Effect of mining and utilizing bone coal on environment

The average air γ-ray dose rates measured from the field, road, bone coal, bone coal cinder and bone coal cinder bricks in the three bone coal mines in west Zhejiang Province, are 3.8× 102, 4.1× 102, 7.1 × 102, 4.0 × 102 and 7.1 × 102 nGy/h, respectively. The mean contents of 238U, 226Ra, 232Th and 40K in the bone coal of the three bone coal mines are 2.0× 103, 2.1 × 103, 3.9 × 101 and 6.1 × 102 Bq/kg, respectively, in the bone coal cinder(BCC) are 1.6× 103, 1.6× 103, 2.3× 101 and 4.5× 102 Bq/kg, respectively, and in the bone coal cinder brick(BCCB) are 1.2× 103, l.2× 103, 2.4× 101 and 4.0× 102 Bq/kg, respectively, and those in the reference soil are 3.4× 10’, l.0× 102, 4.9 × 101 and 4.9 × 102 Bq/kg, respectively. The annual mean of effective dose equivalent for public living in house buildings made with BCCB near the three mines is 6.8 mSv.

Approach to reducing the effect of bone-coal power station on radiation environment

The effect of two bone-coal power stations(6MWe) on environment was investigated within the scope of the dose contribution caused by various radionucildes in different ways.It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder(BCC),soot and ash in the catchers.

Natural radioactivity level of associated bone-coal mining area in Zhejiang Province

The geographic distribution, γ-radiation level and specific activity of radionuclides of the bone-coal mines in Zhejiang Province were reported. The weighted average of γ-radiation dose rate of the bone-coal mines is 566 nGy/h for 107 main bone-coal mines. The weighted mean activity of 238U, 226Ra, 232Th and 40K in the samples are 949, 918, 34 and 554 Bq/kg for 171 samples of bone-coal, respectively.

The collective dose equivalent in evaluated region of bone-coal power stations and bone-coal shafts

During 1991-1993, the radioactivity levels of the bone-coal mines were investigated in Hubei, Hunan, Ji-angxi, Zhejiang and Anhui Provinces, respectively, where the reserve of bone-coal is about 90% of our country’s total reserve. The annual additional collective dose equivalent within 80km evaluated region of bone-coal power stations in Nijiangkou and Anren is 1.7 and 1.9 man·mSv, respectively, and that of Zhuantanyan bone-coal shaft is 1.4 man·mSv. The collective dose equivalent caused by bone-coal cinder brick produced for 25 years in the five prov-inces is 1.6×105 man Sv.

Investigation of environmental activity levels of bone-coal min-ing area in five provinces

During 1991-1993,the activity levels of the bone-coal mines were investigated in Zhejiang,Hubei,Hunan,Jiangxi and Anhui Province,respectively,where the reserve of bone-coal is about 90% of our country’s total reserve.The average of γ radiation doserate level measured for bone-coal,bone-coal cinder(BCC) and bone-coal cinder brick(BCCB) in these provinces is about 500 nGy/h,400 nGy/h and 700 nGy/h respectively,while that for fields,roads and houses made of BCCB in corresponding regions of these provinces is about 200 nGy/h,260 nGy/h and 300 nGy/h respectively.It is shown that the environmental activity level of bone-coal mining area is about 3 times higher than the reference spots.

Investigation on natural radionucildes levels in multiple media in bone-coal mine areas of five provinces

This paper reports methods and results of the investigation of natural radionuclides levels in multiple me-dia in the bone-coal mine areas in Hubei, Hunan, Jiangxi, Zhejiang, and Anhui Provinces. In the studied bone-coal mine areas, the specific activities of 238U and 226Ra in the soil samples were 0.37 and 0.24 Bq/g, respectively; the spe-cific activities of 226Ra in the samples of bone-coal, bone-coal cinder and bone-coal cinder brick (BCCB) were 1.3, 1.4 and 0.9 Bq/g, respectively. In the water samples collected from the bone-coal mine areas, the average concentra-tions of natural uranium and 226Ra were 33μg/L and 58 mBq/L, respectively, while in the water samples collected from outside the bone-coal mine areas, they were 3.4μg/L and 45 mBq/L, respectively. In addition, the specific activi-ties of 238U and 226Ra in air aerosol samples from the bone-coal mine areas were 0.6 and 0.5 mBq/m3, respectively.

