Wyniki wyszukiwania - BazTech

Ograniczanie wyników

3 Physicochemical Problems of Mineral Processing

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Kinetics of simultaneous recovering of Au and Ag from CTs by chloridizing volatilization methods

Wang Weiwei, Li Zhengyao, Yang Shanshan, Ma Kai, Gao Xin, Han Shaoqi, Hou Shaochun, Miao Hecheng

Physicochemical Problems of Mineral Processing

2023

Vol. 59, iss. 6

art. no. 172522

Cyanide Tailings (CTs) are known as hazardous resources that accumulate hundreds of millions of tons, threatening the ecological environment. This work proposes an eco-friendly and efficient way to recover gold and silver from CTs. The effects of calcium chloride dosage, silicon dioxide dosage, pellet moisture content, roasting temperature, and roasting time on Au and Ag chloridizing volatilization were studied. The kinetics of simultaneously recovering of gold and silver from cyanide Tailings by chlorination roasting was investigated. It was determined that the chloridizing volatilization rates increased with increasing calcium chloride dosage, temperature and decreasing silicon dioxide dosage, pellet moisture content. The chloridizing volatilization kinetics followed a shrinking core model, with inter-diffusion through gangue layer as the rate determining step. This finding is in accordance with the apparent activation energy (Ea) of 24.01 kJ•mol-1 (Au) and 24.62 kJ•mol-1 (Ag). The orders of reaction with respect to moisture content, temperature, calcium chloride dosage and silicon dioxide dosage were also achieved. The rate of reaction based on diffusion-controlled process can be expressed by semi-empirical equations. The control steps of the gold and silver recovery process were investigated by the kinetic study, which provided theoretical guidance for the optimization of the method.

Effect and mechanism of depressant CK102 on flotation separation of fluorite and dolomite

Li Zhengyao, Wang Xuewen, Xu Chengyan, Sun Tichang, Liu Weiran, Wei Jinzhi

Physicochemical Problems of Mineral Processing

2022

Vol. 58, iss. 3

art. no. 145796

For a low grade dolomite type fluorite ore in the Hebei province, it was observed that the depressant CK102, a mixture of sulfuric acid, sodium silicate and aluminum sulfate, can effectively inhibit the gangue mineral dolomite in the flotation of fluorite. However, the inhibition mechanism of the depressant is still unclear. In this paper, the flotation separation performance and underlying mechanism of CK102 inhibiting dolomite were investigated through mineral flotation tests, adsorption measurements, infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). The flotation results showed that the inhibition effect of CK102 on dolomite flotation was much more remarkable than that of fluorite flotation under optimum conditions. Adsorption measurements revealed that there was competitive adsorption between the depressant and collector and that the adsorption of the depressant CK102 prevented the collector modified sodium oleate from adsorbing onto the surface of minerals. The FT-IR and XPS results showed that the co-oxygen cross-linked component of the depressant CK102 chemisorbed on the surface of dolomite; the CaSiO3 precipitation was generated from the reaction of CK102 with Ca2+ groups on the surface of the dolomite; Al2MgO8Si2 precipitation was also generated from Mg2+ reacting with the sodium silicate and aluminum sulfate of CK102. The above adsorptions and reactions enhanced the hydrophilicity of the dolomite surface and the dolomite was effectively depressed.

The mechanism of CaCO3 in the gas-based direct reduction of a high-phosphorus oolitic iron ore

Wu Shichao, Li Zhengyao, Sun Tichang, Kou Jue, Xu Chengyan

Physicochemical Problems of Mineral Processing

2021

Vol. 57, iss. 4

117--124

Gas-based direct reduction and magnetic separation process was applied in treating a high-phosphorus oolitic iron ore, of which phosphorus mainly occured as Fe3PO7 and apatite. The mechanism of CaCO3 was investigated using XRD, SEM-EDS, and mineral phase analysis. Results showed that when no CaCO3 was added, most of the iron minerals were reduced to metallic iron, while Fe3PO7 was reduced to elemental phosphorus and mixed with the metallic iron particles. When a small amount of CaCO3 was added, CaCO3 preferentially reacted with SiO2, Al2O3 and other components, preventing them from reacting with FeO and resulting in the increase of iron recovery. When the amount of CaCO3 reached 25%, apatite was produced from the reaction of CaO and Fe3PO7, which could be later removed by grinding and magnetic separation.