柱状竹炭基肥挤压造粒成型工艺的研究

Research on extrusion granulation forming process of columnar bamboo charcoal based fertilizer

为探索挤压造粒工艺对竹炭和木醋液加以利用,用来制备成型质量优良的柱状竹炭基肥,将自制的挤压成型模具与万能试验机相结合搭建成挤压造粒平台。以抗渗水性、密度和抗压强度作为成型质量的综合评价指标,通过单因素试验来考察粘结剂种类、粘结剂添加量、竹炭含量、成型压力和模孔孔径5个因素对试验指标的影响情况;在此基础上,又进行了正交试验,筛选最佳成型工艺。试验结果表明,粘结剂种类、粘结剂添加量、成型压力和模孔孔径对抗压强度有显著影响,竹炭含量对抗压强度影响不显著;粘结剂种类、粘结剂添加量和模孔孔径对抗渗水性影响显著,竹炭含量、成型压力对抗渗水性影响不显著;粘结剂种类、竹炭含量对密度影响显著,其他因素对密度影响不显著。运用综合平衡法得到的最佳组合方式为:竹炭含量50%、粘结剂为木质素磺酸钠、粘结剂添加量为20%、成型压力为10 MPa、模孔孔径为5 mm。此条件下,成型质量最佳,抗压强度为36.90 N,密度为1.190 g·cm-3,抗渗水性为93.45 min。

In order to explore the use of extrusion granulation technology to prepare high quality columnar bamboo charcoal based fertilizer using bamboo charcoal and wood vinegar,, the homemade extrusion molding device and universal testing machine were combined as an extrusion granulation platform. Single factor experi- ment was carried out, employing compressive strength, water resistance, and density as comprehensive judging indexes, to examine the effect of binder type, binder content, bamboo charcoal content, forming pressure, and die aperture on test index. On this basis, an orthogonal experiment was carried out to screen the best molding process. The results showed that binder type, binder content, molding pressure and die aperture had significant effects on the compressive strength, while compressive strength influenced by bamboo charcoal content was not significant. The water resistance was remarkably influenced by binder type, binder content and die aperture, while it was not significant affected by bamboo charcoal content and forming pressure. The binder type and bamboo charcoal con- tent showed significant impacts on the density, while other factors had no significant effect on the density. The best combination by means of comprehensive balance method was 50% of bamboo charcoal content, sodium lig- nin sulfonate being binder type, 20% of binder content, 10 MPa of molding pressure, and 5 mm of die aperture. Under the conditions, the compressive strength, density and water resistance were 36.90 N, 1.190 g cm3, and 93.45 min, respectively.