Survey of radon concentrations in bone-coal mining areas and inside BCCB houses in five provinces

It was investigated that the radon concentrations in bone-coal mining areas,in outside and inside BCCB houses and ordinary red-brick (ORB) houses of the reference points in Hubei,Hunan,Jiangxi,Zhejiang and Anhui Provinces. It was shown that the average annual radon concentration inside BCCB houses in the bone-coal mining areas in the five provinces ranges from 85.7 to 303 Bq/m3,with an average of 151 Bq/m3,which is 3 times that inside ORB houses at the reference points. The average annual radon concentration outside BCCB houses in the bone-coal mining areas in the five provinces ranges from 12.0 to 73.8 Bq/m3,with an average of 34.9 Bq/m3,which is 1.5 times that outside ordinary ORB at the reference points. And the radon concentration in shafts of Hubei and Zhejiang Prov- ince is 9.51×103 Bq/m3 and 965 Bq/m3,respectively. This report also shows the changing patterns of radon concen- trations with day,season,height,etc.

Estimation of the resident’s additional dose in bone-coal mining areas of the five provinces

This paper introduces the resident’s additional dose in bone-coal mining areas. The increase of the annual additional effective doses accepted by the residents living in the carbide-brick houses, the staffs working in the car-bide-brick houses and the miners working in the bone-coal mining areas of Hubei, Hunan, Jiangxi, Zhejiang and An-hui Provinces is caused by the rising of environmental radioactive level. The investigation of natural background ra-diation in the bone-coal mining areas indicated that both mining and utilizing bone-coal cause the rise of environ-mental radioactive level. The ranges of the annual additional effective dose accepted by the residents, staffs and min-ers is 1.9—6.8 mSv, 0.5—2.0 mSv and 8.2—71 mSv, and with an average of 3.8 mSv, 1 mSv and 40 mSv, respec-tively. The annual additional effective doses accepted by part residents and staffs exceed the dose limit of 1 mSv for public exposure, and part miners exceed the dose limit of 20 mSv for occupational exposure. And the contribution of dose caused by inhaled radon to the total additional effective dose is over 76%.

Radioactivity level of the ambient environment of Anren bone-coal power station

The radioactivity level of the ambient environment of Anren Bone-coal Power Station (BCPS) was investigated systematically. The γ radiation dose rate level in the environment, the content of 238U and 226Ra in the ambient soil and the farmland in the direction of downwind, the concentrations of 238U. 232Th. 226Ra 40K and 222Rn as well as α potential energy in air, and the concentrations of natural U and Th in effluent are all higher than the corresponding values of the reference site. The additional annual effective dose equivalent to the residents living in the houses made of bone-coal cinder brick is 2.7 mSv.

钝化剂对废弃石煤矿山铀污染土壤修复效果研究

本文采集江西省内某废弃石煤矿区周边实际铀(U)污染土壤为研究对象,选用泥炭和玉米秸秆炭作为有机钝化剂,以及将沸石和蛭石作为无机钝化剂对污染土壤进行钝化处理,以此考察不同钝化剂对污染土壤理化性质和U形态分布的影响。结果表明,四种钝化剂对污染土壤pH值影响不显著,沸石处理的土壤pH值虽有增加,但对U的钝化效果最不理想;泥炭对污染土壤中U的钝化效果最显著,与污染土壤混合培养5周后,铁锰氧化物结合态U占比降低了15.15%,硫化物及有机物结合态U占比增加了22.22%,与原始土壤中U形态分布对比,残余态U和硫化物及有机物结合态U总占比加和明显增加;蛭石对污染土壤中U也具有一定的钝化效果,与污染土壤混合培养3周后,U形态分布基本趋于稳定,铁锰氧化物结合态含量占比出现了较为明显的降低。

秦巴山地石煤产区燃煤型氟中毒流行现状调查分析

通过对秦巴山地7县(市)燃煤污染型氟中毒现状调查,结果表明,病区人口比15年前增加了近7.5倍,各县病区均有不同程度的扩大。8～12岁儿童氟斑牙患病率为48.71%,16岁以上成人氟骨症患病率为14.76%,氟骨症患病率比15年前的2.69%上升了448.70%。测定石煤、空气、玉米和辣椒氟含量严重超标。应尽快采取有效预防措施,防止发生更严重的后果。

D290树脂从石煤酸浸液中吸附钒的工艺

本文主要研究 D2 90树脂从石煤酸浸液中回收钒的工程过程 ,并在树脂选型、树脂上柱条件、洗脱液的组成等方面进行了详细实验。采用酸浸—离子交换新工艺后 ,可在减化流程、降低消耗的同时使回收率提高 15

