Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive ...Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage （the mass ratio of cement to fly ash to gypsum） is 1：1：6-1：1：8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan （RMB）, only 1/10 of that of traditional paste backfill system.展开更多
This study investigates the properties of cheeses made from camel milk, sheep milk and their mixtures. Cheeses were made using Camifloc enzyme as a coagulant after addition of calcium chloride. Camel＇s milk was mixed...This study investigates the properties of cheeses made from camel milk, sheep milk and their mixtures. Cheeses were made using Camifloc enzyme as a coagulant after addition of calcium chloride. Camel＇s milk was mixed with sheep＇s milk at the levels of 25%, 50% and 75%. Then, the cheeses were stored for 21 days in the whey at room temperature （37-40 ~C）. The study revealed that fortifying camel＇s milk with sheep＇s milk improved the processing properties of camel milk for cheese making. The addition of 50% sheep＇s milk to camel＇s milk reduced the coagulation time to about 46.15%. The addition of 25%, 50% and 75% sheep＇s milk to camel＇s milk revealed yield of 13.76%, 21.33% and 26.2%, respectively. However, the cheese made from pure camel＇s milk and sheep＇s milk revealed yield of 10.66% and 23.53%, respectively. There were significant （P 〈 0.001） differences in total solids, protein, fat, ash, acidity and overall acceptability among the cheeses made from different types of milk. The cheeses made from camel＇s milk after addition of 75% and 50% sheep＇s milk were the most acceptable compared to other cheeses. Hence sheep＇s milk could be added to camel＇s milk for improvement of cheese properties.展开更多
During the hydration process, the Ultra-fine Cements present specific physical and chemical characteristics; they are, very short setting time and high heat release. For special applications, such as rapid hardening a...During the hydration process, the Ultra-fine Cements present specific physical and chemical characteristics; they are, very short setting time and high heat release. For special applications, such as rapid hardening and early high strength mortars or concretes, these characteristics can be considered advantageous. Some commercial products used for concrete reinforcement and repairs are the Rapid Hardening Mortars, these mortars must develop a time of setting up to 3 h and an initial compressive strength of about 3.5 MPa once the hardening of the paste is reached. The objective of the present research work is to use Ultra-fine Cement for the preparation of a series of different Rapid Hardening Mortars （with different percentages of Ultra-fine Cement）, these mortars required the addition of a polycarboxylate-base specification F Superplasticizer. It was observed that the optimum water/cement （W/C） ratio for the hydration of the Ultra-fine Cements is W/C = 0.385. The Ultra-fine Cements were obtained by the High Energy Ball-milling technique at laboratory scale, 90% of the Particle Size Distribution is below 11 μm and the Blaine Specific Surface Area is over 9000 cm^2/g.展开更多
基金Project(2006BAB02A03)supported by the National Key Technology Research and Development ProgramProject(08MX16)supported by Mittal Scientific and Technological Innovation Projects of Central South University during 2008
文摘Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage （the mass ratio of cement to fly ash to gypsum） is 1：1：6-1：1：8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan （RMB）, only 1/10 of that of traditional paste backfill system.
文摘This study investigates the properties of cheeses made from camel milk, sheep milk and their mixtures. Cheeses were made using Camifloc enzyme as a coagulant after addition of calcium chloride. Camel＇s milk was mixed with sheep＇s milk at the levels of 25%, 50% and 75%. Then, the cheeses were stored for 21 days in the whey at room temperature （37-40 ~C）. The study revealed that fortifying camel＇s milk with sheep＇s milk improved the processing properties of camel milk for cheese making. The addition of 50% sheep＇s milk to camel＇s milk reduced the coagulation time to about 46.15%. The addition of 25%, 50% and 75% sheep＇s milk to camel＇s milk revealed yield of 13.76%, 21.33% and 26.2%, respectively. However, the cheese made from pure camel＇s milk and sheep＇s milk revealed yield of 10.66% and 23.53%, respectively. There were significant （P 〈 0.001） differences in total solids, protein, fat, ash, acidity and overall acceptability among the cheeses made from different types of milk. The cheeses made from camel＇s milk after addition of 75% and 50% sheep＇s milk were the most acceptable compared to other cheeses. Hence sheep＇s milk could be added to camel＇s milk for improvement of cheese properties.
文摘During the hydration process, the Ultra-fine Cements present specific physical and chemical characteristics; they are, very short setting time and high heat release. For special applications, such as rapid hardening and early high strength mortars or concretes, these characteristics can be considered advantageous. Some commercial products used for concrete reinforcement and repairs are the Rapid Hardening Mortars, these mortars must develop a time of setting up to 3 h and an initial compressive strength of about 3.5 MPa once the hardening of the paste is reached. The objective of the present research work is to use Ultra-fine Cement for the preparation of a series of different Rapid Hardening Mortars （with different percentages of Ultra-fine Cement）, these mortars required the addition of a polycarboxylate-base specification F Superplasticizer. It was observed that the optimum water/cement （W/C） ratio for the hydration of the Ultra-fine Cements is W/C = 0.385. The Ultra-fine Cements were obtained by the High Energy Ball-milling technique at laboratory scale, 90% of the Particle Size Distribution is below 11 μm and the Blaine Specific Surface Area is over 9000 cm^2/g.
