Gas Emissivity of a Modified Cellulose Mix at the Temperature of 900°C

Abstract

This paper presents the findings of a study of gas emissivity and the volumetric gas flow rate from a patented modified cellulose mix used in production of disposable sand casting moulds. The modified cellulose mix with such additives as expanded perlite, expanded vermiculite and microspheres was used as the study material. The results for gas emissivity and the gas flow rate for the modified cellulose mix were compared with the gas emissivity of the commercial material used in gating systems in disposable sand casting moulds. The results have shown that the modified cellulose mix is characterized by a lower gas emissivity by as much as 50% and lower gas flow rate per unit mass during the process of thermal degradation at the temperature of 900°C, compared to the commercial mix. It was also noted that the amount of microspheres considerably affected the amount of gas produced.

Gas Evolution Quantitative Analysis at a Temperature of 900°C of a Cellulose Mixture Modified by Mineral Additives

“…An analysis of the temperature change shows that there is an exothermic effect for the commercially available cellulose profile and for the experimental ex6 profile, which maintains a constant temperature of the liquid metal for some time. The effect is associated with the presence of microspheres in both samples, which has also been observed in other studies [2,20,21]. …”

“…Owing to their thermal resistance [15][16][17][18][19]22], which is higher than that of the commercial mixture [2,9], materials for the pulp modification used in the study give the experimental mixtures a thermal resistance comparable to that of commercial products [20,21], while at the same time reducing gas evolution. This effect can be attributed to the temperatures characteristic of the additives used in the study.…”

“…Being materials of high thermal resistance, the additives modify the thermal resistance parameters of the cellulose-based mixture. Owing to the characteristics of this modified novel mixture, it can be considered a short-time, one-off thermal barrier for contact with liquid metal [10,14,20,21].…”

The gas evolution of a modified cellulose mixture used for gating systems in the no-bake mould process

“…Such summaries show which temperatures and sample mass losses correspond to the gas products which appear. The analysis of samples using the TG-DTG method detected no CH 4 ,-one of the decomposition products of cellulose included in all of the products [8,23,[26][27][28][29][30]-which should be explained by the difference in absolute mass in the test method. In addition, the samples for the TG-DTG analysis were subjected to grinding, which could facilitate the reduction of CH 4 to carbon dioxide or carbon monoxide in this scale and at relatively high gas flows.…”

Gas Evolution Qualitative Analyses From Modified Cellulose Mixtures During Thermal Degradation in Air and Argon

“…Pure or modified, cellulose is increasingly becoming the subject of numerous scientific studies. These studies endeavor to elucidate the mechanisms and processes which take place in cellulose-based materials when external conditions, such as temperature, change [12,13,14,17,21,22,23,25,26]. A high-temperature thermal treatment of cellulose-based materials naturally results in thermal degradation associated with mass loss which turns into gaseous by-products.…”