改良型湿法制备活性白土清洁生产及末端治理实验研究

传统湿法制备活性白土工艺中存在水耗、酸耗大等清洁水平较低的问题,本研究提出了在生产工艺流程中循环使用硫酸酸性废液、并从循环3次的硫酸废液中回收铝盐制备无铁硫酸铝的一种改良型湿法制备活性白土工艺,对末端治理采用电石渣替代石灰作为中和剂进行了探索性实验研究。实验结果表明,改良型湿法制备活性白土工艺对活性白土产品的理化性质无明显影响,产品质量符合行业标准,且酸的利用率从20%提高到约90%,水耗减少量为原工艺的1/3,无铁硫酸铝主要参数符合相关产品技术标准(HG/T2225-2001)。用电石渣作为中和剂处理酸性废液能够实现出水水质稳定达标,处理成本从255万元降低至210万元。本研究的实施使得活性白土的生产工艺清洁生产水平有较大提高。

Experimental research on cleaner production and end-treatment of activated clay craft using modified wet preparation

Traditional wet preparation of activated clay craft has some drawbacks, for example, consumption of large quantities of water and acid. In terms of cleaner production, performance of this technique is also poor. In the present study, a modified wet preparation of activated clay craft was proposed. After sulfuric acid waste was recycled three times, aluminum salt was extracted to produce iron-free aluminum sulfate. We also performed preliminary study on feasibility of using carbide slag as substitution of neutralizer lime in end-treatment. The results show that the modified method has no significant impacts on physical/chemical properties of activated clay. Utilization rate of acid increased from 20% to 90%, but water consumption decreased by 1/3. Main parameters of iron-free aluminum sulfate satisfied criteria of technical standard (HG/T2225-2001). Usage of carbide slag as neutralizer to treat acid wastewater promoted quality of effluent, by decreasing cost of water treatment from 2.55 million yuan to 2.1 million yuan. The modified technique significantly improved performance of cleaner production in activated clay preparation.