可溶性矿床的综合开采及利用

锡林郭勒苏尼特碱业有限公司的天然碱矿床是可溶性矿床 ,过去采用单一的采掘机械开采 ,回采率仅为78%左右。为此 ,公司组织技术人员总结经验、分析造成损失的原因 ,在扩采的基础上采用了多种采掘机械联合开采和配套碱田工艺系统进行碱份回收的综合工艺 ,大幅度减少了损失和贫化 ,回采率提高到 95 %以上 ,使有限的碱资源得以充分利用。     

Breakthrough analysis for CO2 removal by activated hydrotalcite and soda ash

Carbon dioxide sorption rate parameters and sorption capacities on two different regenerable sorbents, namely hydrotalcite and activated trona, were investigated in a fixed bed flow adsorber, in the temperature range of 400–527 °C and 80–152 °C, respectively. Hydrotalcite, which was activated at 550 °C, was shown to give total and breakthrough CO₂ sorption capacities as high as 1.16 and 0.70 mmol/g, respectively, at 452 °C, in the absence of water vapor. In the presence of excess water vapor, the total CO₂ sorption capacity was not affected much, however a decrease in the breakthrough capacity and on the sorption rate constant was observed, especially at lower temperatures. In the presence of water vapor, activated trona was shown to give comparable total and breakthrough CO₂ sorption capacities, at much lower temperatures (T < 100 °C). The deactivation model gave good predictions of the CO₂ breakthrough curves and it was successfully used for the evaluation of the adsorption and the deactivation rate constants.     

Hydrothermal gasification of Rosa Damascena residues: Gaseous and aqueous yields

The gasification of Rosa Damascena residues – by-products of the rose-oil industry – was investigated under hydrothermal conditions at 500 °C and 600 °C, 35–45 MPa pressure with a reaction time of 1 h. The experiments were performed in the absence and presence of catalysts of K₂CO₃ and trona in a batch type reactor. The composition of the gaseous and aqueous products was determined by gas chromatography and high performance liquid chromatography, respectively. H₂, CO₂ and CH₄ are the main gaseous products while carboxylic acids (formic acid, acetic acid, glycolic acid) are the main components found in the aqueous phase followed by furfurals, phenols, aldehyde and ketones. More gaseous products were obtained at the higher temperature of 600 °C. Adding catalyst was found to aid the conversion process but the effect was only slight. Rosa Damascena residues have the potential to be a useful source for H₂ production in the future.     

吴城天然碱矿溶采理论与实践

河南桐柏吴城天然碱矿床主要矿物为倍半碱和岩盐,矿层薄、埋藏较深,由于碳酸钠与碳酸氢钠具不相称溶解性,溶采中互相制约。研究采用NaOH助溶、双井分层压裂连通多层同时可控溶采工艺,基本解决了面临的难题。所获参数已作为大厂建设的设计依据,可以提高溶矿能力,提高资源回收率,简化地面生产工艺。     

Contribution of trona (magadi) into excessive fluorosis--a case study in Maji ya Chai ward, northern Tanzania

Excessive fluoride ingestion predominantly comes from drinking water sources. However, prevalence and severity of dental and skeletal fluorosis in northern Tanzania have been reported to be higher than would be expected from ingestion of fluoride through drinking water alone. This study aimed at investigating the contribution of "trona" (also locally known as magadi) a food additive, to the prevalence and severity of fluorosis in northern Tanzania. The study was carried out in four villages (Embaseni, Kitefu and Ngurdoto) in Maji ya Chai ward; and Nkoanekoli in Poli ward, in Arusha region, Tanzania. Analysis of fluoride concentrations was carried out in drinking water sources as well as in magadi samples. Assessment of the prevalence of dental fluorosis using Dean's Index Method was carried out for a population of 2217 pupils in four primary schools located in the case study area. Fluoride concentration in drinking water sources was found to range from 1.7 to 11.3 mg/l, while the concentration in magadi samples in case study villages were in the range of 0.21 to 0.9 mg/g. Total fluoride ingestion through magadi and water were established to be 11.74 mg/person/day in Embaseni, 36.1 mg/person/day in Ngurdoto, 10.88 mg/person/day in Kitefu and 5.7 mg/person/day in Nkoanekoli villages. Levels of total fluoride ingestion were directly correlated with Community Fluorosis Index (CFI) values, which were found to be 3.32 (in Embaseni), 3.67 (in Ngurdoto), 2.2 (in Kitefu) and 1.47 (in Nkoanekoli). The village with the highest fluoride consumption rate showed the highest CFI as well. High levels of fluoride concentrations in magadi suggest that excessive fluorosis in northern Tanzania may be due to the use of magadi in food preparations.