Figure 5. Tian Qian Heavy Industries cast this 160-metric-ton steel rudder arm with Bangni resin sand (shown after heat treatment).
图5 天乾重工生产的 160吨船用挂舵臂大型 铸钢件（热处理后）
• Due to the second hardening effect after pouring, molds have good rigidity.
• After pouring, the break-down properties are good and similar to those of furan resin sand.
• The reclamation and recyclability of used sand are good; the recycling rate can reach around 95%. Wuxi Foundry uses Chinese, dry attrition reclama- tion equipment, and the loss-on-ignition value of reclaimed sand can be controlled to below 1.5%. The molding sand, prepared with 95% reclaimed sand, 5% new sand, 1.2% resin and 0.3% hardening agent, has a final strength above 1.0 MPa.
• Since this resin does not contain formaldehyde and phenol, and when treated with the special purpose acid hardening agent, the gas, smoke and odor pro- duced from this resin sand during pouring are much less than that with other resin-bonded sands. Vari- ous organic substances have been tested by the China Building Material Test and Certification Centre; the conclusion is that free formaldehyde, benzene, meth- ylbenzene, dimethylbenzene (xylene) and free phenol could not be detected.
Application Results/Effects of Bangni Resin Operational conditions and environmental pro-
tection—Using Bangni resin sand, the gas, smoke and odor emitted after pouring are markedly reduced. The metalcasting facilities that use Bangni resin in produc- tion agree that compared to alkaline phenolic resin sand and furan resin sand, the gas, smoke and odor emitted from Bangni resin sand after pouring are all signifi- cantly decreased and working conditions are markedly improved. Figure 1 compares the situation after pouring Bangni resin and alkaline phenolic resin sand molds. Bangni resin sand has good breakdown properties
after pouring. For steel castings, the working conditions at shakeout, fettling and final finishing are significantly improved. The health hazard for operators caused by SiO2
dust during fettling also is reduced. Energy saving, emission reduction and sand rec-
lamation cost saving—The statistical data from Wuxi Foundry showed that when using ester-hardened silicate sand, the recycling rate of used sand was 77.5%, and 0.9 metric tons of new sand was consumed for every metric ton of steel castings produced. After changing to Bangni resin sand, the recycling rate of used sand reached 95.4%
表面滑润、柔韧，稳定性好，上涂料时，不出现浮 砂；
• （3）由于受热后有二次硬化作用，铸型的刚度较 好；
• （4）浇注后的落砂性能很好，与呋喃树脂自硬砂 基本相当；
• （5）旧砂再生、回用的性能好，旧砂的回用率可 达95%左右。无锡铸造厂用国产的干式摩擦再生 设备，再生砂的灼烧减量可控制在1.5%以下。 用95%再生砂、5%新砂，加树脂1.2%、硬化剂 0.3%配制的型砂，终抗拉强度在1.0 MPa以上；
• （6）由于树脂中不含甲醛和苯酚，在采用专用酸 性固化剂的条件下，浇注过程中产生的烟和气味 远低于其他各种树脂自硬砂。经国家建筑材料测 试中心对邦尼树脂中各种有机物含量进行检测， 结论是：游离甲醛、苯、甲苯、二甲苯和游离苯 酚等均未检出。
三．邦尼树脂的应用效果 1、在作业环境和环保方面
• （1）采用邦尼树脂粘结砂，铸型浇注后烟气明显 减少。已投产应用的铸造企业一致认为：与碱性 酚醛树脂、呋喃树脂相比，浇注后由树脂粘结砂 散发的刺激气味与烟气大幅度降低，显著地改善 了劳动环境。
（2）邦尼树脂砂浇注后的溃散性好，显著改善了 铸钢件落砂、清理和精整工作的作业条件，尤其是大 幅地降低了铸件清理时SiO2粉尘对环境的污染及对操 作者健康的危害。
2、在节能、减排和降低砂再生成本方面
无锡铸造厂的统计表明，采用酯硬化硅酸盐粘结砂 时，旧砂的回用率只是77.5%，平均每吨铸钢件耗用 新砂约0.9吨。改用邦尼树脂砂后，旧砂的回用率可达 95.4%，平均每吨铸钢件耗用新砂不到0.2吨，显著减少
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FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION May 2013
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