Kev ntsuas kev txhim kho:
1, tswj qhov zoo ntawm cov ntaub ntawv raw;
2, siv nruj me ntsis raws li qhov tsim nyog feem ntawm cov khoom siv thib ob;
3, hlau melting thiab refining siab - cov neeg ua haujlwm zoo;
4, siv cov lim dej ceramic;
5, kev thauj mus los ntawm lub tshuab nqus tsev;
6, ceramic spoons, crucibles, tiv thaiv tube, pov tseg ferrous khoom cuab yeej;
7, tsis tu ncua tu cov pwm, cov cuab yeej, lub ntsej muag;
8, zoo pwm tso tawm tus neeg saib xyuas cov ntaub ntawv txhawb nqa;
9, ua kom ib puag ncig huv si.
