| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥3,000,000 (Direct Cost: ¥3,000,000)
|
|---|
| Research Abstract |
Based on the results of experiments conducted in the first year, although an improvement in compression strength was desired in ettringite production systems, it was clear that alkali elution was significant. Low-alkalinity is required when a material is to be used for agriculture or horticulture, and so this year, investigations into various chemical additives were conducted to produce a low-alkali solid. In short, industrial by-product soil was used as a primary raw material, with attempts made to add gypsum, quick lime and various chemicals (sulfate, carbonate). Subsequently, dry mixing and pulverization were performed using a planetary ball mill, followed by molding/hydrolytic curing. In addition, the effects of lead on pulverization treatments were investigated this year by solidification experiments. The results lead to the following conclusions.
(1) Compression strength is greatly improved when producing ettringite, but alkali elution increases. In other words, it is necessary to maintain alkalinity in order to produce ettringite.
(2) Free CaO must undergo a reaction to reduce alkalinity, and the addition of sulfate (aluminum sulfate, ammonium sulfate, magnesium sulfate, ferrous sulfate) or carbonate (magnesium carbonate) was investigated. Low alkalinity was achieved when aluminum sulfate and ammonium sulfate were added, and some measure of strength was obtained when aluminum sulfate was used.
(3) Regarding elution of heavy metal lead (in this instance, lead chloride reagent added in minute amounts), lead elution was inhibited by pulverization treatment, regardless of the state of the raw material pulverization product, and even when in solid form.
From the above, it is clear that production of a solid with low alkali elution and reduced lead elution are achieved by the use of aluminum sulfate as a chemical additive, and the use of pulverization treatment using a planetary ball mill.
|
