6019
ZVI aggregates were reusable ; however , an increase in the number of times ZVI was recycled decreased the decolourization rate .
 Chemical: ZVI; Chemical: ZVI
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: ZVI; Chemical: ZVI