Depends of several things: size of valve, pressure, orientation of valve, sand slurry composition: particle size, dry content, clean water or additions that may clog when dry, production cycle:continuous or batch wise, number of openings or closings, sealing and innards material, practical field experience of similar uses, price and availability of selected valve and spares, cost of shutdown, access to valve and change mode, temperature and orientation of valve.
Short answer: I would, all things above unknown, prefer a high quality knifegate valve, high-quality sealing with firmly held U-sealing and without 'pockets' where dry-stuff can assemble, easily changeable top sealing possible to change with valve in position, full opening, closing in both directions at zero pressure and up to necessary for your process (10 bar if possible at your size), mounted in a horizontal pipeline straight stretch, valve vertical with operator straight up.
A quench valve (elastic pipe with suitable layers, pinned down with outside yoke/devize) or a ceramic eccentric BFL-valve mounted horizontal might be alternatives at a (far) higher prices, not necessarily at a better cost/lifetime factor for a common use.