluble hexavalent chromium increased with an increasing S.M. Alkali contents of iron source minerals is closely related to the leaching properties of soluble hexavalent chromium. Green sludge has the highest content of alkali added; leaching of water-soluble hexavalent chromium was mostly high. In order to reduce the water-soluble hexavalent chromium in cement, reducing the alkali content in raw materials is important.

Since it was developed by Joseph Aspdin, cement has been a common construction materials up to the present time.However, there are trace constituents in cement clinker. One of the trace constituents included in cement clinker, chromium,has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects thehuman body negatively. The aim of the present study was to investigate the concentration of water-soluble hexavalent chromiumin cement clinker by using industrial by-products. For that reason, raw materials were prepared to add different SiO2 , Al2O3,and Fe2O3 sources. After the raw materials such as the limestone, the sand and the clay, iron ore was pulverized and mixed,and the raw meal was burnt at about 1450oC in a furnace with an oxidizing atmosphere. The part in the raw materials of theclinker was substituted with slag, sludge, etc. and this was used to manufacturing cement clinker. To investigate the water-soluble hexavalent chromium content in clinker, raw meal was prepared by changing the modulus, the type, and the contentof clinker materials and tested concentrations of hexavalent chromium in the clinkers. To determine Cr+6 formation of theclinker, tests were done with raw meals adding chromium by using different industrial by-products. Consequently because thechromium was to be included in the raw materials of the clinker, production of Portland cement clinker was included with thechromium. Also, the chromium was converted into hexavalent chromium in the burning process.

High Energy Milling (HEM) is applied for the grinding of cement and this can lead to substantial refinement (<2μm) and mechanically activation of the powder particles. The present paper reviews the preliminary studies, explains the novel technique and suggests the route into commercial application. Particular attention is paid to wear results with an applied unit where no substantial wear was found after 4000 h of operation.

This paper was evaluated manufacturing properties for core material of self-healing capsules using cement powder, it was found that coagulants for coagulation of core materials were important factors in manufacturing core materials.

This paper was evaluated manufacturing properties for core material of self-healing capsules using cement powder, it was found that coagulants for coagulation of core materials were important factors in manufacturing core materials.