Qee zaum, thaum cov roj hmab cov pa roj hmab yog siv los ua pob tshab los yog semi- pob tshab khoom, lawv tuaj yeem tig daj. Tshwj xeeb tshaj yog tom qab kev ua daj ua paug, kev daj ua daj ua kom pom tseeb.
Ib qho ntawm cov laj thawj rau kev daj daj yog li Silica yuav muaj cov impurities thiab tig daj vim oxidation thaum kub. Qhov thib ob yog tias cov khoom lag luam uas muaj nyob hauv cov roj hmab nyoos yog oxidized rau hauv cov noob kob xim. Thib peb, kev txiav txim siab ntawm cov portosides kuj tseem tuaj yeem tsim cov tshuaj daj.
Yuav kom kov yeej txoj kev yaig, nws yog ib qho tsim nyog los saib xyuas cov roj silica, thiab lwm lub sijhawm, xyuam xim rau kev txhim kho cov roj hmab raw. Qhov qis - molecular - qhov hnyav cov khoom siv yuav tsum tsis txhob siv rov qab dua. Thaum kawg, anti - yehying vulcanizing cov neeg sawv cev kuj tseem siv tau los ua kom tiav qhov ov- cov nyhuv daj