钠化法提钒工艺条件的研究

研究了陕西某石煤矿提钒工艺。在原矿中加入少量添加剂氯化钠进行氧化焙烧,研究了最适宜的氯化钠用量、焙烧温度、焙烧时间等因素对氧化焙烧的影响。焙砂进行碱浸,研究了浸出时间、浸出温度、浸出碳酸钠用量、浸出液固比等因素对碱浸的影响。制定了合理的提钒工艺流程。结果表明,采用钙法低钠焙烧-碱浸工艺,在氧化钙用量为2%,食盐用量为8%,焙烧温度为850℃,焙烧时间为2 h,水浴温度70℃,水浴时间2 h,碳酸钠用量是8%,液固比3∶1的条件下,钒的浸出率达到了67.6%,试验结果比较理想。

含钒石煤无盐焙烧酸浸生产五氧化二钒工艺的研究

系统地研究了石煤无盐焙烧酸浸生产五氧化二钒的工艺技术 ,提出了各工序的工艺条件。焙烧转化率 57% ,锻烧回收率 98% ,总收率 47%～ 50 % ,具有较好的经济效益和有效地改进了环境污染。

陕南农村室内空气氟砷污染对儿童健康的影响

目的探讨燃用石煤区域室内空气氟、砷污染现状及对儿童健康的影响。方法于1996—2004年,在陕南5个县33个乡镇65个调查村共采集室内空气氟样本77件、砷样本186件。在燃煤区域3个市9个县区的每个县随机抽取3个乡,每个乡镇随机抽取3个村作为调查村。氟斑牙调查8～12岁儿童13120名,方法为TF法。砷中毒调查6～18岁儿童13386名,以地方性砷中毒诊断标准为评价依据。结果燃用石煤区域室内空气中氟含量范围在0.001～0.541mg/m3之间,均值为0.0384mg/m3;砷含量范围在0.00～63.83μg/m3之间,均值为4.76μg/m3。儿童氟斑牙患病率为45.50%,地方性砷中毒患病率为1.86%。室内空气氟、砷含量与氟斑牙砷中毒患病率之间无相关关系(r分别为0.061和0.128,均P>0.05)。结论燃用石煤区域室内空气氟、砷含量超过国家卫生标准(氟0.02mg/m3、砷3μg/m3),对当地儿童的健康已造成损害。

从酸浸石煤的萃取液中沉淀多聚钒酸铵

进行了酸浸石煤萃取液铵盐直接沉钒的工艺研究 ,对沉钒的主要影响因素 ,如加铵系数、溶液pH值、沉钒时间、温度等均进行了详细实验 ,得出了合理的沉钒工艺参数 :在pH =4.0 ,加铵系数 3 5 ;沉钒时间 6 0～ 90min ,以及温度不低于 80℃的条件下 ,从含钒 16～ 2 0g/L的萃取液中沉钒 ,沉钒率可达 98%以上 ,产品质量达国家标准。研究还表明 ,由于SO4 2 -,CO3 2 -,Na+,Cl-等的影响 ,从酸浸石煤萃取液沉钒与从水浸液沉钒相比 ,一些工艺参数如pH、KNH3

石煤中影响钒转浸率的主要因素研究

通过对石煤提钒焙烧阶段焙烧温度和添加剂作用、配比的研究，得出了焙烧阶段最适宜的焙烧温度、入炉温度和添加剂配比范围。实验结果表明，采用焙砂水浸后渣再用稀酸浸出的方法，钒的转浸率平均可提高１０％左右。

方山口石煤提钒焙烧相变机理的研究

对石煤提钒焙烧过程相变机理的研究是在石煤提钒工业生产中的主要研究课题之一。借助X衍射分析手段 ,详细研究了方山口石煤无添加剂焙烧和加添加剂氯化钠焙烧过程中 ,矿样中主要物相随温度升高的变化。

石煤钒矿氧化焙烧过程复合添加剂的研究

根据焙烧过程的特点 ,提出复合添加剂的思路 ,对焙烧过程的扩散、熔点和氧化剂等方面进行分析 ,研究出一种不含钠盐的复合添加剂 ,与现有的工艺进行比较 ,能明显地提高转化率 ,焙烧烟气不需处理可达到排放标准 ,而且生产成本可明显降低 。

含钒石煤提钒工艺研究

研究陕西某石煤矿提钒工艺。原矿通过加入少量添加剂氯化钠进行氧化焙烧,确定最适宜的氯化钠用量,焙烧温度,焙烧时间。焙砂进行水浸,可得到65%以上的钒浸出率。工艺简单,适应性强,沉钒容易。