Effects of Cement Production on the Environment and Human Health at Sekandji, Benin

Cement is made by grinding several raw materials. The cement industry contributes to the development of any society. Benin has four cement companies, including Sèkandji. Exposure to cement dust can cause a number of ailments. Cement production also contributes to the emission of greenhouse gases (GHGs), which contribute to global warming. The study aims to assess the effects of cement dust on the environment and on the health of the population of Sekandji. This was a cross-sectional study with descriptive and quantitative aims, conducted from May 21 to June 23, 2024. Data were collected using an interview guide from people living in the vicinity of the cement plant, who gave their informed consent to participate in the study. An observation grid was used to assess the environment. Particulate matter was sampled in the immediate vicinity of the cement plant using an AM-4812 anemometer and an air quality monitor. Sampling was non-probabilistic and purposive. Targets were selected for reliability and accuracy of data collection. Data collection was carried out using Kobo Collect software for data collected with the interview guide. Excel 2013 was used for data analysis, tables and graphs, and Microsoft Word 2013 for data entry. A total of 105 residents were selected in the vicinity of the cement plant. The average age of respondents was 35, with a minimum of 20 and a maximum of 50. The dominant age group was between 30 and 39. Males (70) dominated, with a sex ratio equal to 2. The vast majority of respondents (92.38%) said they had noticed or heard about an increase in health problems since the cement plant was set up. However, 70.48% of respondents claimed to have no information on the effects of cement production on the environment. Few respondents (29.52%) were aware of the effects of cement production on the environment. Respiratory, dermatological and ocular disorders were cited as being linked to cement. PM2.5 and PM10 particles were present in very high proportions in the air. The implementation of a serious industrialization policy that takes urbanization into account will guarantee the health safety of the population.

Guangxi Beihai China Resources Cement Shoots at Putting into Production in May 2014

China Resources Cement in Hepu County of Beihai City is building two new type dry method cement production lines with two sets of 9 MW pure low temperatures residual heat power generating systems matched. Phase I of the project will be invested CNY I billion, and had been invested CNY 0.13 billion in 2012. China Resources Cement is shooting at putting the lines into production in May 2014.

Preparation and Performance Research of Cement-based Grouting Materials with High Early Strength and Expansion

Main performance of the cement grouting materials made up by Portland cement（PC） and sulphoaluminate cement（SAC） was investigated in this program, a kind of expanding agent（EA） which was mainly constituted by metakaolin and alunite was utilized for the compensation of the shrinkage, the hydration products and micro structure of the grouting materials were researched by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results showed that a high expansion rate of the grouting materials could be reached as the expanding agent mixed in 6% of PC mass; the addition of SAC in the S2（PC：SAC：EA=34：6：2.25） brought a further improvement of the expansion rate of the grouting materials, the analysis of XRD and SEM showed that due to the reaction of expanding agent and SAC in the grouting materials, more ettringite crystal was generated, which resulted in a higher early strength, the addition of SAC played an expansion and strength reinforcement role in the grouting materials.

Influence of Cellulose Ethers on Hydration Products of Portland Cement

Cellulose ethers are widely used to mortar formulations,and it is significant to understand the interaction between cellulose ethers and cement pastes.FT-IR spectra,thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article.The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste,but the major hydration products,such as CH（calcium hydroxide）,ettringite and C-S-H,appeared later in the modified cement pastes than in the unmodified cement paste.The cellulose ethers decrease the outer products and increase inner products of C-S-H gels.Compared to unmodified cement pastes,no new products are found in the modified cement pastes in the present experiment.The HEMC and HPMC investigation shows almost the same influence on the hydration products of Portland cement.

Comparison of Temperature Field Distribution between Cement Preclinkering Technology and Cement Precalcining Technology

Through the comparison of calcination conditions between cement preclinkering technology and cement precalcining technology,we studied the characteristics of temperature field distribution of cement preclinkering technology systems including cyclone preheater,preclinkering furnace,and rotary kiln.We used numericalsimulation method to obtain data of temperature field distribution.Some results are found by system study.The ratio of tailcoalof cement preclinkering technology is about 70%,and raw mealtemperature can reach 1070 ℃.Shorter L/D kiln type of preclinkering technology can obtain more stable calcining zone temperature.The highest solid temperature of cement preclinkering technology is higher than 80 ℃,and high temperature region（〉1450 ℃）length is 2 times,which is beneficialfor calcining clinker and higher clinker quality.So cement preclinkering technology can obtain more performance temperature filed,which improves both the solid-phase reaction and liquid-phase reaction.

Influence of Characteristics of Alumina-silicate Raw Materials on the Formation Process of Clinker

The traditional alumina-silicate raw materials, for example, clays, in the precalcining technique of cement production, have been replaced by low grade and high silica content sandstones, shales, and industrial waste residues, including fly ashes, slag, and others. The results are the change of compositions and characteristics of raw materials applied and a great effect on cement calcination process and clinker formation. In this work, the cement clinker formation process of different alumina-silicate raw materials to replace clay raw material was studied by chemical analysis, X-ray diffraction, differential thermal analysis, and high temperature microscope based on the characteristics of the alumina-silicate raw materials. The formation heat of the clinker was determined by the acid dissolution method. Influence of different alumina-silicate raw materials on the clinker burnability and formation process was studied. The results show that the changing of alumina- silicate raw materials, especially using industrial waste residues, can reduce the formation temperature of high temperature liquid phases, improve the burnability of raw materials, reduce the formation temperature and formation heat of clinker. And this study also observed the formation temperature and transformation of high temperature liquid phases in the heating process of raw materials by high temperature microscope.