Macadam J, Parsons S A
School of Water Sciences, Cranfield University, Cranfield, MK43 0AL, UK.
Water Sci Technol. 2004;49(2):153-9.
This paper focuses on developing a reproducible method for reducing calcium carbonate scale formation on heated surfaces where scaling can cause serious problems. It is known that calcium carbonate precipitation is sensitive to impurity ions, such as iron and zinc, even at trace concentration levels. In this paper two sets of experiments are reported. The first experiments were undertaken to investigate the effect of zinc, copper and iron dosing on CaCO3 nucleation and precipitation. Results from the experiments showed that the most effective inhibitor of CaCO3 precipitation was zinc and the effect was linked to dose levels and temperature. Copper and iron had little effect on precipitation in the dose range investigated. The second trial was undertaken to translate the precipitation data to scale formation. These tests were undertaken at 70 degrees C. 5 mg x L(-1) zinc dose reduced the scale formation by 35%. The effect of iron on calcium carbonate scaling rate was not significant. The physical nature of the material on which the scale is formed also influences the scaling. The scaling experiment was also used to investigate the effect of different surface material (stainless steel, copper and aluminium) on CaCO3 scale formation. Copper surface scaled the most.
本文着重于开发一种可重复的方法，以减少加热表面上碳酸钙垢的形成，在这些表面上结垢会引发严重问题。众所周知，即使在痕量浓度水平下，碳酸钙沉淀也对诸如铁和锌等杂质离子敏感。本文报道了两组实验。第一组实验旨在研究锌、铜和铁的投加对碳酸钙成核和沉淀的影响。实验结果表明，碳酸钙沉淀的最有效抑制剂是锌，且该效果与投加剂量水平和温度有关。在研究的剂量范围内，铜和铁对沉淀几乎没有影响。第二组试验旨在将沉淀数据转化为垢的形成情况。这些测试在70摄氏度下进行。5毫克/升的锌投加量使垢的形成减少了35%。铁对碳酸钙结垢速率的影响不显著。形成垢的材料的物理性质也会影响结垢情况。结垢实验还用于研究不同表面材料（不锈钢、铜和铝）对碳酸钙垢形成的影响。铜表面结垢最多。
