| 摘要 |
PURPOSE:To coagulate and settle sludge formed in a chemical conversion process for phosphate coating in a very short period of time and decompose the sludge easily by adding a high-molecular floceulant to the treating solution. CONSTITUTION:In a process of forming phosphate film on steel, zinc, or zinc alloy materials, a high molecular flocculant is added either to the treating solution or to base liquid of the treating solution in advance. Thus the size of sludge particles formed at the chemical conversion process is enlarged, its settling property is improved, and its separation is facilitated. As the above high molecular flocculant, many agents are known, among which those basing on polyacrylamide are especially preferable. The amount of addition is selected from the range 0.001-0.3g/l basing on the treating solution. This method increases the speed of sludge settlement, improves continuous separation efficiency, allows the use of compact equipment, and therefore contributes to cost reduction. |
