电镀工艺学 电镀三废治理.ppt

* 19.7 含重金属废水处理 化学沉淀法 ； * 化学沉淀法 表 12—2 部分金属离子溶度积与析出PH值 金属离子 金属氢氧化物 溶度积常数 析出PH值 排放浓度 mg/L Mn2+ Cd2+ Ni2+ Co2+ Zn2+ Cu2+ Cr3+ Fe3+ Mn(OH)2 Cd(OH)2 Ni(OH)2 Co(OH)2 Zn(OH)2 Cu(OH)2 Cr(OH)3 Fe (OH)3 4.0×10—14 2.5×10—15 2.0×10—16 2.0×10—16 7.0×10—18 5.6×10—20 6.3×10—31 3.2×10—38 9.2 10.2 9.0 8.5 7.9 6.8 5.7 3.0 10.0 0.1 0.1 1.0 5.0 1.0 0.5 美国在1980年评选重金属废水处理方法中，首先推荐的就是石灰中和法。 * （1） 含镍废水处理 反渗透处理镀镍废水 ； 离子交换法 。 * * （2）含铜废水处理 离子交换法 ； 化学沉淀—隔膜电解法； 混合电镀废水综合处理技术 。 * * （3）镀液中有机物的去除 * * * 19.8 酸碱废水处理 自然中和法 ； 药剂中和法 过滤中和法 ； 扩散渗析法回收硫酸 * 19.10含尘及有害气体的处理方法 含尘气体的处理 ； 洗涤除尘 过滤除尘 * （1）氮氧化物气体的净化处理 * （2）铬酸雾的处理 铬雾净化器 ； 铬雾抑制的方法 * （3）酸碱雾的抑制 * 19.11电镀污泥的处置及回收利用 电镀污泥的安全处置 ； 电镀污泥的综合利用； * “The primary health effect of concern is lung cancer caused by airborne exposures to hexavalent chromium. Chronic inhalation increases the risk of lung cancer. All Cr(VI) compounds are considered to be carcinogenic. Zinc chromate is the strongest carcinogen of the chromates used in industry. “Symptoms from breathing Cr(VI) may include runny nose, sneezing, coughing, itching, and a burning sensation from irritation or damage to the nose, throat, and lung. Sores can develop in the nose and result in nosebleeds. Ulcers can develop and with continuous exposure, also permanent perforations (holes) in the nasal septum (the wall separating the nasal passages), as seen in the top photo of a young woman who was employed in chrome plating small appliance parts. “In some cases employees become “allergic” and sensitized to hexavalent chromium so that inhaling chromate compounds can cause work-related asthma, such as wheezing and shortness of breath.” “Hexavalent chromium in contact with skin acts as both sensitizer and irritant. Once developed, chrome sensitivity becomes fairly persistent; in such cases, even contact with chromate-dyed textiles or wearing of chromate-tanned leather shoes can cause or exacerbate contact dermatitis. “Dermal exposures to hexavalent chromium can result in skin ulcers common