Hardening Accelerating Admixture Accelerators are used to increase the initial rate and speed of the chemical reaction between cement and the mixing water. Hardening accelerating admixture are used to reduce demoulding time or to speed access onto concrete floors and pavements and by this speed up the construction process. Hardening Accelerating Admixture,Hydrophilic Fibre Finishing Agent,Hydrophilic Polyester Copolymer,Hydrophilic Modifier For Amino Silicon Oil Liaoning Kelong Fine Chemical Co.Ltd. , https://www.kelongchemy.com
Accelerating admixtures can be used to increase either the rate of stiffening or setting of the concrete or the rate of hardening and early strength gain to allow earlier formwork striking and demoulding. Most accelerators achieve one rather than both of these functions.
Hardening accelerators are most effective at low temperature. Accelerators can be used with superplasticisers where early age strength is required, especially at lower temperatures.
Of chrome ore common chrome spinel iron ore minerals chromium [(Mg, Fe) Cr 2 O 4], aluminum chromite [(Mg, Fe) (Cr , Al) 2 O 4] and the chromium-rich tip spar [Fe (Cr, Al) 2 O 4] and the like; gangue minerals olivine, serpentine and pyroxene; sometimes associated small amounts of vanadium, nickel, cobalt and platinum group elements. In the identification of rock and minerals, the chemical composition of chrome spinel should be highlighted because it determines the concentrate grade and the ratio of ferrochrome.
The beneficiation of chromite ore is mainly by re-election method. Shakers and jigs are often used in production. Sometimes re-election concentrates are re-selected with weak magnetic or strong magnetic separation to further increase the grade and ferrochrome ratio of chromium concentrate.
The chrome spinel contains ore which is relatively high in iron or densely symbiotic with magnetite. In the concentrate obtained after ore dressing, the chrome grade and the ferrochrome ratio are both low, which can be considered as an ingredient for the production of ferrochrome by fire, or hydrometallurgical processing. For example, sodium dichromate method, chromium hydroxide method, reduction rust method, chlorination roasting acid leaching or electrolysis method. The production practice of low-grade ferrochrome concentrate by hydrometallurgy.
Chromite ore in associated form, such as PGE sulfide, arsenic compound or sulfur arsenide state, can be recovered by flotation. Olivine and serpentine ore, can be considered comprehensive recovery, for the production of refractory materials, calcium magnesium phosphate fertilizer diabase or the like.